Double wall steel tubes

Dimension and specification Thickness （mm） Weighe （g/m） Assurance Pressure (kg/cm²） 4.76 0.70 70.28 350 6.00 0.70 91.76 350 6.35 0.70 97.75 350 7.00 0.70 108.75 350 7.14 0.70 111.17 350 8.00 0.70 126.31 350 Technical requirement ±0.08mm (±0.05mm） Thickness(mm) ±0.08mm Chemical Composition C - Max…
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Double wall steel tubes
Products
Welded

Dimension and specification

O.D （mm）

Thickness （mm）

Weighe （g/m）

Assurance Pressure (kg/cm²）

4.76

0.70

70.28

350

6.00

0.70

91.76

350

6.35

0.70

97.75

350

7.00

0.70

108.75

350

7.14

0.70

111.17

350

8.00

0.70

126.31

350

Technical requirement

O.D(mm)

±0.08mm     (±0.05mm）

Thickness(mm)

±0.08mm

Chemical Composition

C - Max 0.12%

Mn - Max 0.50%

P - Max 0.04%

S - Max 0.045%

Mechanical Properties

Tensile strength - Min 30kgf/mm²

Yield point - Min 18kgf/mm²

Elongation(50mm) - Min 25%

Hardness(HR30T) - Max 65

Expand test

take 3 samples of 200mm,expand the pipe outside dimension to larger than 25%

Internal cleanliness

partical and oil＜0.194g/㎡

Surface coating treatment type
    1)copper coating                                  
    2)copper+ Cr3+ znic/Nano
    3) copper+ Cr3+ znic+ PVF/galfan(Al-Znic)

Cross section 

 

Product Usage
opper brazed double wall steel tube is made of steel strip which is copper plated on both sides. It has widely applied for automobiles, refrigerators and the other hydraulic system industries.

Fluid Carrying System for Automobiles

Oil line tubes      Power steering tubes     Brake line tubes Sunroof tubes            

Fluid Carrying System for Refrigerators

international test standard
SAE J527b/JASO M101-94/KS R2028/GB11258-89/ASTM-A254

International test standard

International test standard / Project

GB11258-89
        (DWST)

ASTM-A254
        (DWST)

SAE J527b(DW)
        SAE J526b(SW)

JASO M101
        (DW/SW)

KS R2028
        (DW/SW)

Outside Dia.

Nominal±0.10

Nominal±0.076

Nominal±0.076

Nominal±0.1

Nominal±0.1

Wall Thickness

Nominal±0.12

Nominal±0.076

Nominal±0.076

Nominal±0.1

Nominal±0.1

Appearance

No harmful
defect

No harmful
defect

No harmful
defect

No harmful
defect

No harmful
 defect

Chemical
        Composition

C

0.05-0.11

0.05-0.15

0.08-0.13

0.12max

0.12max

Mn

0.25-0.50

0.27-0.63

0.30-0.60

0.50max

0.50max

P

0.035max

0.035max

0.035max

0.040max

0.040max

S

0.035max

0.035max

0.035max

0.045max

0.045max

Mechanical
Properties

T.S

290MPa min

290MPa min

290MPa min

30kg/mm² min

30kg/mm² min

Y.P

180MPa min

172MPa min

172MPa min

18kg/mm² min

18kg/mm² min

E.L

14-40%

25% min

14-40%

25% min

25% min

HR30T

Not mentioned

Not mentioned

65max

65max

65max

Corrosion
Resistance
 (Hours)

　

Not mentioned

Not mentioned

Not mentioned

white

Red

white

Red

Zn 8μm

72

192

72

192

Zn 13μm

72

288

72

288

Zn 25μm

72

480

72

480

Zn+PVF

-

3000

-

3000

Pressure
Proof Test
(kg/mm²）

　

　

　

　

DW

SW

DW

SW

under8

P=2St/D

P=2St/D

P=2St/D

350

250

350

250

8.0-10.0

S=110MPa

S=110MPa

S=138MPa

250

200

250

200

　

　

　

　

　

　

　

　

Flattening
        ＆Bending Tset

Not mentioned

Not mentioned

Not mentioned

DW

SW

DW

SW

No

Not

No

Not

crack

mentioned

crack

mentioned

Expansion/Flaring
        Test(20%)

No crack,flaw

No crack,flaw

No crack,flaw

No crack,flaw

No crack,flaw

Bend Test

under8.00
8.00-10.00

No crack,flaw
atR=1.5D
 R=2.5D
Bending

No crack,flaw
atR=1.5D
 R=2.5D
  Bending

No crack,flaw
atR=1.5D
 R=2.5D
 Bending

No crack,flaw
 atR=1.5D
 R=2.5D
Bending

No crack,flaw
 atR=1.5D
R=2.5D
Bending

Flattening Tset

No crack,flaw

Not mentioned

Not mentioned

No crack，flaw

No crack，flaw

 

     

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