GB/T 24591 20GJ Seamless Steel Tubes for High Pressure Feedwater Heater, ASTM A556/A556M, EN 10216-2, ASME SA209, 20GJ (SA556B2, SA556C2, P235GH), 20MnGJ (SA556B2, SA556C2, P235GH), 15MoGJ (16Mo3, T1a)

GB/T 24591 Seamless Steel Tubes for High Pressure Feedwater Heater

Standard: GB/T 24591
Equivalent Standards: ASTM A556/A556M, EN 10216-2, ASME SA209

Material: 20GJ
Equivalent Material: SA556B2, SA556C2, P235GH

Chemistry Composition

Grade	C	Si	Mn	P	S	Cr	Ni	Cu	Mo	V
20GJ	0.17%-0.23%	0.17%-0.37%	0.35%-0.65%	0.025% max	0.020% max	0.25% max	0.25% max	0.20% max	0.15% max	0.08% max
20MnGJ	0.17%-0.25%	0.17%-0.37%	0.70%-1.06%	0.025% max	0.020% max	0.25% max	0.25% max	0.20% max	0.15% max	0.08% max
15MoGJ	0.12%-0.20%	0.17%-0.37%	0.40%-0.80%	0.025% max	0.020% max	0.30% max	0.30% max	0.20% max	0.25%-0.35%	-

Mechanical Properties

Grade	Tensile Strength , MPa	Yield Strength, MPa	Elongation, %	Hardness, HRB	Hardness, HV
20GJ	410 min	245 min	30 min	85 max	163 max
20MnGJ	480 min	280 min	30 min	89 max	178 max
15MoGJ	450 min	270 min	30 min	89 max	178 max

Outside Diameter & Tolerance (OD is normally from 12mm to 32mm)

Outside Diameter, mm	Tolerance, mm
OD＜25	±0.10
OD≥25	±0.15

Wall thickness & Tolerance (WT is normally from 1.5mm to 4mm)

Wall Thickness, mm	Tolerance, %	Tolerance, %
WT, All	±10	+20/-0

GB/T 24591 specifies the size, shape, weight and allowable deviations, technical requirements, test methods, inspection rules, packaging, marking and quality certificates of seamless steel tubes for high-pressure feedwater heaters. GB/T 24591 is applicable to straight and U bending seamless steel tubes for high-pressure feedwater heaters.
GB/T 24591规定了高压给水加热器用无缝钢管的尺寸、外形、重量及允许偏差、技术要求、试验方法、检验规则、包装、标志和质量证明书。GB/T 24591适用于高压给水加热器用直管及U形无缝钢管。

Manufacture: tubes shall be made by the seamless process and shall be cold drawn.
Heat Treatment: cold-drawn tubes shall be heat treated after the final
cold-draw pass at a temperature of 1200°F [640°C] or higher to ensure ductility satisfactory for rolling into tube sheets and to meet mechanical properties as specified. If stress-relief anneal of the U-bends is specified, the anneal shall consist of heating the bent portion within a range of 1100 to 1200°F [585 to 640°C].
Inspection & Test: tension test, flattening test, flaring test, hardness test, NDT, surface inspection and dimension check.

Length: 11800mm; 12000mm; 16000mm; 18000mm; 20000mm; and so on.
Max length: 27000mm, also U bending can be offered.

Keyword: superheater steel tube, feedwater steel tube, ASTM A556, ASME SA556

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