JIS G3445 STKM11A STKM13A ERW gelaste koolstofstalen buis voor auto-uitlaatsysteem

Chemical Composition  unit:% max

Grade

Symbol of grade

C

Si

Mn

P

S

Nb or V

11

A

STKM11A

0.12

0.35

0.60

0.040

0.040

-

12

A

STKM12A

0.20

0.35

0.60

0.040

0.040

-

B

STKM12B

C

STKM12C

13

A

STKM13A

0.25

0.35

0.30-0.90

0.040

0.040

-

B

STKM13B

C

STKM13C

14

A

STKM14A

0.30

0.35

0.30-1.00

0.040

0.040

-

B

STKM14B

C

STKM14C

15

A

STKM15A

0.25-0.35

0.35

0.30-1.00

0.040

0.040

-

C

STKM15C

16

A

STKM16A

0.35-0.45

0.40

0.40-1.00

0.040

0.040

-

C

STKM16C

17

A

STKM17A

0.45-0.55

0.40

0.40-1.00

0.040

0.040

-

C

STKM17C

18

A

STKM18A

0.18

0.55

1.50

0.040

0.040

-

B

STKM18B

C

STKM18C

19

A

STKM19A

0.25

0.55

1.50

0.040

0.040

-

C

STKM19C

20

A

STKM20A

0.25

0.55

1.60

0.040

0.040

0.15

Remarks:
1. For the tubes of Grade 15 made by electric resistance welded, the lower limit of C may be altered by agreement between the purchaser and the manufacturer.
2. For the tubes of Grade 20, Nb in combination with V may be added. In the case, the maximum content of Nb + V shall be 0.15%.
3. If necessary, alloying elements other than those in the above table may be added.

Mechanical Properties   min

Grade

Symbol of grade

Tensile strength

N/mm2

Yield point or proof strength

N/mm2

Elongation

%

11

A

STKM11A

290

-

35

12

A

STKM12A

340

175

35

B

STKM12B

390

275

25

C

STKM12C

470

355

20

13

A

STKM13A

370

215

30

B

STKM13B

440

305

20

C

STKM13C

510

380

15

14

A

STKM14A

410

245

25

B

STKM14B

500

355

15

C

STKM14C

550

410

15

15

A

STKM15A

470

275

22

C

STKM15C

580

430

12

16

A

STKM16A

510

325

20

C

STKM16C

620

460

12

17

A

STKM17A

550

345

20

C

STKM17C

650

480

10

18

A

STKM18A

440

275

25

B

STKM18B

490

315

23

C

STKM18C

510

380

15

19

A

STKM19A

490

315

23

C

STKM19C

550

410

15

20

A

STKM20A

540

390

23

Remarks:
1. As for the tubes of outside diameter of 40mm or under, the elongation value in above table shall not be applied. However, the test result shall be recorder. Further, the elongation may be specified under the agreement between the purchaser and the manufacturer.

2. 1 N/mm2 = 1MPa