The Grade 8 Carbon and Alloy Steel Nuts for Bolts of High Pressure or High Temperature Service

The ASTM A194 Grade 8 specification covers carbon, alloy, and stainless steel nuts intended for use in high-pressure and/or high-temperature service. Unless otherwise specified, the American National Standard Heavy Hex Series (ANSI B 18.2.2) shall be used. Nuts up to and including 1-inch nominal size shall be UNC Series Class 2B fit. Nuts over 1-inch nominal size shall be either UNC Series Class 2B fit or 8 UN Series Class 2B fit. High strength ASTM A194 grade 8 nuts are common in the marketplace and are often substituted for ASTM A563 grade DH nuts due to the limited availability of DH nuts in certain diameters and finishes.

8

Carbon steel Hex Nut, Heavy hex nut

Property class	Chemical composition
	C.	Mn.	Si.	P.	S.	Cr.	Ni.	Mo.	V.	Ti.
8	0.08	2.00	1.00	0.045	0.030	18.00-20.00	8.00-11.00	-	-	-

Class	Diameter, [mm]	Brinell Hardness	Rockwell Hardness
			C Scale	B Scale
8	All	126-300	32 max	60 min