The Grade B8M C2 Fasteners used for Alloy-Steel and Stainless Steel Bolting Materials for High Temperature or High Pressure Service and Other Special Purpose Applications

The Grade B8M C2 specification is heavily utilized in petroleum and chemical construction applications. The ASTM standard covers alloy steel and stainless steel bolting materials for high temperature or high-pressure service. This specification includes fasteners intended for use in pressure vessels, valves, flanges, and fittings. Although, this material is often available in national coarse (UNC) thread pitches, if being used in traditional applications, threads are specified 8 threads per inch (tpi) for diameters above one inch.

B8M C2

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.
B8M C2	0.08 max.	2.00 max.	1.00 max.	0.045 max.	0.030 max.	16.00-18.00	10.00-14.00	2.00-3.00	-	-

Class	Diameter Inch	Tensile Strength, min, ksi	Yield Strength, min, 0.2 % offset, ksi	Elongation in 4 D, min %	Reduction of Area, min %	Hardness, max
Class 2	3⁄4 and under	110	95	15	45	321 HBW or 35 HRC
	over 3⁄4 to 1 incl	100	80	20	45
	Over 1 to 11⁄4 , incl	95	65	20	45
	over 11⁄4 to 11⁄2 , incl	90	50	30	45

Class	Diameter Inch	Tensile Strength, min, ksi	Yield Strength, min, 0.2 % offset, ksi	Elongation in 4 D, min %	Reduction of Area, min %	Hardness, max
Class 2	M20 and under	760	655	15	45	321 HBW or 35 HRC
	over M20 to M24	690	550	20	45
	over M24 to M30	655	450	25	45
	over M30 to M36	620	345	30	45