GB/T13793 10#15#20# Q195 Steel Pipes with a longitudinal Electric Resistance Weld

Outer Diameter(D)

General Precesion(PD.A)^a

Higher Precision(PD.B)

High Precision(PD.C)

5-20

±0.30

±0.15

±0.05

﹥20-35

±0.40

±0.20

±0.10

＞35-50

±0.50

±0.25

±0.15

＞50-80

±1%D

±0.35

±0.25

＞80-114.3

±0.60

±0.40

＞114.3-168.3

±0.70

±0.50

＞168.3-219.1

±0.80

±0.60

＞219.1-711

±0.75%D

±0.5%D

^a Not apply for steel pipe for roller of belt conveyor

Wall Thickness(t)

General Precesion(PD.A)^a

Higher Precision(PD.B)

High Precision(PD.C)

Non-uniform Wall Thickness^b

0.50-0.70

±0.10

±0.04

±0.03

≤7.5%t

＞0.70-1.0

±0.05

±0.04

＞1.0-1.5

±0.06

±0.05

＞1.5-2.5

±10%t

±0.12

±0.06

＞2.5-3.5

±0.16

±0.10

＞3.5-4.5

±0.22

±0.18

＞4.5-5.5

±0.26

±0.21

＞5.5

±7.5%t

±5.0%t

^a Not apply for steel pipe for roller of belt conveyor

^b Not apply for General Precesion steel tube. Non-uniform Wall Thickness means the difference between maximum and minimum values of measured wall thickness on the same cross section.

Outer Diameter(D)/mm

Bending/(mm/m),No more than

General Precesion(PD.A)

Higher Precision(PD.B)

High Precision(PD.C)

＞16

1.5

1.0

0.5

General Precesion

Higher Precision

High Precision

+0.50

-0.20

+0.50

-0.05

+0.20

-0.05

Wall thickness t/mm

1.2

.14

1.5

1.6

1.8

2.0

2.2

2.5

2.8

3.0

3.2

3.5

Coefficient c

A

1.106

1.091

1.085

1.080

1.071

1.064

1.058

1.051

1.045

1.042

1.040

1.036

Coefficient c

B

1.085

1.073

1.068

1.064

1.057

1.051

1.046

1.041

1.036

1.034

1.032

1.029

Coefficient c

C

1.064

1.055

1.051

1.048

1.042

1.038

1.035

1.031

1.027

1.025

1.022

1.020

Wall thickness t/mm

3.8

4.0

4.2

4.5

4.8

5.0

5.4

5.6

6.0

6.5

7.0

8.0

Coefficient c

A

1.034

1.032

1.030

1.028

1.027

1.025

1.024

1.023

1.021

1.020

1.018

1.016

Coefficient c

B

1.027

1.025

1.024

1.023

1.021

1.020

1.019

1.018

1.017

1.016

1.015

1.013

Coefficient c

C

1.020

1.019

1.018

1.017

1.016

1.015

1.014

1.014

1.013

1.012

1.011

1.010

Wall thickness t/mm

9.0

10.0

11.0

12.0

12.7

13.0

14.2

16.0

17.5

20.0

Coefficient c

A

1.014

1.013

1.012

1.011

1.010

1.010

1.009

1.008

1.007

1.006

Coefficient c

B

1.011

1.010

1.009

1.008

1.008

1.008

1.007

1.006

1.006

1.005

Coefficient c

C

1.008

1.008

1.007

1.006

1.006

1.006

1.005

1.005

1.004

1.004

Steel Grade

Lower yield strength R_e1./MPa

Tensile strength

R_m/MPa

Elongation

A/%

D≤168.3mm

D＞168.3mm

≥

08.10

195

315

22

15

215

355

20

20

235

390

19

Q195^b

195

315

15

20

Q215A,Q215B

215

335

Q235A,Q235B,Q235C

235

370

Q275A,Q275B,Q275C

275

410

13

18

Q345A,Q345B,Q345C

345

470

Q390A,Q390B,Q390C

390

490

19

Q420A,Q420B,Q420C

420

520

19

Q460C,Q460D

460

550

17

Weight grade of galvanized layer

Requirement

The total weight of zinc coating per unit area of the inner and outer surfaces

/(g/㎡)

no less than

A

Inside and outside surface

500

B

Inside and outside surface

400

C

Inside and outside surface

300

Number

Test items

Test frequency

Sampling quantity

1

Smelting analysis

1/furnace

1

2

Finished product analysis

1/furnace

1

3

Tensile test

1/batch

1

4

Weld tensile test

1/batch

1

5

Impact test

1/batch

2 groups in a time, 3 samples in a group

6

Flattening test

1/batch

1 sample on 2 pipes in each batch

7

Bending test

1/batch

1 sample on 2 pipes in each batch

8

Flaring test

1/batch

1 sample on 2 pipes in each batch

9

Hydraulic test

All

All

10

Ultrasonic testing

All

All

11

Eddy current testing

All

All

12

Galvanized layer uniformity test

1/batch

1/batch

13

Galvanized weight determination

1/batch

1/batch

14

Galvanized layer adhesion test

1/batch

1/batch