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Austenitic Stainless Steels

Comparison of 304 or 316 and 304L or 316L type compositions and effect on corrosion resistance

As American AISI basic grades, the only practical difference between 304 or 316 and 304L or 316L is carbon content. The carbon ranges are 0.08% maximum for 304 and 316 and 0.030% maximum for the 304L and 316L types.

Comparison of grades 316 (1.4401) and 316L (1.4404/1.4432) to 316Ti (1.4571)

Grade 316Ti stainless steel has been traditionally specified by German engineers and users with the Werkstoff number 1.4571.The former steel grade in the UK was 320S31.

Comparison of composition ranges of 316 type stainless steels

The specification of bar (to BS970) and coil / plate (to BS1449) before 1983 covered two type 316 grades: a 'low' carbon with 0.03% max (316S12) and a 'standard' carbon with 0.07% max 316S16. Both had a molybdenum content in the range of 2.25-3.0 %.

Chemical compositions of AISI (ASTM/ASME) and UNS austenitic stainless steel grades

Most ASTM and ASME standards list the steel grades by their UNS (Unified Numbering system) numbers but also make reference, where appropriate to the more general AISI (American Iron and Steel Institute) grade designations. These grade numbering systems are widely used in the USA, where they originated and are recognised by most stainless steel specifiers and users.

Effect of austenitic stainless steel composition and heat treatment on cold formability

Alloying elements that help stabilize the austenitic phase reduce the tendency of the austenitic stainless steels to work harden. Nickel additions have been used traditionally to do this, but nitrogen also has a profound affect on stability of the austenite phase.

Related austenitic stainless steel grades

The table is intended to relate former BS, En, German and Swedish grade designations to the current EN steel numbers, AISI grades ('grades' in (brackets) are not a true AISI grades) and UNS (Unified Numbering System) numbers. The table is based on the 'wrought' ie long products (bars etc), flat products (plates etc) steel numbers published in EN 10088 and related standards. Castings products use different compositions and so have their own steel numbers in EN 10283. The related castings grades in both EN 10283 and BS 3100 are included in the table.

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