The Grade L7M Stainless Steel Bolting for Low-Temperature Service

The ASTM A320 Grade L7M specification covers stainless steel bolting materials for low temperature service. This standard covers rolled, forged, or strain hardened bars, bolts, screws, studs, and stud bolts used for pressure vessels, valves, flanges, and fittings. Like the ASTM A193 specification, unless otherwise specified, the 8UN thread series is specified on fastener larger than 1” in diameter.

L7M

Hex bolts, screws, stud bolts, double ended studs, Stud for foundation, wind energy bolts, Fasteners for wind turbines

Property class	Chemical composition
	C.	Mn.	Si.	P.	S.	Cr.	Ni.	Mo.	V.	Ti.
L7M	0.38---0.48	0.75---1.00	0.15---0.35	0.035 max.	0.040 max.	0.80---1.10	-	0.15-0.25	-	-

Class, Diameter In	Heat TreatmentB	Tensile Strength, min, ksi [MPa]	Yield Strength, min, ksi [MPa] (0.2 % offset)	Elongation in 2 in. or 50 mm min, %	Reduction of Area, min, %	Hardness max
21⁄2 [65] and under	quenched and tempered	100 (690)	105 (725)	16	50	321 HBC or 35 HRC