Types of Different Grades Available for Specific ASTM Material

Basically, within each type of steel, the higher the grade number, the "stronger" or more high quality and expensive the steel. Much, but not all, has to do with the chromium content. Of course everything is a trade off as far as all the other characteristics of the various grades.

Min. Tensile strength, ksi / Min. Yield Strength, ksi

WC1 65-90 / 35

WC4 70-95 / 40

WC5 70-95 / 40

WC6 70-95 / 40

WC9 70-95 / 40

WC11 80-105 / 50

C5 90-115 / 60

C12 90-115 / 60

C12A 85-110 / 60

CA15 90-115 / 60

To break down the main components in stainless steels and ferritic in particular, in a very crude and general way:

Molybdenum - more of this tends to make SS more resistant to high heat with less expansion and distortion (weladability)

Nickle - more of this adds tensile strength to SS. Also more corrosion resistant.

Chromium - more of this makes SS harder and more durable, but more brittle. Also more corrosion resistant.