Big OD seamless pipe/tube

Note:

1.NAME:carbon constructional quality steel

2.Grades:20#

3.STD:GB/T699-1988

4.Characteristics AND applicant fiend:

Strength is slightly higher than Gr.15, few quenching ,no temper brittleness. With quality Cold deformation plasticity, generally usded for bending, rolling, bending and hammer processing etc. The performance of electric welding arch processing and contact welding is good, the thickness with gas welding is of small, shape is must be in strict or when use for parts with complex shape that is easily happening crack. when Cutting machining lengba, normalization is better than annealing  and generally used to manufacture parts with high toughness and less stress.

5.Chemical composition:

C:0.17-0.24

Si:0.17-0.37

Mn:0.35-0.65

S:0.035max

P:0.035max

Cr:0.25max

Ni:0.25max

Cu:0.25max

6.Machinery properties:

Tensile Strength σb (MPa):≥410(42)
Yield strength σs (MPa):≥245(25)
EL% δ5 (％):≥25
Section contractility ψ (％):≥55
Hardness:without tempering,≤156HB
Gauage Length:25mm

7.Heat treatment procedure and microstructure:

Heat treatment procedure: normalization,910degree,air cooling

Mcrostructure:ferrite + pearlite

8.Delivery status:

Deliverty with heat treatment or with heat treatment( annealing、normalization or high temperature tempering). If necessary,heat treatment by notified in the contract,or will delivery without heat treatment. 

Following as reference: