STK400 कार्बन स्ट्रक्चरल स्टील ट्यूब

CHEMICAL COMPOSITION %  max

Steel grade

C

Si

Mn

P

S

STKR 400

0.25

-

-

0.04

0.04

STKR 490

0.18

0.55

1.5

0.04

0.04

MECHANICAL PROPERTIES min

Steel grade

Tensile strength Mpa

Yeild point or proof stress Mpa

Elongation %

STKR 400

400

245

23

STKR 490

490

325

23

Dimensional tolerance

Specified item and dimension

Dimensional tolerance

length of side

100mm or under

±1.5mm

over 100mm

±1.5%

Unvenness of flat plate portions

side length 100mm or under

0.5mm max

side length over 100mm

within 0.5% of side length

Angularity made by adjacent flat plate portions

±1.5°

Dimension at corner:s

3t max

Length

+ not specified

 0

Un-straightness

Within 0.3%

Wall thickness :t

Square steel tube manufacture by welding

under 3 mm ±0.3mm
3mm or over ±10%

Seamless square steel tube

under 4mm ±0.6mm
4mm or over ±15%