To my considerable surprise, ASTM A500, Grade C, is not included in Table 3.1, Group II. Procedure qualification tests are therefore required according to Clause 3.3. ANSI/AWS B2.1:1998, Table D1, classifies ASTM A55, Grade C, as a Material number 1, group number 1.
Why is Grade C not included in Table 3.1?
Not all materials are considered to be 'prequalified" by the D1 Committee. When the committee considers a material for this table, many factors are considered. One of the most important factor is the ease of weldability. Materials in this table most generally have a proven track record and when combined with the entire code for "prequalification", work well with the joint designs, process essential variables, preheat tables, filler metal tables, and design application rules.
Please consider this as my personal opinion and not that of the D1 Committee.
Allen Sindel, 3rd Vice Chairman D1 Committee.
Mr. Sindel,
Thank you for your reply. I recognize that materials selected for prequalified procedures must be readily weldable and have a proven track record. We have extensive experience with A500, Grade C, in Canada where it is often used in lieu of our CSA G40.21, Grade 350W, and we have not had any problems welding it. The carbon equivalent and mechanical properties, and the common usage in the US and Canada, should make it a candidate for inclusion in future editions of AWS D1.1 I hope.
Stig Skarborn
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