440A Grade has a a slightly lower percentage of carbon than other 440 grades. This material is not readily available like 440C.
Specifications:
UNS S44002, ASTM A276, ASTM A314, ASTM A473, ASTM A580, ASTM f899, QQ-S-763
Applications:
valve components, ball bearings, chisels, surgical equipment, knife blades, valve seats.