GB24187冷間引抜精密単一溶接鋼管

Outer diameter

Common precision

High precision

＜4.76

±0.08

±0.05

4.76-8.00

±0.12

±0.07

＞8.00-12.00

±0.16

±0.10

＞12.00

±0.20

±0.12

Wall thickness

Permissible deviation

＜0.70

±0.05

≥0.70

±0.07

Length

Allowable deviation

≤2000

+4

0

＞2000-5000

+7

0

＞5000-8000

+10

0

Category

C

Si

Mn

P

S

Cold rolled low carbon steel strip

≤0.08

≤0.03

≤0.30

≤0.030

≤0.030

Cold rolled ultra low carbon steel strip

≤0.008

≤0.03

≤0.25

≤0.020

≤0.030

Thickness

/mm

Tensile Strength

Rm/MPa

Yield Strength

Reh/MPa 

Elongation

A/%

0.25~＜0.35

≥270

≥32

0.35~＜0.50

≥34

≥0.50

≥36

a Replace with RP0.2 when the yield phenomenon is not obvious.

b Sample type of sample number D14 in GB/T 228-2002.

Thickness

/mm

Tensile Strength

Rm/MPa 

Yield Strength

Reh/MPa

Elongation

A/%

≤0.50

≥280

130~250

≥38

＞0.50

≥40

a Replace with RP0.2 when the yield phenomenon is not obvious.

b Sample type of sample number P14 in GB/T 228-2002.

Category

Tensile Strength

Rm/MPa

Yield Strength

Reh/MPa

Elongation

A/%

Ordinary steel pipe(MA)

≥270

≥180

≥14

Soft steel tube(MB)

≥230

150~220

≥35

a Replace with RP0.2 when the yield phenomenon is not obvious.

b Sample type of sample number S7 in GB/T 228-2002.

NO

Inspection Items

Sampling Method ,Test Methods

Sampling Quantity

1

Chemical composition

GB/T 223, GB/T 4336, GB/T 20066

GB/T 20123, GB/T 20126

Take 1 samples per furnace

2

Mechanical property

GB/T 228

Take 1 samples per batch

3

Flattening test

GB/T 246

Take 1 samples per furnace

4

Expansion test

GB/T 242

Take 1 samples of two steel pipes per batch

5

Bending test

GB/T 244

Take 1 samples per batch

6

Hydraulic test

GB/T 241

Take 1 samples per batch

7

Flared test

Appendix A

Take 1 samples per batch

8

Requirements for the inner surface of high definition clean steel pipe

Appendix B

Consultation between Supply and demand parties

9

Outer coating

Appendix C

Consultation between Supply and demand parties

10

Residuals of internal surface cleanliness

Appendix D

Consultation between Supply and demand parties

Out

Dimensions

D

Single-Layer expansion diameter

D₁

Double-Layer expansion diameter

D₂

The minimum length of Double-Layer expansion diameter

L

Inner diameter of double-lay expansion

D₃

The inner diameter of flaring round corner

r

3.18

4.5

5.0

1.0

The maximum

size :(D-2S)+0.25

The minimum size:(D-2S)-0.50

1.0±0.3

4.00

5.4

6.0

1.0

4.76

6.3

7.0

1.0

5.00

6.6

7.3

1.0

6.00

7.7

8.4

1.0

6.35

8.1

8.8

1.0

7.94

10.1

10.7

1.6

8.00

10.1

10.8

1.6

9.53

11.8

12.5

1.6

10.00

12.3

13.0

1.6

12.00

14.6

15.2

1.6

14.00

17.0

17.5

2.1

15.88

19.1

19.6

2.1

16.00

19.2

19.7

2.1

18.00

21.5

22.0

2.1

Only to choose one from D₂ and D₃

Label

Type

The time of anti-corrosion

Cu

Copper-coated iron

--

Zn

Galvanized pipe

48h

Label

Type

Typical appearance

The time of anti-corrosion

A

Bright

Transparent, sometimes with a slight blue light

6h

B

Bleach

Transparent and a little iridescence

24h

C

Iridescence

The iridescence of partial yellow

72h

D

Dark color

Oliver green with brown and bronze

96h

E

Composite

Dark

200h

Note: This table is based on chromate conversion film, the use of other treatment methods can be negotiated by both parties