CHEMICAL COMPOSITION %  max

Steel grade

C

Si

Mn

P

S

STB 340

0.18

0.35

0.30-0.60

0.35

0.35

STB 410

0.32

0.35

0.30-0.80

0.35

0.35

STB 510

0.25

0.35

1.00-1.50

0.35

0.35

Remark:
1. When the purchaser requires product analysis,the permissible deviation for the values given above shall be as specified in the Table in JIS G 032 for the seamless steel tube and likewise in Table 1 (as JIS G 3461)for the electric resistance welded steel tube.
2.Where required by the purchaser,Si may be designated as 0.1-0.35%

MECHANICAL PROPERTIES min

Steel grade

Tensile strength Mpa

Yeild point or proof stress Mpa

Elongation %

STB 340

340

175

35

STB 410

410

255

25

STB 510

510

295

25

Hardness

Steel grade

Rockwell hardness HRB(Mean value of three points)

STB 340

77max

STB 410

79max

STB 510

92max

Heat Treatment (Applicable till the end of 1990)

Steel Grade

Heat Treatment

Hot finished seamless steel tube

Cold finished seamless steel tube

Electric resistance welded steel tube other than hot finished or cold finished steel tube

Finished electric resistance welded steel tube

Fold finished electric resistance welded steel tube

STB 340

As manufactured, as required, low temperature annealing or normalizing may be performed

low temperature annealing, normalizing or full annealing

normalizing

As manufactured, However, as required ,low temperature annealing or normalizing may be performed

normalizing

STB 410

As manufactured, However, as required, low temperature annealing or normalizing may be performed

low temperature annealing, normalizing or full annealing

normalizing

low temperature annealing

STB 510

normalizing