Precision cold drawn black pipe and cold rolled seamless steel tube

Commodity name

Surface 

Treatment

Oiled, Galvanized, or according to the customer’s acquirement

Technique 

Cold drawn & cold rolled

Application

1hydraulic cylinder

2. automobile

3.oil drilling

4.textil machinery

5. engineering machinery

6. printing machinery

Delivery 

Conditions

1. BK (+C) 

No heat treatment after last cold forming process.

2. BKW (+LC)

After last heat treatment 

there is a light finishing pass (cold drawing)

3. BKS (+SR)

After the final cold forming process

 the tubes are stress relieve annealed.

4. GBK (+A)

After the final cold forming process 

the tubes are annealed in a controlled atmosphere.

5. NBK (+N)

After the final cold forming process 

the tubes are annealed above the upper transformation

 point in a controlled atmosphere. 

Package

1. Bundle Packing.

2. Plain end or vanished as per customer's request.

3. Wrapped in waterproof paper.

4. Sackcloth with several steel strips.

5. Pack in heavy tri-wall boxes.

C

Mn

Si

S(Max)

P(Max)

CK20

0.17-0.24

0.35-0.65

0.17-0.37

0.035

0.035

CK45

0.42-0.5

0.5-0.8

0.17-0.37

0.035

0.035

St52

≤ 0.22

≤ 1.6

≤0.55

0.025

0.025

27SiMn

0.24-0.32

1.1-1.4

1.1-1.4

0.035

0.035

Material

Tensile strength

Yield strength

Elongation

Hardness

Ck20

510 σ N/mm2

500σsN/mm2

5δs%

175HB

Ck45

660 σN/mm2

630σsN/ mm2

4δs%

207HB

ST52

580σ N/mm2

420σsN/ mm2

10δs%

190HB

27SiMn

840σ N/mm2

805σsN/ mm2

7.5δs%

230HB

30

+0.021        0

+0.038        0

+0.052       0

+0.084  

0

+0.130      

0

±5%,±10%

>30-50

+0.025      0

+0.039

0

+0.062       0

+0.100  

0

+0.160      

0

>50-80

+0.030    

0

+0.046  

0

+0.074       0

+0.120  

 0

+0.190      

 0

>80-120

+0.035    

 0

+0.054  

0

+0.087       0

+0.140  

0

+0.220      

 0

>120-180

+0.040    

 0

+0.063  

0

+0.100       0

+0.160  

 0

+0.250      

 0

>180-250

+0.046    

 0

+0.072  

0

+0.115       0

+0.185  

0

+0.290      

 0

>250-315

+0.052    

0

+0.081  

0

+0.130       0

+0.210  

 0

+0.320      

0

>315-400

+0.057

0

+0.089  

0

+0.140         0

+0.230  

 0

+0.360    

0

   Application

Cold drawn or cold rolled precision seamless steel tubes for hydraulic pressure and pneumatic services.

For Auto use,machinery use,oil cylinder tube,motorcycle shock reducer use,auto shock reducer inner cylinder,gas spring use etc.

Seamless steel pipes for low and medium pressure boiler, high pressure boiler, 

ship-building,

Liquid service, petroleum cracking, chemical fertilizer equipment,Drawing-oil-equipment and structure purposes.

1.100% PMI,Spectro Chemical Aanlysis Test for Raw Material

2.100% Dimension & Visual Examination 

3. Mechanical Properties Test Include Tension Test,Flaring Test (For Seamless tube/pipe)/ Flange Test (For Welded Pipe & Tube), Hardness Test ,Reversed Flattening Test

4.100% Hydrostatic Test or 100% NON-DESTRUCTIVE Test  (ET or UT) 

5.Radiographic Test for Welded Pipe (shall be accordance with specification,or shall be as agreed upon between the purchaser and vendor)

6.Straightness Test  (optional)

7.Roughness Test (optional)

8.Intergranular Corrosion Test(optional)

9.Impact Test (optional)

10.Grain Size Determinations (optional)

NOTES : ALL THE TESTS AND INSPECTION RESULT NEED TO BE SHOWED IN REPORTS ACCORDING TO STANDARD AND SPECIFICATION.