A668 Class K - ASTM A668/A668M-2021

Grade	A668 Class K
Corresponding Standard	ASTM A668/A668M-2021 Standard Specification for Steel Forgings, Carbon and Alloy, for General Industrial Use
Classification	Alloy Steel

A668 Class K Chemical Element Composition Content (%)

Component	P	S
Minimum Value	-	-
Maximum Value	0.04	0.025

A668 Class K Mechanical Properties

Controlling Cross Section t mm	Heat Treatment or Condition	Tensile Strength σ_b Mpa	Yield Point σ_s Mpa	Elongation or Extension Rate δ %	Reduction of Area ψ %	Hardness HBW
t≤175	Normalizing, Quenching, Tempering	≥725	≥550	≥20	≥50	212~269
175<t≤250	Normalizing, Quenching, Tempering	≥690	≥515	≥19	≥50	187~269
250<t≤500	Normalizing, Quenching, Tempering	≥690	≥515	≥18	≥48	207~269

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