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Filler Metal Product Approvals: From AWS to CWB, What Do They Mean?

By: Hobart Brothers

At one time or another you’ve probably browsed over the contents of a filler metal spec (or specification) sheet. Listed there, of course, is the standard data—available wire or electrode diameters, product characteristics, features and benefits, operating parameters and shielding gas requirements. In short, all the information you need to weld properly with that filler metal.

Also listed is a section with a rather enigmatic title:  Conformances and Approvals (sometimes called Specifications).

Understanding product approvals can be a first step
in learning to select the proper filler metal for your

Here, filler metal manufacturers list the product approvals that the wire or electrode bears according to agencies such as the American Welding Society (AWS), American Society of Mechanical Engineers (ASME), American Bureau of Shipping (ABS), Det Norske Veritas (DNV), Lloyd’s Register, or the Canadian Welding Bureau (CWB).

Gaining and listing a particular product approval from one of these regulatory agencies signifies the filler metal manufacturer’s commitment to quality and safety. It means their product is proven to yield specific mechanical and chemical properties as needed for critical applications like structural steel erection, shipbuilding, offshore platforms or petrochemical piping.Understanding the research, development and testing that filler metals undergo to meet the requirements of these agencies can be difficult, but knowing the basics of what the resulting product approvals signify doesn’t have to be.

Familiar Territory?  A Look at AWS and Similar Product Approvals
AWS or American Welding Society does not provide product approvals per se, but rather the agency sets forth standards to which filler metals need to conform.

To begin, AWS provides specifications for filler metals. A specification refers to a group of filler metals that has been formulated for welding on a particular base material, such as AWS 5.20 (fully, AWS 5.20/5.20M:2005), which is ‘Specifications for Carbon Steel Electrodes for Flux-Cored Arc Welding.’  For every type of material, electrode, wire and welding process, AWS sets forth similar specifications.

Within each AWS specification are multiple AWS classifications, standards to which filler metal manufacturers develop their products. Each classification bears an alphanumeric formula that represents specific mechanical and chemical properties. The classification also provides important information on how the filler metal should be used to ensure the stated weld properties are achieved.

For example, within the AWS A5.20 specification is a flux-cored wire with the AWS classification: E71T-1C H8.  Following is a breakdown of each component of that classification:

•    ‘E’ signifies electrode.

•    ‘7’ indicates the wire’s tensile strength measured in pounds per square inch (psi), or here, 70,000 psi.

•    The first ‘1’ refers to the wire’s all-position welding capabilities. Note: A ‘2’ would indicate flat/horizontal welding position capabilities.

•    ‘T’ denotes that this is a tubular wire, specifically here, a flux-cored one. AWS uses a ‘C’ to refer to                metal-cored wires.

•    The next ‘1’ indicates the wire’s usability, including that this wire has a rutile slag system and operates on the electrode positive (DCEP).

•    ‘C’ indicates the wire requires a CO2 shielding gas. An ‘M’ would be listed for a wire that requires an Argon/CO2 shielding gas mixture.

•    Finally, ‘H8’ specifies how much diffusible hydrogen is in the weld metal. Here, there is less than 8 ml. of hydrogen per 100 g. of deposited weld metal. (Note: the lower the number, the less hydrogen and the lower the chance for hydrogen-induced cracking in the final weldment).

Labeling a filler metal with a particular AWS classification is a promise of quality on the part of the filler metal manufacturer. It means that they have created a product that provides the weld properties its classification requires under standardized test conditions. AWS, however, does not inspect or witness testing. An AWS classification is also a guideline that dictates filler metal selection for critical welding applications.

For instance, the AWS fabricating code D1.1 dictates the design and welding requirements for structural steel. But it also determines acceptable filler metals for the job. By way of example, the AWS A.520 specified E71T-1C H8 classification discussed thus far would be suitable for certain applications under the AWS D1.1 code. An example would be the welding of Group II steel, such as A572 grade 50 steel, A36 steel, or A992 used on structural beam or column splices. It is generally the duty of an engineer of record or a certified welding engineer involved with fabrication to obtain a certificate of conformance (also called a ‘C of C’ or a typical cert) as evidence that a particular filler metal meets a certain specification and classification. AWS is not the only agency that requires filler metals to conform to certain such properties. In fact, the American Society of Mechanical Engineers (ASME) uses nearly the same nomenclature for its product approvals.

For example, the ‘Specifications for Carbon Steel Electrodes for Flux-Cored Arc Welding’ designated by AWS A.520 would be listed under ASME standards as: ASME SFA5.20.  ASME also prescribes a set of fabricating codes that dictate what filler metals are required for critical applications.  Like AWS codes, these are designed to ensure filler metal quality and the overall safety of the structure or components being welded.

ABS, Lloyd’s, DNV and CWB:  Keeping Filler Metals Safe for Land and Sea
The American Bureau of Shipping (ABS) is an organization whose primary function is to oversee the production of marine vessels and offshore platforms.  They do, however, also govern product approvals for filler metals that are acceptable to use on these applications. For a filler metal manufacturer to obtain ABS product approval, it must regularly have its products audited for quality, which includes an onsite visit to view production and to conduct weld testing. Upon successful completion of that testing, ABS then certifies the product to what is called a grade.

For the previous AWS E71T-1C H8 flux-cored wire example, ABS could provide a product approval of: ABS Grade 2SA or 2YSA. Like AWS classifications, these grades can again be broken down according to mechanical and chemical properties:

•    ‘2’ indicates the wire’s impact strength or toughness at a given temperature (also called Charpy V-notch). Here, that temperature is -20 C (-4 F). A ‘3’ would indicate -30 C (-22 F) and a ‘4’ equals -40 C (-40 F).

•    ‘SA’ signifies the wire can be used in a semi-automatic welding process.  Note, a semi-automatic approval also encompasses an automatic welding process approval.

•    When present, a ‘Y’ indicates the filler metal provides high yield strength (over 50,000 psi).

Similar to ABS are Lloyd’s Register and Det Norske Veritas (DNV).  Both agencies oversee shipbuilding, oil and gas pipelines, and energy structures worldwide, along with providing product approvals of filler metals for these applications. Lloyd’s especially tends to oversee product approvals for consumables used in structures around Europe. DNV commonly oversees the development of platforms intended for the North Sea, and with this construction, filler metals that are capable of producing welds to withstand the extreme cold of that water.

Lloyd’s Register lists its product approvals using a similar system as ABS.  As in the running example of the AWS E71T-C filler metal, this wire could have Lloyd’s approval of 3Y40S H10. Here:

•    ‘3’ again refers to impact strength at a given temperature, which here is -30 C (-22 F).

•    ‘Y40’ indicates tensile strength in megapascals (MPa), the metric version of pounds per square inch (psi). Here, it is 400 MPa.

•    ‘S’ signifies the wire is designed for semi-automatic welding.

•    ‘H10’ refers to the amount of diffusible hydrogen, here 10 ml per 100g of weldment.

A DNV product approval for this wire would look quite a bit different:  DVN II YMS. The formula’s breakdown is, however, similar to that of other agencies.

•    ‘II’ is used to indicate impact strength at a given temperature, which in this case is -20 C (-4 F).

•    ‘Y’ is again a reference to the wire’s high yield strength.

•    ‘M’ signifies the wire can be used for multi-run welding.

•    ‘S’ is a signifier of the wire’s use for semi-automatic applications.

Like its American counterpart, the Canadian Welding Bureau (CWB) has distinct requirements that must be met for a filler metal to bear its product approval. That approval, like one from AWS, comes in the form of a classification.  CWB also provides specifications for families of filler metals, along with codes for fabrication and filler metal selection.

A product approval or CWB classification for a carbon steel flux-cored wire similar to the previous example could be labeled: E491T-9 H8. The breakdown is as follows:

•    ‘E’ indicates electrode.

•    ‘49’signifies tensile strength in megapascals (here, 490 MPa or about 70,000 psi).

•    ‘1’ shows the wire offers all-position welding capabilities.

•    ‘T’ indicates it is a tubular wire.

•    ‘9’ signifies that the wire offers low temperature impact values (down to -30 C or -22 F).

•    ‘H8’ indicates the wire has 8 ml of diffusible hydrogen per 100 g of weldment.

Again, for a filler metal manufacturer to gain a product approval from CWB, its products must undergo testing on a regular basis.  CWB in particular requires testing every two years, while some of the other agencies require annual testing for a filler metal to continue bearing its product approval.Whichever the testing frequency, the goal is the same: to ensure quality and safety. When the filler metal you choose bears a specific product approval or states that it conforms to a particular standard, you can be assured that it does.

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