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Nov 13, 2018

Understanding A5.36 Specification for Carbon and Low Alloy Steel Welding Wire


While not always easy to interpret, American Welding Society (AWS) specifications provide filler metal manufacturers with valuable information to guide the production of their welding wires and electrodes. 

They set forth requirements for the mechanical and chemical properties a filler metal must meet to bear a given classification. The welding professionals on AWS committees who oversee the development of these specifications take great care to set standards that offer exacting quality for welding most base metals. This in turn gives you confidence in using the product for your welding procedures.   

Welder standing next to large heavy equipment part welding

The A5.36 specification is an open classification for carbon and low-alloy
flux-cored and metal-cored welding wires that allows the products to bear
additional classifications to indicate mechanical properties and usability,
based on testing.

A newer specification, A5.36/A5.36M:2016 Specification for Carbon and Low Alloy Steel Flux Cored Electrodes for Flux Cored Arc Welding and Metal Cored Electrodes for Gas Metal Arc Welding, combines four other AWS specifications and is one that is garnering some questions. It combines:

A5.20/A5.20M:2005 Carbon Steel Electrodes for Flux Cored Arc Welding

A5.29/A5.29M:2010 Specification for Low-Alloy Steel Electrodes for Flux Cored Arc Welding

A5.18/A5.18M:2017 Specification for Carbon Steel Electrodes and Rods for Gas Shielded Arc Welding 

A5.28/A5.28M:2005 Specification for Low-Alloy Steel Electrodes for Low-Alloy Steel Electrodes and Rods for Gas Shielded Arc Welding 

So why has the A5.36 specification been developed? And what does it mean to you?

A5.36 open classification versus fixed classification
Traditionally, AWS prescribes fixed classifications for filler metals. This means a welding wire or electrode cannot be classified as offering any other mechanical properties than what have been determined within that classification. The only other options are designators that allow filler metal manufacturers to classify products with additional mechanical properties; however, these options are limited.  

For example, if a wire must meet a Charpy V-notch (CVN) impact toughness of 20 ft-lb. at -20 degrees Fahrenheit (or 20 ft-lb. at -40 degrees Fahrenheit with the addition of a J designator), then filler metal manufacturers can only classify it as that — even if changing shielding gas will improve its impact properties or the product is simply capable of achieving better properties. 

Conversely, the A5.36 is an open classification for carbon and low-alloy flux-cored and metal-cored welding wires that allows the products to bear additional classifications to indicate mechanical properties and usability, based on testing. It was designed with two key benefits in mind:

1) To create flexibility in classifying filler metals to meet a wider range of application and marketplace requirements. The emergence of new base metal alloys requires welding wires and electrodes capable of meeting the materials’ changing mechanical requirements — increased strengths and higher impact toughness, for example. The classification gives you more filler metal options to choose from for these applications. 

2) To better define the performance capabilities of existing products. Filler metal manufacturers can showcase the full range of mechanical properties a product can provide after confirming it through testing. In the earlier example, a product may also offer impacts of 20 ft-lb. at -50 degrees Fahrenheit under A5.36.

1) The introduction of new welding wire and electrode types for more applications In short, the A5.36 specification allows for:

2) The use of greater selections of shielding gases

3) More options for filler metal strength levels

4) More flexibility with impact properties

5) More flexibility with heat treatment conditions (e.g., as welded or post-weld heat treated)

Note, the introduction of the A5.36 specification does not preclude the continuation of A5.20, A5.29, A5.18 or A5.28. These are popular specifications widely written into welding procedures and will continue to be used. 

Close-up of welder welding on steel frame

Knowing a filler metal with an A5.36 open classification provides improved 
toughness potentially reduces the need to carry out additional qualification 
testing based on new materials and welding requirements. 

 Interpreting an A5.36 open classification
The A5.36 specification utilizes distinct designators within its open classification system compared to a fixed AWS classification. Comparing the two can bring some clarity.

Consider an AWS E71T-1CJ H4 gas-shielded flux-cored (FCAW) carbon steel wire  with a fixed classification under A5.20. The designators are as follows:

1) E signifies the product is an electrode.

2) 70 indicates a tensile strength of 70 ksi.

3) 1 signifies the wire’s capability to weld in all positions. 

4) T means it’s a tubular wire.

5) 1 signifies it is a gas-shielded rutile-based slag with good operating characteristics. 

6) C means the wire requires 100 percent carbon dioxide shielding gas.

7) J designates a CVN toughness of 20 ft-lb. at -40 degrees Fahrenheit.

8) H4 shows the wire has 4ml of diffusible hydrogen per 100g of weldment. 

Under the A5.36 specification, the same wire could be classified as E71T-1-C1A5-CS2-H4 or E71T-1-C1P5-CS2-H4. Each of the designators shared with the fixed classifications remain the same. This wire can still offer 70 ksi tensile strength in all-positions using 100 percent carbon dioxide (indicated by C1 in the classification). Here’s what’s different:

1) A5 indicates the wire can offer CVN toughness of -20 ft-lb. at -50 degrees Fahrenheit in the as-welded condition.

2) P5 signifies it provides CVN toughness of -20 ft-lb. at -50 degrees Fahrenheit in the PWHT condition.

3) CS2 explains the weld deposit chemistry, which meets the lower Mn requirements of the A-No. 1 Analysis Group in the ASME, Boiler and Pressure Vessel Code, Section IX Welding and Brazing Qualification, QW-422. 

Low-alloy products follow the same designators as a fixed classification for weld deposit chemistry, including Ni1, Ni2, K2 and K3. 

To add the A5.36 classification to a spec sheet or label for either carbon or low-alloy products, filler metal manufacturers must test their product to prove these mechanical properties.

The positives and negatives
Knowing a filler metal with an A5.36 open classification provides improved toughness potentially reduces the need to carry out additional qualification testing based on new materials and welding requirements. 

A5.36 welding wires and electrodes will still retain their fixed classifications to help avoid issues with existing welding procedures. The new open classification also aligns more closely with European standards for filler metals (e.g., ISO and EN). 

Having so many classifications on a spec sheet or label, however, may create confusion. As with any welding wire or electrode, when in doubt, contact your welding distributor or filler metal manufacturer with questions.