Carbon Steel
The workhorse grade family. Covers the majority of industrial pressure service from refinery process to pipeline pressure to waterworks. Five major grades each have a distinct application envelope.
A105 Forged Carbon
36 ksi minimum yield, 70 ksi tensile. The default forged carbon flange grade for room-temperature pressure service. Covers ASME B16.5 catalog flanges in all standard pressure classes. Minimum design metal temperature minus 20 degrees F without impact testing. Above 800 degrees F, ratings derate sharply per ASME B16.5 P-T tables.
A350 LF2 / LF3
Carbon and carbon-nickel forged grades with mandatory charpy impact testing. LF2 covers minimum design metal temperature to minus 50 degrees F. LF3 contains 3.5 percent nickel for service to minus 150 degrees F. Both are dimensionally identical to A105 and substitute where the project specifies low-temperature pressure service.
A516 Grade 70
Pressure-rated plate. 38 ksi yield, 70 ksi tensile. The default plate for blind and ring flanges in pressure service. Normalized when section thickness exceeds 1.5 inch. Charpy impact testing optional for low-temperature service. Domestic-melt heat lots available for BABA and AIS projects.
A36 Structural Plate
36 ksi yield structural plate. Used on AWWA C207 ring flanges and on non-pressure structural flange applications. Not pressure-qualified for ASME service. A36 should not substitute for A516-70 on pressure drawings.
A694 High-Yield Pipeline
Forged carbon with elevated yield strengths matched to API 5L X-grade pipe. Grade designators F42 through F70 where the number is the minimum yield in ksi. MSS SP-44 pipeline flanges are the typical application. Normalize-and-temper or quench-and-temper heat treated. Charpy impact testing mandatory above F52.