About A514 GR B|Quench and tempered alloy plate. 100 KSI minimum yield strength. Also sold under the trade name T-1 (by US Steel). This is the high end of structural plate. Roughly 3x the yield strength of
A36. Used for heavy equipment, pressure-critical structures, bridge components, and military applications. Requires careful welding procedures with preheat, low-hydrogen consumables, and controlled interpass temperatures. Machines harder than A36 but not terribly since it's still a low-carbon base. Good subzero toughness. Expensive. Compare to A36 (1/3 the strength, much cheaper, easier to fabricate),
A572 GR50 (middle ground in strength), and
AR400F (similar hardness but optimized for wear, not structural strength).
