Some questions regarding GB/T13401-2017
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In clause 4.5 of the new draft GB/T13401-2017, \"For fittings in the austenitic stainless steel material category, they can be ordered according to the dual-mark material grades of SF304/SF304L, SF304/SF304H, SF316/SF316L, SF316/SF316H, SF321/SF321H, and SF347/SF347H.\" In this case, the fittings shall meet the chemical composition and mechanical property requirements for each material grade. ” How should dual-marking materials be understood in this context – is it meant that one fitting uses two different materials? Is this a composite material?
This post was last edited by lovepds on 2017-3-30 at 17:56; it is a material with two grades, essentially one type of material. This material meets the chemical composition and mechanical properties requirements of these two grades; the standards provide clear explanations. Fittings must comply with the chemical composition and mechanical property requirements of each material grade.
Its chemical composition meets that of 304L, while its mechanical properties meet those of 304. . . You can tell just by looking at their standard values; in this way, there is overlap, and thus both of these grade specifications are considered qualified. .
Thank you very much for your reply. I have another question: is there a steel pipe that matches this? For example, what standard is used for 304/34L steel pipes?
If it is for American standards, ASTM A312 can be used; for Chinese standards, GB/T14976 should be used
Is this type of steel pipe with two different grades available in the market?