st.37.4 din2391 cold drawn seamless precision 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 formingprocess 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.

40*50

90*110

140*170

190*215

40*55

95*110

145*170

190*220

50*60

95*115

150*170

190*225

50*65

100*110

150*175

200*220

55*70

100*114

150*180

200*225

60*70

100*115

155*180

200*230

60*75

100*120

160*175

200*245

60*78

100*125

160*180

200*250

63*73

105*125

160*185

220*250

63*75

110*125

160*190

220*270

63*76

110*130

160*195

225*250

63*78

115*130

165*190

240*273

65*80

115*135

165*205

250*290

70*80

120*140

170*200

250*300

70*82

125*140

180*200

260*300

70*85

125*145

180*205

280*323

70*90

125*150

180*210

280*355

75*90

130*150

180*215

300*350

80*92

130*155

180*220

200*213

80*95

130*160

185*205

200*216

80*100

135*160

185*215

250*266

85*100

140*160

185*220

90*105

140*165

190*210

OD

GB/T3639(GB8713)

DIN2391(EN10305)

Our Tolerence

Best Quality

4-30mm

±0.10mm

±0.08mm

±0.05mm

±0.02mm

31-40mm

±0.15mm

±0.15mm

±0.05mm

±0.03mm

41-50mm

±0.20mm

±0.20mm

±0.05mm

±0.03mm

51-60mm

±0.25mm

±0.25mm

±0.08mm

±0.03mm

61-70mm

±0.30mm

±0.30mm

±0.10mm

±0.05mm

71-160mm

±0.30mm

±0.30mm

±0.10mm

±0.05mm

Tolerance in WT

±0.12mm

±0.10mm

±0.05mm

±0.03mm

Process

Diameter

Length

Precision

Inner Hole Roughness

Cold Rolled

30-100mm

≤12 m

H8-H10

0.4-1.6

Cold Draw

30-250mm

≤12 m

H8-H10

0.8-1.6

Honing

40-500mm

≤12 m

H8-H9

0.4-0.8

Rolling

40-400mm

≤7 m

H8

0.4

Inner Diameter

H8

H9

H10

30mm

±0.033

±0.052

±0.084

5-30mm

30-50mm

±0.039

±0.062

±0.100

±0.080

50-80mm

±0.046

±0.074

±0.120

80-120mm

±0.054

±0.087

±0.140

120-180mm

±0.063

±0.100

±0.160

180-250mm

±0.072

±0.115

±0.185

250-315mm

±0.081

±0.130

±0.210

315-400mm

±0.089

±0.140

±0.230

   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.