Socket Head Cap Screw ASME B18.3, Alloy Black

Socket head cap screws to ASME B18.3 in alloy steel, heat treated per ASTM A574 (core hardness Rockwell C 38–43, 12.9-class strength), black oxide finish. Hex socket drive for high-torque assembly in molds, machinery and fixtures; UNC/UNF inch series from #4-40 up to 1-1/2-6.

Standard	ASME B18.3 / ASTM A574
Size	#4-40 – 1-1/2-6, UNC/UNF
Material	Alloy steel, core HRC 38–43
Finish	Black oxide, plain
Packing	Box / bulk carton

• Knurled cylindrical head with deep hex socket, low profile
• Full-thread and partial-thread bodies from stock tooling
• Hardness and decarb checked every heat-treat batch

MOQ & lead time depend on size and finish — typical batch 15–30 days after confirmation. Mill test certificate 3.1 available on request.