Direct Answer
The most common ASTM grades: A992 (W-shapes, Fy = 50 ksi, excellent for seismic), A500 Grade B/C (HSS rectangular and square, Fy = 46/50 ksi), A53/A500 (round pipe/HSS), A572 Grade 50 (plates and angles, Fy = 50 ksi), and A36 (plate, angles — Fy = 36 ksi, lower strength but excellent weldability). Each grade has different yield strength, tensile strength, and chemistry requirements that affect weldability and design capacity.
Full Explanation
A992 replaced A36 for W-shapes because it has a defined yield-to-tensile ratio (max 0.85) that prevents the section from being too strong for plastic hinge design in seismic applications. A36 W-shapes are still produced but are less common. For plates, A572 Gr 50 is now the default (same yield as A992 but without the Y/T ratio requirement). A36 plate is used where lower strength is acceptable or preferred for weldability. HSS: A500 Gr B (rectangular) and A500 Gr C are equivalent to Fy = 46 and 50 ksi. ASTM A1085 is a higher-quality HSS with tighter tolerances and Fy = 50 ksi — specified for critical seismic applications.
What This Means for Your Shop
Material substitution (e.g., using A36 where A572 is specified) requires engineer approval and is a code violation without it. Your material certifications must match the ASTM grade specified on the general notes sheet.
Common Mistakes
Receiving A36 plate when A572 Grade 50 was ordered, not catching it on the mill cert, and welding it with the A572 procedure. The lower yield strength A36 may be acceptable structurally, but the undocumented substitution is a code and liability issue.
Recommended Process
Train your receiving team to check mill certifications against purchase orders before accepting material. Create a simple checklist: ASTM grade, heat number, section size, and length match. Flag any discrepancy before the material enters the shop.