Welding Inspection / Welders Qualification Test (WQT) / Quality Assurance & Quality Control (QA/QC)

• Preparation of welding inspection procedure and testing based on clients compilation of necessary materials specification data based on standard codes.
• Witness qualification of welders and certify those who qualified the testing.
• Control quality of work in progress and check/witness every stage of work based on standards.

Read more:http://www.ndtphils.com/services/industrial-inspection/welding-inspection-welders-qualification-test-wqt-quality-assurance-q

Inspection and Testing for Welding Procedure Qualification

Welding Procedures are the guidelines used to perform a weld.  They are designed to provide a record of the welding variables used and the inspection results obtained during the procedure qualification test.  They can also provide the instructions for the welder to use in production in order to produce acceptable welds.  Usually welding procedures are developed in accordance with a welding code or standard, and with few exceptions*, require that physical weld samples be produced, inspected, and tested to establish qualification.  Welding procedures are usually divided into two categories, the Procedure Qualification Record (PQR) and the Welding Procedure Specification (WPS).

Procedure Qualification Records are the documented values used during the actual welding test and all the inspection and test results obtained from the actual test samples.

Welding Procedure Specifications are usually documented work instructions that can be used by the welder to conduct welding operations, and are based on, but not necessarily the same as, the parameters used for the Procedure Qualification Record.

We will consider the Procedure Qualification Record and the inspection and testing performed during its qualification.

Qualification testing of a welding procedure normally requires documentation to show all the variables used during the welding test and the documented inspection and test results.  The variables required to be documented are typically such items as:  welding process used, size, type and classification of filler alloy, type and thickness of base material welded, type and polarity of welding current, amps and volts recorded, travel speed during welding, welding position, type and dimensions of joint design, preheating temperature, interpass temperature, post weld heat treatment details, and others.  In addition to the recording of all the welding variables used during the test, in order to qualify a welding procedure, details of the inspection and test results must also be recorded.  These records must show that the inspection and testing has proven that the weld samples have met or exceeded the specified standard requirement.  The typical types of inspection and testing for each sample for Welding Procedure Qualification are: 

Inspection and Testing for Fillet Welds (Tee Joints) -  This involves visual inspection of the completed weld, followed by two macro etches, and one fillet weld break test.  The welded sample is first inspected for any visual discontinuities and then sectioned, and two small samples removed at predetermined locations.  These small samples are polished across their cross-section and then etched using some type of mild acid mixture, dependent on the base material used.   The remaining welded sample is used as the fillet weld break test and is broken against the weld to reveal the internal structure of the weld for inspection.

Inspection and Testing for Groove welds (Butt Joints) – This involves visual inspection, followed by two transverse tensile tests, two root bend test and two face bend tests. (These tests are typical but may differ dependent on material thickness, type and standard requirements.  Different and/or additional testing, such as side bends, all weld tensile tests, impact testing or other testing may be required.)  The completed weld coupon, after visual inspection, is divided into predetermined small sections. Each section is prepared, usually by machining, to specific dimensions as prescribed by the standard.  Each small sample is then tested mechanically to determine its characteristics.  These samples are then inspected to determine their acceptability, against specified acceptance criteria, as laid down by the applicable code or standard.  Typically the standard will provide the maximum size and location of various weld discontinuities and/or, as relevant, values such as minimum tensile strengths or minimum desired impact properties.

Samples that are found not to have discontinuities that exceed these specified limits, and that meet or exceed the minimum values as specified in the standard, will be acceptable, and the welding procedure will be qualified.

The welding procedure is an important part of the overall welding quality system, as it provides documented evidence that inspection and testing has been performed to ensure that welding can be conducted to meet a recognized standard.

* One exception to welding procedure qualification is the D1.1 Structural Welding Code for Steel, which will, under some circumstances, allow the use of pre-qualified welding procedures, however these procedures are still required to be documented and meet all of the relevant code requirements.

Read more: http://www.esabna.com/us/en/education/knowledge/weldinginspection/Inspection-and-Testing-for-Welding-Procedure-Qualification.cfm

How to Get Customers

First, find 5 to 10 machine shops that are pretty much 2 or 3 man operations.
Then, Along with a business card, drop off a small sample weld. (Be creative here) I knew a guy who would weld single edge razor blades together as his calling card. He pretty much sucked at welding other than that but the point is it impressed a lot of people... and it was memorable.
In marketing 101 they call this lumpy mail.

Another idea is welding some beer or coke cans together like in the pic above. How many other welding shops do you think left welded razor blades or welded aluminum cans with a business card? None!
I guarantee you none!
Leaving your business card does not work if it gets forgotten or tossed.

Anyway, these small machine shops usually have people who can weld but are not usually great welders.
They are machinists.
Their time is much better spent machining. When orders come in for intricate parts made from expensive materials and with thousands of dollars of machining required, They will gladly give you the welding work to keep their jack leg welder from screwing the parts up.
What machine shop owner wants to pay premium prices for materials and machining labor only to have an amateur welder cobble up the part by migging where he should tig and tigging where he should mig?
Now obviously, if you can’t weld razor blades or beer cans in the first place, you wouldn’t try that. (and you might even need to reconsider starting a welding business at all) But what about other objects?
What about two small pieces of diamond plate? Say 2 1-1 /2 inch squares so that it would be about the size of a business card?
You could even have your contact info etched on it. Don’t forget to run beads on the edges also. If this all seems too difficult then guess what? Don’t quit your day job.
You will need to be able to do this and more if you want your own welding business.
In fact, in my opinion you shouldnt  quit your day job until it starts costing you money by not being able to keep up with your own shops work.

Read more:  http://www.weldingtipsandtricks.com/starting-a-welding-business.html

Welder Business Cards

Welder

Ordering Welder Business Cards

With over 6 out every ten jobs being found in manufacturing industries, working as a welder, solderer or brazer can really pay off.

Welder Business

And according the U.S. government, job prospects for qualified people in these fields should be excellent as employers have been reporting difficulty finding qualified people. Help employers find you by creating high quality business cards that will make you get noticed and get hired.

Business Cards for Welders, Solderers, Brazers

Whether you're an independent worker trying to find jobs on new projects or a company man looking to make some extra cash after work, having your own business card gives you freedom. You'll hand out cards to friends, family members and coworkers, post them in neighborhood restaurants and shops and let them speak for themselves. Phone calls come with word of mouth, and your business card is your key to getting talked about.

Read more: http://www.printbusinesscards.com/ordering/Welder-Business-Cards.php

Welding Codes and Standards

Many aspects of the design and fabrication of welded components are governed by documents known as codes and standards.  Other names used for such documents include guides, recommended practices, regulations, rules, and specifications.  These documents are often specified by an end user/purchaser as a contractual agreement in order to control the characteristics of the welded fabrication that may affect its service requirements.  They are also used by the manufacturer to assist in the development and implementation of their welding quality system.  Many end users of welded components have developed and issued specifications that have been compiled by them to address their specific requirements.  Such specifications may be limited in application and related only to that customer’s situation and requirements.  National interest in areas such as public safety and reliability has promoted the development of welding codes and standards that command broader recognition both on a national and industry-specific basis.  Numerous committees have been developed over the years within national engineering and technical societies that continue to evaluate the needs of industry and develop new welding codes and standards.  Such committees are comprised of members who are technical experts and represent all interested parties such as manufacturers, end users, inspection authorities, and government agencies.  The membership of these committees is balanced in order to prevent any one interest group from controlling the committee. On completion of a new or revised document by the specific committee, it is usually then reviewed and approved by a review committee, and if accepted, then published in the name of the applicable engineering society.

Documents that have significant influence upon public health and safety are sometimes adopted by legislative bodies or by federal regulating agencies.  In those jurisdictions, such documents become law and are often referred to as Codes or Regulations. 

The welding inspector should be aware of what codes or standards are applicable within their jurisdiction, understand the requirements of the relevant documents and perform their inspection accordingly.

Read more: http://www.esabna.com/us/en/education/knowledge/weldinginspection/What-you-should-know-about-welding-codes-and-standards.cfm

ASME and AWS welding codes similarities and differences

Welding codes are designed to improve the quality and efficiency of welding and are used to qualify welders. Predominate among welding codes in the U.S. are those authored by ASME and AWS. This article provides a brief overview of the similarities and differences in these codes.

The most commonly used codes for qualifying welders are the American Society of Mechanical Engineers (ASME) Section IX and American Welding Society (AWS) D1.1. Committees and subcommittees comprising volunteer workers interested in furthering the quality and efficiency of the welding industry work together to develop these codes.

We all have heard that ASME codes are more stringent than AWS codes and vice versa. In some areas both are the same. In others they are very different.

The most obvious difference between ASME Section IX and AWS D1.1 is that D1.1 addresses fabrication, erection, inspection, and welder and welding procedure qualification. ASME is specifically for welder and welding procedure qualification. A "code of construction," such as ASME Section VIII, Division I, must be used in conjunction with Section IX for fabrication.

Some work contracts require that a specific code be used for qualifying the welders, but in many cases either code is sufficient. If the job consists totally of structural welding and the contract specifies the AWS Structural Code, then that is the code that must be used for all aspects of the job.

If the job entails pressure vessels or piping, the ASME Boiler and Pressure Vessel Code must be used.

If the job is related to ductwork associated with a boiler, the contract usually allows qualification with either code. Choosing a specific code when one is not specified in the contract often involves a fine line.

Qualification Basics

The basic contents of a procedure qualification are the same in both programs.

The welding procedure specification (WPS) is a document that is intended to provide direction for the welder. It also depicts the joint design and welding materials, parameters, and technique and code requirements.

The procedure qualification record (PQR) is a record of test results for the welds made in accordance with the WPS. Destructive testing (tensile pulls, bends, etc.) is required for PQRs in all codes. AWS D1.1 also requires nondestructive testing for procedure qualification. ASME Section IX does not.

The welder qualification test record (WQTR) comprises the results of a test to prove that a welder is qualified to weld to a certain WPS. It includes qualification of the range of base materials, weld materials, positions, and so forth. These tests consist of guided bends, breaking of fillet welds, and macroetching. In some cases, the test coupons may be radiographed in lieu of destructive testing.

AWS D1.1 Specifics

The AWS D1.1 code qualification is specifically for carbon and low-alloy metals. The minimum thickness addressed is 1/8 in. The maximum yield strength addressed is 100 KSI.

This code, generally used for buildings and support structures, is useful for fabricating and erecting any welded structure.

Materials for Prequalification by AWS D1.1

The prequalification Section 3 of AWS D1.1 lists materials for prequalifying the WPS. These materials are listed in groups that are assigned Roman numerals. Although the groups reflect a somewhat ascending alignment as to the yield strength, there are instances of overlapping within three of the four groups.

Group I lists the lowest-yield-strength materials from 30 KSI to 46 KSI. Group II lists materials at 36 KSI to 80 KSI. Group III, 46 KSI to 90 KSI. Group IV, 70 KSI materials only. Each material list shows matching electrode, and filler metal, to be used to establish prequalified procedures.

If a fabricator wants to use a material that is not listed in the table, a procedure must be qualified by testing and with a written PQR.

ASME materials are listed by "P" and "S" numbers. There are very few restrictions as to size and strength of material. This is a reason for qualifying welders and procedures to the ASME Section IX when possible.

Welding codes are intended to improve skills, processes, materials, and equipment. They are important in achieving maximum quality and efficiency.

Read more: http://www.thefabricator.com/article/shopmanagement/asme-and-aws-welding-codes-similarities-and-differences

How do I position my TIG torch for different types of joints?

	Butt welds
	When welding a butt joint, center the weld pool on the adjoining edges. When finishing, decrease the heat (amperage) to aid in filling the crater.
	Lap joint
	For a lap weld, form the weld pool so that the edge of the overlapping piece and the flat surface of the second piece flow together. Since the edge will melt faster, dip the filler rod next to the edge and make sure you are using enough filler metal to complete the joint.
	T-joint
	When welding a T-joint, the edge and the flat surface are to be joined together, and the edge will melt faster. Angle the torch to direct more heat to the flat surface and extend the electrode beyond the cup to hold a shorter arc. Deposit the filler rod where the edge is melting.
	Corner joint
	For a corner joint, both edges of the adjoining pieces should be melted and the weld pool should be kept on the joint centerline. A convex bead is necessary for this joint, so a sufficient amount of filler metal is needed.
	Read more : http://www.millerwelds.com/resources/tech_tips/TIG_tips/hints_tips.html

More jobs for Pinoy welders in Canada

VANCOUVER - Thousands of new jobs in the skilled trades were created in British Columbia when the federal government gave the Vancouver Shipyards the $3.3 billion contract to build 10 new non-combat ships for the Canadian Coast Guard last year.

This includes jobs in welding and pipe-fitting. Anticipating a possible shortage of qualified tradesmen, the Canadian Welding Bureau accredited test centers in the Philippines to screen well-trained welders.

"The welders that we are training in Canada right now are not sufficient to fill that vacuum that's why the Canadian government is looking of hiring temporary workers from outside, and right now, the Philippines is a very favorable place to hire the welders," said Bob Montes, certification services representative of the Canadian Welding Bureau.

Montes added that welders will also be in big demand when construction for the pipeline from Alberta to British Columbia begins.

He said Filipinos have a natural skill for welding and they have a huge plus over others.

"The advantage of the Filipinos is because they can understand and they can read and comprehend standards. When they come here, it's easy for Canadians to give them instructions. If they cannot follow instructions, it will become a safety issue here," Montes said.

He added a skilled welder can earn from 50 Canadian dollars (around P2,000) plus per hour.

Currently, there are only three centers that are accredited by the Canadian Welding Bureau: Brilliant Metal Works, Zoie Training Center and Primary Structures Educational Foundation, all based in Cebu.

Those who pass the test here will get a welding card that is valid anywhere in Canada.

With these developments, the Philippine Labor Office is confident that Canada will continue to hire more temporary foreign workers despite charges that the program is stealing jobs away from Canadians.

"There will always be a need for temporary foreign workers in Canada. If you judge it from yung the last five years, 2009, 10, 11, 12, until now, talagang pataas nang pataas yung numbers nila, Canada-wide and western Canada also especially Alberta, nandoon talaga yung boom," said Atty. Bernardino Julve.

Read more: http://www.abs-cbnnews.com/global-filipino/01/15/14/more-jobs-pinoy-welders-canada

Welding Different Types of Steel

Welding Mild Steel

These days mild steel is usually Carbon Manganese steel. Traditional mild steel used to contain less than 0.10% Carbon in Iron but it is rare these days. Now Carbon Manganese steels have taken over and are commonly called mild steel. They contain more Carbon and also Manganese which improves the strength whilst retaining the ductility / malleability.

Steel grades known as S235, S275 and S355 are Carbon Manganese steels, as well as the now obsolete grades such as BS4360 43A and 50D.
These steels are eminently weldable using 6013 electrodes or G3Si1 (SG2) MIG wire up to 18mm thick. Above that its probably wise to change to 7018 electrodes but the wire can remain as G3Si1 or SG2. This MIG wire is usually low hydrogen, often lower than low hydrogen electrodes, but beware of some of the lesser known brands.
Some of the higher grades of mild steel need low hydrogen rods to match the strength, and some need low alloy (such as 1% Nickel steel) for strength and low temperature toughness.

Mild steel structure during lifting load test

The thicker the steel the more stresses and strains are produced by the heat of welding. 7018s produce a cleaner, more ductile and stronger weld metal better equipped to withstand these higher stresses. Also the thicker the plate the greater the chance of hydrogen induced cracking. 7018s are low hydrogen and as such are less prone.

• Less than 18mm use 6013
• Greater than 18mm use 7018
• Increasing thickness use preheat

Dye penetrant test on mild steel lifting eye

Mild Steel MIG Wire SG2 or SG3

Just to confuse us the designations SG2 and SG3 are now obsolete, replaced by G3Si1 and G4Si1 respectively. That’s right SG2 is now G3Si1 and SG3 is now G4Si1.
The old A18 designation is really SG2. The American spec AWS ER70S-6 encompasses both the G3Si1 and the G4Si1, although for commercial/ production reasons it is more likely to be G3Si1.
What is the difference? Well G4Si1 has higher Silicon and Manganese making it both higher strength and better able to cope with rusty steel plate without producing porous welds.
Many believe SG3 or G4Si1 is higher grade, better quality. It isn’t its just different. Because of the higher Si it flows better and for this reason many welders prefer it to SG2. SG3 also carries current better and will produce welds of acceptable appearance on settings at least 100 amps higher than SG2, with advantageous affect on productivity. This grade also appears the best suited to some of the new electronic wave form control equipment such as Surface Tension Transfer (STT).

G3Si1 mild steel MIG welding wire 

 

Welding Engineering Steels

EN19 and EN24 / EN24T

EN19 and EN24 / EN24T are classed as Engineering Steels and are normally used because of their extremely high strength. They are used a lot in Fork Trucks (Tangs and Masts) and many other component parts.
In many cases the designer will specify their use without any thought for welding, and they are very difficult to weld.
It is possible to weld Engineering Steels successfully using mild steel fillers (7018s and SG2) but this method has a greater chance of hydrogen induced cracking and will also result in a weld much weaker than the parent.
The belt and braces approach is to preheat the parent to 250°C and weld 2 layers of E312 (electrode or wire) onto both of the surfaces to be welded. Allow to cool slowly, packed in sand or some other insulator. Once cool the surfaces can be welded together using the same 312 . If the joint is over 12mm thick it is important to stop welding after every layer and allow the weld to cool to room temperature. This is to prevent the weld becoming too hot and forming a very brittle microstructure known as Sigma.
The reason behind the use of E312 is that it is an austenitic / ferritic stainless steel with a tensile strength of over 800N/mm² which is close to the parent which could be over 1000N/mm². E312, being austenitic will absorb Hydrogen and therefore not allow it to pass into the Hydrogen crack susceptible structure of these steels.

• Preheat to 250°C
• Butter the faces with 2 layers of E312
• Allow to cool slowly
• Weld the buttered faces together using E312
• If over 12mm thick keep stopping and allow to cool

EN8

En8 is another engineering steel but not as problematic as En 24T etc. It used to be called 40 carbon steel meaning it had a high carbon content to impart high strength. These days it retains the strength levels (because of thermo mechanical rolling) yet it is much lower carbon so much easier to weld.
In fact if you use standard MIG wire (SG2) or a 7018 electrode you can weld it without preheat upto 18mm thick, over that a preheat of 100°C should prevent cracking.
All this assumes it is of western European origin. Some of the steel coming in from eastern Europe and the far east is loaded with carbon and may need up to 250°C preheat to prevent cracking.

Clevice fabricated from 18mm EN8 Steel. (E.T Brown and Son)

Welding Corten Steel

Corten is a trade name for Weathering Steel. In other words its steel that still goes rusty but it rusts a nice colour and it resists the spalling black lumps that fall off ordinary mild steel.
Corten contains small amounts of Chromium, Nickel and Copper which impart the weather resistance. It is used mostly in structural applications.
Many buildings appear to have been painted orange but in reality are untreated corten steel.

Corten is often used in outdoor sculpture. Stickleback by artist Alan Ross

When welding Corten the precautions are similar to mild steel except that you may need a special filler material to produce the weathering steel weld. (6013s are not acceptable.)

• If the plate is 10mm thick or less, and the weld is a single pass (eg a fillet weld), you can use an E7018 or SG2 MIG wire. This is because you will get enough dilution from the plate to render the weld weathering.
• If it's greater than 10mm thick or a multi-pass weld you need to use a filler containing approximately 1% Nickel and 0.5% Copper (otherwise mild steel), or one containing 2.5% Nickel (otherwise mild steel).

This will result in a weld which will “weather” like the plate.

Welding Cast Iron

There are many different cast irons, many of which are totally unweldable as they will crack when you heat them. Fortunately by far the most common and the most frequently used for car components (bell housings etc) is called Nodular or SG Iron.

Nodular Cast Iron is modified by adding an innoculant just before casting (Magnesium or Cerium) which changes the shape of the graphite flakes from pointed (stress raiser) to spheroidal (hence SG or Spheroidal Graphite). This grade welds relatively easily but there is a knack to it:

• Keep it cool not cold (around 50°C is a good indicator).
• Avoid long runs, 25mm max.
• Balance the welds across the joint - start at one end and then weld a bit at the opposite end.
• Use specialist Nickel Iron electrodes that run on low current. (MIG has no speed advantage and a coil of wire will be upwards of £1000.)
• After every weld peen the bead (tap it lightly with the round part of a ball pein hammer). When preparing the joint grind out the surface to be welded so you get a full penetration weld.
• If it’s a crack repair, grind out the crack, drill the ends to stop it propagating, and allow to cool to room temperature after every weld.

Casting repair using Lincoln Cast (Nickel Iron) Rods. (W.H.Hannaford)

Preheat or Not?

To preheat effectively you need to heat the casting to 500°C (I wouldn’t fancy trying to weld it when its that hot). Also the preheat has to be applied consistently, no hot spots or cold spots. Castings are usually variable section thickness so the thick bits need to be the same temperature as the thin bits. Really the only way to effectively preheat is to use an oven / furnace which makes it very difficult. Therefore the cool method is the most widely used.
The weld metal filler specifically designed for cast iron is either pure nickel or nickel-iron. It is possible to use mild steel but it will pick up carbon from the cast iron and become very hard and brittle which makes it crack sensitive and very difficult to grind back to shape. Nickel blocks the migration of carbon therefore it doesn’t become brittle, even the nickel-iron alloy, so it can be machined and it retains its elasticity.
The electode coatings used are designed to promote operation at low currents and consist mainly of graphite which is an excellent electrical conductor. Why is this type of coating only used on cast iron rods? For exactly the same reason as mentioned in the earlier paragraph. Graphite would add carbon to, and embrittle, virtually any steel but not nickel rich alloys.

The completed repair. (W.H.Hannaford)

Welding Weldox or RQT or (generic) S690 Steels

Weldox, RQT and S690 are the same steels and are usually known by the trade name Weldox. They are very high strength steels but have lean compositions (low alloy). Their strength is achieved by thermo-mechanical means: rolling and quenching and tempering (RQT).
These days they find use in all sorts of fabrications from battery powered vehicles to skips, in fact anywhere where their increased strength can be used to lighten the fabrication. If the strength is higher you need less thickness to provide the same overall strength. Thinner equals lighter and alighter skip can hold more rubbish but maintain the same overall weight.

Weldox 700 ready to fabricate digger bucket (Flynns Buckets)

These steels provide little problems in welding providing the correct consumables are used in the correct procedure.
As far as consumables are concerned you need an E10018-G or a 11018-G electrode or an ER100S-G or ER110S-G wire.
The procedure is reliant on the correct preheat for the thickness of plate involved. Preheats increase with thickness. Over 30mm you need 75°C and over 70mm thick its 100°C. These thicknesses are combined so if its 20mm to 20mm its 40mm combined. These preheats assume a heat input of 1.7kJ/mm which is common with electrodes but more difficult with MIG (the tendency in MIG is for lower heat input so higher preheats are required).

Weldox welded using MIG process (Flynns Buckets)

Heat Input is a number that relates to the energy applied to the weld. It is Volts x Amps x Time / Length.
Given that a process such as MIG will weld faster than MMA, the time taken for a unit length will be shorter so the divider will be greater and thus the heat input will be lower (even though the amps might be higher). Think of it like waving a gas flame across the weld. Do it slowly and it will get the plate hotter than wafting it across very quickly.
The greater the Heat Input the more heat in the weld.

The completed digger bucket (Flynns Buckets)

 

Welding Hardox Steels

Hardox is a trade name of SSAB (equivalents are available from other manufacturers).
It is wear plate, designed to last longer than standard mild steel. There are various hardness levels with 400 and 500 being the most common.
It is relatively lean in alloy content and as such is not that prone to cracking especially if a few rules are followed.
Hardox is weldable using 7018 electrodes or standard mild steel MIG wire (SG2) but will need preheat for thick sections.

Hardox blade and teeth on digger bucket (Flynns Buckets)

Hardox 400 40mm combined thickness will need 75°C preheat whilst Hardox 500 20mm combined thickness will need 100°C. Thicker sections will need higher preheat, and in both grades the interpass temp should be kept to 150 - 175°C.
If preheating is a problem it is possible to weld without preheat using a 309L type electrode or wire, but remember stainless cannot be burned with standard oxy-acetylene. Some of the digger bucket repairers once warned me of this problem which gives them headaches on subsequent repairs.

Torch used to preheat hardox (Flynns Buckets)

Another consideration is that the weld will be softer than the plate. If this is a potential problem the weld can be capped using a hard facing electrode or wire. A single pass with a 600 hardness consumable should match or exceed the hardness of the plate. 2 passes will exceed.
These hardness numbers are Vickers, there is also Brinell and Rockwell hardness scales. Basically all are tests that measure the indentation made by a standard shaped object (either a pyramid or a ball) under a standard load.

A multiple pass weld (Flynns Buckets)

Welding Wrought Iron

Most Wrought Iron isn't real wrought iron - gates and railings are normally shaped mild steel. Wrought means the production method not the shape.
There is very little new real wrought iron. The only place in the world that still makes proper wrought iron is The Real Wrought Iron Company in Thirsk, Yorkshire.
Wrought Iron bends better than mild steel and is very corrosion resistant - it hardly rusts. 100 year old bridges and old railway stations are still standing because they are made from proper wrought iron.

Eiffel Tower photo by Brian Tibbets

Wrought Iron consists of layers of slag interlaced with almost pure Iron.
Therefore if you are welding the surface you will be welding pure iron which is easily done. There is strong possibility that you will get lamellar tearing (pulling the layers apart) but its difficult to avoid so it has to be accepted.
If you are welding “through the thickness” you are trying to weld slag which is virtually impossible without getting porosity or cracks.
If the weld doesn't need to be “perfect” a 6013 will do an acceptable job.
If you need a porosity free weld you must use a 7016 type rod and weld, grind back to clean metal, weld again, grind again. Eventually you will get a weld of acceptable appearance, metallurgically it wont be sound but it will probably be stronger than the wrought iron.

Failure in an old beam showing laminar tearing

Welding Stainless Steels

Grades of Stainless Steel

To make a steel "stainless" it needs to contain a minimum of 12% Chromium (Cr). The Cr oxidises in the atmosphere forming a passive layer on the surface. This layer, unlike coated steels, is self repairing should it be scratched.
The problem with 12% Cr is that it is fairly brittle and only provides the minimum corrosion resistance. Increasing the Chromium content to 17% improves corrosion resistance but increases brittleness. Adding 8% Nickel makes the steel ductile again. Thus 18/8 stainless was born (304). 316 / 316L has additional Molybdenum and higher Nickel which provides greater corrosion resistance.
With stainless when you see two numbers they always refer to the Chromium and Nickel content - 18/8 is 18%Cr and 8%Ni. If you see 3 numbers like 19/12/3 they refer to the Chromium, Nickel and Molybdenum content. 316L is 19%Cr, 12%Ni and 3%Mo.

Stainless seat used in a changing room. (Paul Holland Fabrications)

Welding Stainless

There are 2 common grades of stainless: 304L (welded using 308L filler), and 316L which is welded using 316L filler.
Why is 308L filler used for 304L? Basically there are a number of grades that do similar jobs, 302L, 303L and 304L (they are 17/7, 18/8 and 19/9 respectively). 308L is 20/10 so can be used to weld all 3 grades.
Stainless is easy to weld but very difficult to keep flat, the coefficient of linear expansion is 1.7 times that of mild steel. There isn’t much you can do about that except to weld it quickly and by doing so minimise the heat input.
304 and 316 (as opposed to the L low carbon versions) suffer from weld decay. When heated to welding temperatures the Chromium combines with the Carbon leaving the steel short of Chromium and therefore unable to self repair itself.
This was virtually eliminated by introducing stabilised stainless steels 347 and 321 which contain Niobium or Titanium which sacrifices itself to save the Chromium, however, when lower carbon versions 304L and 316L were introduced the problem of weld decay was eliminated. These days the higher (in fact, normal) carbon versions are only used for applications where heat resistance is needed.

Mashed potato extruder nozzle. 316 stainless with welds polished for hygene. (Paul Holland Fabrications)

Stainless Steel Filler Metal Choice

Select the metals to be welded from the purple bars to the top and right. The filler metal is in yellow where the two intersect.

304L	316L	310	347	321	410	430	Mild Steel
308L	308L	310	308L	308L	309L	309L	309L	304L
308L	316L	310	316L	316L	309L	309L	309L	316L
310	310	310	310	310	309L	310	310	310
308L	316L	310	347	347	309L	309L	309L	347
308L	326L	310	347	318	309L	309L	309L	321
309L	309L	309L	309L	309L	410/309L*	309L	309L	410
309L	309L	310	309L	309L	309L	309L**	309L	430
309L	309L	310	309L	309L	309L	309L	Mild Steel	Mild Steel

* depends on environment - if Sulphurous it must be 410
** preheat of 150°C required

Welding Stainless Steel to Mild Steel

The usual choice for the filler when welding stainless to mild is 309L. 309 is over alloyed stainless steel (19/10) so when diluted by the mild steel gives a deposit approximately like 308L / 304L.
There are other fillers that give a crack free weld, 312, 308MoL, 307 and 310 will all work but these are less widely available than 309L.

Dragonfly sculpture in stainless and mild steel. (Alan Ross)

Shielding gasses for MIG

The best gas for MIG welding stainless is 97.5% Argon +2.5% CO2. Previously an Argon/Oxygen mix was widely used, but this doesn't give as smooth a finish as the Argon/CO2 mix.
For mild steel welding 80% Argon plus 20% CO2 is common, with 95% Argon plus 5% CO2 often used for thin sections, but even 5% CO2 is too oxidising for stainless and will leave the weld looking black.

304 ductwork for an incinerator

The (Unofficial) History of Stainless Steel

Harry Brearley of Brown-Bayley Steels, Sheffield is often recognised as the inventor of stainless steel. My father worked for him and told me this story.
They were making a cast of 14% Manganese Steel and someone added the wrong alloy FeCr instead of FeMn. When they realised their mistake they scrapped the melt. It was stored outside awaiting use but no-one could decide what they could do with it. It stood there for months. One day Brearley noticed it hadn’t rusted and the rest is history. If you read the official version it is very different, more scientific.

Detail of stainless steel flange weld. (Race-Tech)

Hardfacing

Hardfacing is a way of modifying the surface of a component to withstand abrasion.
The most common grades of weld metal for hard facing are the Martensitic 300 and 600 Hv steels. The 300 is used when the component is to be machined or as an intermediate layer before the 600 hardness. The 600 is basically as hard as it gets but you will see weld metals claiming 1000Hv. These are hard particles in a softer matrix.
One of the best hard facing alloys contains 25 -30 %Cr with 4 - 5% Carbon which gives a very abrasion resistant overlay which is also quite ductile. Its probably worth paying that bit more as it will last a lot longer than the 600Hv alloy. It is especially good for ploughs and digger buckets. This grade is often called Chromium Carbide grade and is typically shown as having a hardness of 60 Rockwell C (Rc).

Hardfacing in cross patterns on the jaws of a crusher (Flynns Buckets)

Welding Chrome Moly (CrMo) Steel

This steel is mostly used in power stations. It is also called creep resistant steel which means that it doesn’t sag even at high temperatures.
It should be welded with similar consumables and you should follow a very precise method. Preheat and post weld heat treatment are almost always involved. The most common consumables according to AWS have a suffix of B2, B3 (something like E8018-B2) and are designed only for welding CrMo steels. Dont use these consumables for any other steels. They are highly crack sensitive.
The photo shows a power station steam pipe. Insulation covers heating coils were used to pre-heat the pipe to 250°C followed by PWHT of around 700-730°C.The welding consumables were TIG for the root deposit (AWS ER90S-B3, 2.4mm wire),then MMA 3.2 and 4.00mm electrodes for the fill and cap (AWS E9018-B3). Often FCAW is used for filling and capping these large bore pipes (AWS E91T1-B3), using 1.2mm wire and Ar/CO2 gas mix.

Welding a Chrome Moly steam pipe in a power station

Thin Walled Tube T45 or 4130 grade

A common question is what to use to weld thin walled tube T45 and 4130 used on roll cages and automotive parts. These are also CrMo steels.
If you read the books it will tell you that you need to preheat, slow cool and post weld heat treat. However, because they are thin walled tube you don’t need the preheat especially when you TIG weld. The heat of welding is enough. Use A15 or A18 wire, the strength levels don't match but the weld will be thicker than the tube to make up for it.

 

Read more: http://www.mig-welding.co.uk/steels.htm

 

Salary about a Journey Man Welder

Welders join metals in factories, repair shops and construction sites using more than 100 methods, including electrical current or arc welding. These days, many welders learn the trade in classes in high schools, technical schools and two-year colleges, although some employers hire inexperienced workers and train them through apprenticeships. After completing training classes or an apprenticeship, you qualify to work as a journeyman welder for a welder's salary.

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National Averages

The U.S. Bureau of Labor Statistics groups welders in its "Welders, Cutters, Solderers and Brazers" job category. The average pay for these workers was $18.46 an hour or $38,410 a year as of 2012. The lowest-earning 10 percent received annual salaries of $24,720 or less, while the highest-paid 10 percent earned $56,130 or more. Half of welders surveyed earned yearly incomes of $29,730 to $44,970.

Industry Pay

A welder's pay depends in part on the type of employer. Architectural and structural metals manufacturing firms were the biggest employer of welders in 2012, paying an average annual income of $35,310, according to the BLS. Welders in agriculture, construction, and mining machinery manufacturing averaged $36,290 per year, while those in motor vehicle manufacturing averaged $33,420. Welders averaged $38,040 working for companies in the commercial and industrial equipment field. The top-paying industry for welders in 2012 was electric power, at an average of $62,850 per year.

Pay by Location

As with most jobs, a journeyman welder's pay also depends on the location. The BLS reports that welders in Alaska had the highest average salaries in 2012, at $69,390 a year. Hawaii ranked second at $58,430 a year, followed by the District of Columbia at an average of $56,580. Among metro areas, Anchorage, Alaska and Peabody, Mass. had the highest average pay for welders. In both places, average annual salaries exceeded $65,000 per year.

Job Outlook

The Bureau of Labor Statistics predicts 15 percent job growth for welders between 2010 and 2020, compared to 14 percent for all jobs. Manufacturing, defense and infrastructure repair will all produce more positions for welders. New welding school graduates and welders who are up-to-date on the latest technology will have the best job prospects. Those unfamiliar with the latest techniques will find the job hunt more competitive. However, welders able to relocate will have an easier time finding work.

Read more: http://everydaylife.globalpost.com/salary-journeyman-welder-11236.html

Whole Sale Welding Supplies

When it comes to Welding & Engineering Supplies in Ireland we will not be beaten on price or quality. We sell everything from MIG Welders, TIG Welders, ARC Welders, Abrasives, Plasma Cutters, Welding Consumables, Safety Gear, Welding Helmets & Spares, Gas Equipment, Power Tools, Hand Tools, Cleaning and Janitorial Equipment, Power Washers, Metalworking Machinery, Electrical, Generators and much more. We have over 3000 products online to choose from.

Our goal is to bring you the highest quality brand name products at the lowest prices anywhere in Ireland. We source 100% of our products from trusted manufacturers within Europe. Brands such as Parweld, SWP, R-tech Welding, Klingspor, Clarke, Silverline, Starrett, Hitachi, Honda. Names that people trust.

We supply to everyone: from the household customer and DIY Enthusiasts right through to the more larger companies throughout Ireland.

We currently stock all our items in our impressive warehouse in Rathcoole in Dublin. Orders can be placed on this easy to use, 100% Secure Website or over the phone by calling us. We hope you enjoy your shopping experience with us and if you have any questions, issues, or just want to chat please call us on 01 6040808.

NOTE: We do not have a trade counter. We only operate as an online retailer. 

Read more :http://www.wholesaleweldingsupplies.ie/

Good and Bad Stick Welds

Image Source: http://www.hobartwelders.com/elearning/

How Does a MIG Welder Work?

If you're thinking about getting into welding, you have to ask yourself what type of welding you are interested in doing before you buy any equipment. Most welding machines are capable of making most joints in metal, but they are all better at some jobs than others. By far the most universal welder is a MIG. You can use a MIG welder to weld thin gauge sheet metal or heavy steel pipe. A pro can make beautiful, smooth, deep welds with a MIG welder, but an amateur can get an adequate weld out of the machine, too. They are simple enough to use that you can plug the thing in, crank up the gas shield and start doing some welding -- ok, that's simplifying things more than a little bit, but the fact is MIG welders these days aren't tough to jump into at all.

So, what does MIG mean anyway? Before we get there, let's talk about arc welders. Arc welders use high voltage electricity to generate enough heat to make a weld. There are different types of arc welders -- stick, TIG, MIG -- but the difference between them is not in the electricity they use or how they use it, but in the other element common to arc welders, a gas shield. The gas shield can be created by a flux that releases gas due to a chemical reaction, or by a cloud of gas released from a tank connected to the welder. In the case of a MIG welder, the tank is filled with a mixture named Metal Inert Gas by the industry. The gas recipe varies, but the name indicates that none of them will react with metal and add any contaminants to your weld. This gas is pumped through your welding cable from that metal tank you had to lease or buy. It comes out of the same nozzle your welding wire is fed through so it literally creates a protective cloud around the arc as you're welding.

A MIG welder is also a wire-feed type welder. The metal that it uses to create the weld material is held on a spool inside the welder. The type of material it uses depends on what type of metals you're joining, but it's always a metallic wire. For beginners, or for welders who need ultimate portability, some welding wire contains flux inside it, eliminating the need for a separate tank of welding gas. This works, but is inferior to a proper gas setup. The wire is fed through the nozzle coming out as you pull the trigger. The welding wire itself completes the arc that was started when you clamped the other electrode to your welding project.
A MIG welder has a number of different heat settings which allow you to set the machine to just the right power to get a deep weld with good penetration, but not so much power that you burn a whole in your project. Don't worry if you do this a few times before you get things right. Even seasoned welders are suprised from time to time and end up having to make last minute adjustments to their heat settings. There is also an adjustment to the feed rate of your wire. This will vary by project and equipment, but as you get to know your usual jobs and your welding machine, you'll fine tune your feed rate. It's always a good idea to do a test bead on some scrap metal before you start working on your valuable project. A properly set up machine that is welding clean metal will sound like bacon sizzling in a pan. Getting the heat and feed settings right before the real job is in front of you can save lots of time and money.

Read more: http://autorepair.about.com/od/glossary/a/How-Does-A-Mig-Welder-Work.htm

Welders in National and Regional Data

East Midlands – There are an estimated 37,700 employees in the regional workforce, in over 2,900 companies. There is a total requirement of 8,530 employees needed in the region between 2007 and 2014. Skills gaps in the region include: metal workers; Computer Aided Design (CAD); assembly line/production robotics; tool setting; tool makers; pattern making; and foundry skills. 48% of the workforce is employed as sheet metal workers. The largest industries in terms of employment are metal products, mechanical equipment, aerospace and automotive. Engineering employment is geographically concentrated around Derby City, Leicester City, South Derbyshire, Charnwood, Hinckley and Bosworth and Ashfield.

East of England – There are an estimated 28,100 employees in the regional workforce, in just over 3,340 companies. There is a total requirement of 9,960 employees needed in the region between 2007 and 2014. Skills gaps in the region include: welding skills; Computer Aided Design (CAD); tool setting; fabrication; Computer Aided Manufacture (CAM); Material Requirement Planning (MRP11); assembly line/production robotics; manufacturing; and toolmakers. 51% of the workforce is employed as sheet metal workers. The largest industries in terms of employment are mechanical equipment, electronics and metal products. Engineering employment is geographically concentrated around Peterborough, Huntingdonshire, South Cambridgeshire, Luton and Basildon.

London – There are an estimated 12,700 employees in the regional workforce, in just over 2,030 companies. There is a total requirement of 8,700 employees needed in the region between 2007 and 2014. Skills gaps in the region include: Computer Aided Design (CAD); Material Requirement Planning (MRP11); CNC machine operation; tool setting; fabrication; metal workers; toolmakers; carpentry/woodwork; and machine operator (unspecified). 47% of the workforce is employed as sheet metal workers. The largest industries in terms of employment are mechanical equipment, electronics and metal products. Engineering employment is geographically concentrated around Barking and Dagenham, Hillingdon, Ealing and Hounslow.

North East – There are an estimated 22,700 employees in the regional workforce, in 1,180 companies. There is a total requirement of 4,875 employees needed in the region between 2007 and 2014. Skills gaps in the region include: metal workers; Computer Aided Design (CAD); Materials requirement Planning (MRP11); welding skills; and craft skills. 56% of the workforce is employed as sheet metal workers. The largest industries in terms of employment are mechanical equipment, metal products and automotive. Engineering employment is geographically concentrated around Newcastle upon Tyne, Gateshead, Sunderland and Sedgefield.

North West – There are an estimated 44,300 employees in the regional workforce, in 3,700 companies. There is a total requirement of 13,595 employees needed in the region between 2007 and 2014. Skills gaps in the region include: CNC machine operation; technical drawing; welding skills; general engineering skills; moulding skills; fabrication; metal workers; and grinding. 49% of the workforce is employed as sheet metal workers. The largest industries in terms of employment are metal products, mechanical equipment and aerospace. Engineering employment is geographically concentrated around Fylde, Knowsley, Crewe and Nantwich, Stockport, Oldham and Preston.

South East – There are an estimated 33,000 employees in the regional workforce, in just over 4,300 companies. There is a total requirement of 10,120 employees needed in the region between 2007 and 2014. Skills gaps in the region include: Computer Aided Design (CAD); welding skills; assembly line/production robotics; fabrication; Computer Aided Manufacture (CAM); Computer Aided Engineering (CAE); Materials Requirement Planning (MRP); Materials Requirement Planning (MRP11); Statistical Process Control (SPC); tool setting; craft skills; general machining; metal workers; precision engineering; and foundry skills. 46% of the workforce is employed as sheet metal workers. Engineering employment is geographically concentrated around West Berkshire, Basingstoke and Deane, Milton Keynes, Eastleigh, Portsmouth, Crawley and Medway.

South West – There are an estimated 31,400 employees in the regional workforce, in just under 2,870 companies. There is a total requirement of 7,460 employees needed in the region between 2007 and 2014. Skills gaps in the region include: CNC machine operation; Computer Aided Design (CAD); Computer Aided Engineering (CAE); Computer Aided Manufacture (CAM); Materials Requirement Planning (MRP11); tool setting; welding skills; general engineering skills; fabrication; and precision engineering. 47% of the workforce is employed as sheet metal workers. The largest industries in terms of employment are mechanical equipment, electronics and metal products. Engineering employment is geographically concentrated around Tewkesbury, Cheltenham, Stroud, South Gloucestershire, Bristol, Swindon, South Somerset, Poole and Plymouth.

West Midlands – There are an estimated 86,300 employees in the regional workforce, in 5,850 companies. There is a total requirement of 15,730 employees needed in the region between 2007 and 2014. Skills gaps in the region include: CNC machine operation; fabrication; Computer Aided Design (CAD); assembly line/production robotics; welding skills; general engineering skills; general machining; Materials Requirement Planning (MRP11); Statistical Process Control (SPC); tool setting; moulding skills; metal workers; grinding; plating; and pattern making. 67% of the workforce is employed as metal making and treating process operatives. The largest industries in terms of employment are metal products, mechanical equipment and automotive. Engineering employment is geographically concentrated around Birmingham, Sandwell, Walsall, Coventry, Dudley and Telford and Wrekin.

Yorkshire and the Humber – There are an estimated 57,900 employees in the regional workforce, in 3,580 companies. There is a total requirement of 13,595 employees needed in the region between 2007 and 2014. Skills gaps in the region include: CNC machine operation; Materials Requirement Planning (MRP11); general engineering skills; metal workers; Computer Aided Manufacture (CAM); assembly line/production robotics; tool setting; moulding skills; and manufacturing. 72% of the workforce is employed as metal making and treating process operatives. The largest industries in terms of employment are metal products, mechanical equipment and automotive. Engineering employment is geographically concentrated around Sheffield, Leeds, Bradford, Kirklees, Rotherham and Kingston upon Hull.

Northern Ireland – There are an estimated 8,800 employees in the metals workforce. There is a total requirement of 500 employees needed per year between 2005 and 2014. 39% of the workforce is employed in the welding trades. Skills gaps include: welding; CNC machine operations; mechanical engineering skills; metalworking; and electrical engineering skills. The largest industries in terms of employment are electrical and electronics industry and the metals industry.

Scotland – There are an estimated 28,500 employees in the workforce, in just over 2,000 companies. There is a total requirement of 7,140 employees needed between 2007 and 2014. Skills gaps in the region include: CNC machine operation; Materials Requirement Planning (MRP11); metal workers; Computer Aided design (CAD); Computer Aided Manufacture (CAM); Computer Aided Engineering (CAE); Statistical Process Control (SPC); assembly line/production robotics; tool setting; general engineering skills; craft skills; fabrication; mechanical engineering; and turners. 62% of the workforce is employed as smiths and forge workers. The largest industries in terms of employment are electronics, metal products and mechanical equipment. Engineering employment is geographically concentrated around the City of Glasgow, Fife, South Lanarkshire, the City of Aberdeen, North Lanarkshire and West Lothian.

Wales – There are an estimated 30,000 employees in the workforce, in just under 1,450 companies. There is a total requirement of 4,350 employees needed between 2007 and 2014. Skills gaps in the region include: Computer Aided design (CAD); fabrication; CNC machine operation; welding skills; general engineering skills; general machining; precision engineering; and machine operator (unspecified). 75% of the workforce is employed as metal making and treating process operatives. The largest industries in terms of employment are automotive, basic metals, mechanical equipment and aerospace. Engineering employment is geographically concentrated around Flintshire, Neath Port Talbot, Newport, Rhondda, Cynon and Taff, Bridgend and Wrexham.

[N.B. Data derived from Annual Business Inquiry, 2007, Census, 2001, and Northern Ireland Census of Employment, 2007.]

Read more: https://nationalcareersservice.direct.gov.uk/advice/planning/jobprofiles/Pages/welder.aspx