GB/T 3639 20 Seamless cold-drawn or cold-rolled steel tubes for precision applications, Precision Steel Tube, Power Steering, HPL Tube, Steel tubes for precision applications Part 1: Seamless cold drawn tubes, cold drawn seamless steel tubing, DIN-2391 sheet 2 steel grade st45 cond. nbk, AMG-69107, IU 920004, steel tube for safety system, steel tube for shock absorber, steel tube for steering system, precision steel tubes for automotive, mounting ring, container cylinder, inner cylinder, hollow piston rod, steering cylinder, inflator tube, camshafts, end forming set frames, IP beams, Engine Cradles, Anti-roll bars, seat back frames, Rear arms, Torsion beams, Stabiliser bars, Door beams, A-Pillars, EN 10305-1, NF 699, DIN 2391, ASTM A519, GOST 9567-75, NBR 8476, BS 6323 Part 4, NF A49-330-85, BS 6323-4, NF A49-310, UNI 6403

GB/T 3639 Seamless cold-drawn or cold-rolled steel tubes for precision applications

Standard: GB/T 3639
Equivalent Standards: EN 10305-1, NF 699, DIN 2391, ASTM A519, GOST 9567-75, NBR 8476, BS 6323 Part 4, NF A 49-330-85, BS 6323-4, NF A 49-310, UNI 6403

Material: 20
Equivalent Materials: E255

Chemistry Composition

C, %	Si, %	Mn, %	P, %	S, %	Cr, %	Ni, %	Cu, %
0.17-0.23	0.17-0.37	0.35-0.65	0.025 max	0.025 max	0.25 max	0.30 max	0.25 max

Mechanical Properties

Tensile Strength , MPa	Yield Strength, MPa	Elongation, %	Delivery Condition
550 min	-	5 min	+C
520 min	-	8 min	+LC
520 min	375 min	12 min	+SR
390 min	-	21 min	+A
440-570	255 min	21 min	+N

GB/T 3639 specifies the classification, code, shape, weight and allowable deviation, technical requirements, test methods, inspection rules, packaging, marking and quality certificate of cold drawn or cold rolled precision seamless steel tubes. GB/T 3639 is suitable for manufacturing cold drawn or cold rolled precision seamless steel tubes with special dimensional accuracy and high surface quality requirements, such as mechanical structures, hydraulic equipment, and auto parts.
GB/T 3639规定了冷拔或冷轧精密无缝钢管的分类、代号、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 3639适用于制造机械结构、液压设备、汽车零部件等具有特殊尺寸精度和高表面质量要求的冷拔或冷轧精密无缝钢管。

Manufacture: the tubes shall be manufactured from hot finished seamless tubes by cold drawing or other suitable processes.
Delivery Condition: cold drawn (hard) as +C, cold drawn (soft) as +LC, cold drawn and stress relieved as +SR, annealed as +A, normalized as +N.
Inspection & Test: chemistry composition analysis, tensile test, flattening test, flaring test, NDT, surface inspection and dimension check.

Length: 2000mm; 6000mm; 10000mm; 12000mm; and so on.
Further process: cutting, deformation.

Keyword: precision steel tube, GB/T 3639, precision steel tube, high precision, cng tube, HPL Tube

Home | About Us | Product | Know How | Contact Us