YB/T 4331 12CrMo Large Diameter Alloy Structural Seamless Steel Pipes for Liquid Service, 12CrMo, 15CrMo, 12Cr2Mo, 12Cr1MoV, 12Cr5Mo, 12Cr9Mo, 12Cr1Mo

YB/T 4331 Large Diameter Alloy Structural Seamless Steel Pipes for Liquid Service

Standard: YB/T 4331

Material: 12CrMo

Chemistry Composition

C, %

Si, %

Mn, %

P, %

S, %

Cu, %

Cr, %

Ni, %

Mo, %

V, %

Al, %

Nb, %

N, %

Ti, %

Zr, %

0.08-0.12

0.20-0.50

0.30-0.60

0.020 max

0.010 max

0.20 max

8.00-9.50

0.40 max

0.85-1.05

0.18-0.25

0.02 max

0.06-0.10

0.03-0.07

0.01 max

Mechanical Properties

Tensile Strength , MPa	Yield Strength, MPa	Elongation, %	Impact (KV2)/J	Hardness
585 min	415 min	20 min	40 (OD≥76mm & WT≥14mm)	HBW 185-250	HV 185-265	HRC 25 max

Outside Diameter & Tolerance

Hot Rolled	Outside Diameter, mm	Tolerance
	Outside Diameter, mm	Ordinary	Advanced
	OD＜57	±0.40mm	±0.30mm
	57≤OD≤325, WT≤35	±0.75%	±0.50%
	57≤OD≤325, WT>35	±1%	±0.75%
	325＜OD≤600	+1% or +5mm	-
	OD>600	+1% or +7mm	-
Cold Drawn	Outside Diameter, mm	Tolerance
	OD≤25.4	±0.15mm	-
	25.4＜OD≤40	±0.20mm	-
	40＜OD≤50	±0.25mm	-
	50＜OD≤60	±0.30mm	-
	OD>60	±0.50%	-

Wall thickness & Tolerance

Hot Rolled	Wall Thickness, mm	Tolerance
	Wall Thickness, mm	Ordinary	Advanced
	WT≤4.0	±0.45mm	±0.35mm
	4＜OD≤20	+12.5%/-10%	±10%
	WT>20, OD＜219	±10%	±7.5%
	WT>20, OD≥219	+12.5%/-10%	±10%
Cold Drawn	Wall Thickness, mm	Tolerance
	Wall Thickness, mm	Ordinary	Advanced
	WT≤3.0	±0.30mm	±0.20mm
	WT>3	±10%	±7.5%

YB/T 4331 specifies the classification, code, size, shape, weight, technical requirements, test methods, inspection rules, packaging, markings and quality certificates of large diameter alloy structural seamless steel pipes for fluid transportation. YB/T 4331 is suitable to the manufacture of alloy structural seamless steel pipes with outside diameter not less than 426mm for petrochemical and coal-to-oil plant process piping and other general fluid transportation.
YB/T 4331规定了流体输送用大直径合金结构钢无缝钢管的分类和代号、尺寸、外形、重量、技术要求、试验方法、检验规则、包装、标志和质量证明书。YB/T 4331适用于外径不小于426mm的石油化工、煤制油装置工艺配管及其他一般流体输送用合金结构钢无缝钢管。

Manufacture: tubes to GB/T 5310 shall be manufactured by hot rolled or cold drawn.
Heat Treatment: the tubes shall be produced by heat treated as normalizing & tempering, WT>70mm could be quenching & tempering.
Inspection & Test: chemistry composition analysis, tension test, flattening test or bending test, flaring test, hardness test, impact test, grain size grade, decarburized layer of both inside & outside, macroscopic examination, non-metallic inclusions, microstructure, NDT, surface inspection and dimension check.

Length: 4000mm; 6000mm; 9000mm; 12000mm; and so on.
Max developed length: 30 meters, also U bending, finning, studded process can be provided.
Option: shot blasting on the outside surface to remove mill scale, make the surface matte colour; surface polishing as preparation work done for further processing, for instance finning.

Keyword: GB/T 5310, High Pressure Steel Pipe, Boiler Steel Pipe, Steam Boiler Pipe, Pipeline, Piping

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