A335 Grade P128 K91421 - ASTM A335/A335M-2024(b)

Grade	A335 Grade P128
USA UNS	K91421
Corresponding Standard	ASTM A335/A335M-2024(b) Seamless Ferritic Alloy-Steel Pipe for High-Temperature Service
Classification	Alloy Steel

A335 Grade P128 Chemical Element Composition Content (%)

Component	C	Si	Mn	P	S	Cr	Ni	Cu	Mo	N	W	V	Nb	B	Co	Al
Minimum Value	0.12	0.2	0.3	-	-	10.5	0.1	-	0.2	0.002	1.5	0.15	0.02	0.008	1.5	-
Maximum Value	0.17	0.6	0.8	0.02	0.01	12	0.4	0.15	0.6	0.02	2.2	0.3	0.06	0.015	2.2	0.02

A335 Grade P128 Mechanical Properties

Heat Treatment or Condition	Tensile Strength σ_b Mpa	Yield Point σ_s Mpa	Elongation or Extension Rate δ %	Hardness HBW
Normalizing 1080~ 1170°C+ Tempering 760~800°C	≥650	≥490	l: ≥20	HBW: ≤265 HV: ≤280 HRC: ≤27

l=longitudinal；t=transverse

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