Tubes for Mechanical and Automobile

Seamless Steel Tubes for Mechanical and Automobile usage for Backbone of Automobile and rear axle tube, manufacturing and processing of precision equipments, instruments and apparatus.

Tubes for Mechanical and Automobile

Standard packaging is used to prevent damage to the material during shipping. If you need custom packaging for your order, please let us know what your requirements are and we will accommodate your specific needs.

Production Standard, Grade, Steel No:

Your tubular products representative will be happy to work with you to develop the information that is required. Sunny Steel supply a 1/2 million foot inventory of carbon steel pressure tubing including boiler tubes, condenser tubes and heat exchanger tubes all made in the China.

Our carbon steel pressure tubing inventory is manufactured in accordance with ASME SA-178 A and/or ASME SA-214 in diameters of 3/4″ through 4”.


Delivery Condition: GBK, BKS, BK, BKW, NBK

Inspection and Test: Chemical Composition, Mechanical Properties, Visual and Dimension Test, NDT, Grain Size Test

Surface treatment: Oil-dip, Varnish, Shot Blasting

Grade and Chemical Composition (%)
Grade C Mn P≤ S≤ Si Cr Mo
1010 0.08-0.13 0.30-0.60 0.04 0.05 - - -
1020 0.18-0.23 0.30-0.60 0.04 0.05 - - -
1045 0.43-0.50 0.60-0.90 0.04 0.05 - - -
4130 0.28-0.33 0.40-0.60 0.04 0.05 0.15-0.35 0.80-1.10 0.15-0.25
4140 0.38-0.43 0.75-1.00 0.04 0.05 0.15-0.35 0.80-1.10 0.15-0.25
Typical Mechanical Properties
Grade Condition Tensile strength Yield stength Elongation
Mpa(min) Mpa(min) %(min)
1020 CW 414 483 5
SR 345 448 10
A 193 331 30
N 234 379 22
1025 CW 448 517 5
SR 379 483 8
A 207 365 25
N 248 379 22
4130 SR 586 724 10
A 379 517 30
N 414 621 20
4140 SR 689 855 10
A 414 552 25
N 621 855 20
Minimum Quantities
Special Configurations

Machining Allowances & Production Tolerances

Hollow bar is manufactured in the size ranges most frequently required by mechanical engineering manufacturing companies. However, in the case of hollow bar, the tolerance range for the outside diameter lies in the plus range, and for the inside diameter in the minus range. The wall thickness tolerance is determined by the degree of centre offset; this is due to the effect of the tolerance for the outside and inside diameter, the wall thickness and the centre offset. (See diagram below.)

In the case of mechanical tubing to ASTM A 511, the outside diameter and the wall dimensions generally lie in the centre of the tolerance range. Thus, when ordering product for machining it is important to take into account the differences in the tolerances between the hollow bar and the ASTM A 511 mechanical tubing specifications. In most cases the machining set up is based on centring the outside diameter.

Size Range

Tubular products seamless mechanical tubing is furnished in both cold-drawn and hot finished form in a wide range of sizes, from 1.375″ to 7.750″ OD and from 0.188″ to 1.625″ wall thickness.

DIN2391 ST52 Seamless Honed Tube

Seamless pipe Specification, standard and identification

Seamless pipes are extensively applied for the nuclear device, gas, petrochemical, ship building and boiler industries. Seamless pipes dominates 65% of market share in Chinese boiler industry.