| Grade of Steel: JIS G 3445 Grade STKM 11 A, STKM 12 A, B, STKM 13 A | Dimension tolerance: Outside Dimension
Size Range: OD 17.3 mm. - 50.8 mm. (max)
Thickness: 0.45 mm. - 20 mm. |  | | Grade | Designation | Tensile Strength | Yield point or proof stress | Elongation % | Flattening Strength | Bending strength | No.4
No.11
No.12
test pieces Longitudinal direction | No.4
No.5
test pieces Transverse direction | Distance between flat plates (H)
(D is outside dia. of the tube) | Bend angle | Inside radius
(D is outside dia> of the tube) | | Grade 11 | A | STKM 11 A | 30 min. {294} min. | - | 35 min. | 30 min. | 1/2 D | 180° | 4 D | | B | STKM 12 A | 35 min. {343} min. | 18 min. {177} min. | 35 min. | 30 min. | 2/3 D | 90° | 6 D | | Grade 12 | A | STKM 12 B | 40 min. {392} min. | 28 min. {275} min. | 35 min. | 20 min. | 2/3 D | 90° | 6 D | | B | STKM 12 C | 48 min. {471} min. | 36 min. {353} min. | 20 min. | 15 min. | - | - | - | | Grade 13 | A | STKM 13 A | 38 min. {373} min. | 22 min. {216} min | 30 min. | 25 min. | 2/3 D | 90° | 6 D |
TECHNICAL SPECIFATION REFERENCESRound, Square, & Rectangular Hollow SectionsASTM A-500 Specification
Excerpts from ASTM A-500 Specification | | Tolerance in Outside Dimensions | Largest Outside Dimension, across flats, inch (mm.) | Tolerances, Plus and minus, inch (mm.) | | 2 1/2 (63.5) and under | 0.020 (0.50) | | Over 2 1/2 to 3 1/2 (63.5 to 88.9), include (Tolerances include allowance for convexity or concavity) | 0.025 (0.64) |
| Tolerance in Wall Thickness | Plus and minus 10% of nominal thickness, exclusive of weld area |
| Tolerance in Length | Plus 2 inch (50.8 mm.) and minus zero on ordered lengths. (This is standard tolerance).
If any closer tolerance is desired, please be sure to specify that in your inquries or orders). |
| Tolerance in Length | Specified Dimension of Longest Side. Inch (mm.) | Maximum Twist in 3 ft., in. | Maximum Twist in 1 m. mm. | | 1 1/2 (38.1) and under | 0.050 | 1.39 | | Over 1 1/2 to 2 1/2 (38.1 to 63.5), incl. | 0.062 | 1.72 | | Over 2 1/2 to 4 (63.5 to 101.6), incl. | 0.075 | 2.09 |
Chemical Composition
(Heat Analysis) | | ASTM A-500 Specification Grade A | Manufacturer Standard | | Carbon, max., % | 0.26 | 0.26 | | Manganese, max., % | - | - | | Phosphorus, max., % | 0.04 | 0.04 | | Sulphur, max., % | 0.05 | 0.05 |
| Mechanical Properties | | ASTM A-500 Specification Grade A | Thai Koon Steel Standard | | Tensile strength, | 45,000 | 2700 N/ mm^2 min. | | min, psi (MPa) | (310) | - | | Yield point, min., psi (MPa) | 39,000 | 170 N/ mm^2 min. | | Elongation (Gauge length 2") | (269) | 20% min. |
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JIS G 3445 STKM and ASTM
