Grade B21 Cr-Mo-V - ASTM A540/540M-2015

Grade	Grade B21
Other Names
Corresponding Standard	ASTM A540/540M-2015 Alloy-Steel Bolting for Special Applications
Classification	Alloy Steel

Grade B21 Chemical Element Composition Content (%)

Component	C	Si	Mn	P ^①	S ^①	Cr	Mo	V
Minimum Value	0.36	0.15	0.45	-	-	0.8	0.5	0.25
Maximum Value	0.44	0.35	0.7	0.025	0.025	1.15	0.65	0.35

Grade B21 Mechanical Properties

	Tensile Strength σ_b Mpa	Specified Plastic Yield Strength Rp_0.2 Mpa	Elongation or Extension Rate δ %	Reduction of Area ψ %	Hardness HBW
Class 5, d≤50	≥825	≥725	≥15	≥50	241~285
Class 5, 50＜d≤150	≥795	≥690	≥15	≥50	248~302
Class 5, 150＜d≤205	≥795	≥690	≥15	≥50	255~311
Class 4, d≤75	≥930	≥825	≥13	≥45	269~331
Class 4, 75＜d≤150	≥930	≥825	≥13	≥45	277~352
Class 3, d≤75	≥1000	≥895	≥12	≥40	293~352
Class 3, 75＜d≤150	≥1000	≥895	≥12	≥40	302~375
Class 2, d≤100	≥1070	≥965	≥11	≥40	311~401
Class 1, d≤100	≥1140	≥1035	≥10	≥35	321~429

GradeB21 Corresponding Standards(Same grade name, different standards)

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