JIS G3445 is Japanese Industrial Standard specifies the carbon steel tubes, hereinafter referred to as the “tubes”, used for machinery, automobiles, bicycles, furniture, appliances and other machine parts.
Carbon steel tubes for machine structural purposes.
Standards: JIS G3445
Size (mm):
Outer Dimensions: 19.05mm ~ 114.3mm
Wall Thickness:2.0mm ~ 14 mm
Length: max 16000mm
Application: Tubes used for machinery, automobiles, bicycles, furniture, appliances and other machine parts.
The main products of steel / steel grade: STKM11A, STKM12(A,B,C), STKM13(A,B,C), STKM14(A,B,C).
Packing: Bare/bundles/crates/crate protection at the both sides of tubes or as per customers’ requirements .
Painting: as requested.
Chemical Compositions(%):
| Grade | C | Si | Mn | P | S |
| STKM11A | ≤0.12 | ≤0.35 | ≤0.60 | ≤0.040 | ≤0.040 |
| STKM12A | ≤0.20 | ≤0.35 | ≤0.60 | ≤0.040 | ≤0.040 |
| STKM12B | ≤0.20 | ≤0.35 | ≤0.60 | ≤0.040 | ≤0.040 |
| STKM12C | ≤0.20 | ≤0.35 | ≤0.60 | ≤0.040 | ≤0.040 |
| STKM13A | ≤0.25 | ≤0.35 | 0.30-0.90 | ≤0.040 | ≤0.040 |
| STKM13B | ≤0.25 | ≤0.35 | 0.30-0.90 | ≤0.040 | ≤0.040 |
| STKM13C | ≤0.25 | ≤0.35 | 0.30-0.90 | ≤0.040 | ≤0.040 |
| STKM14A | ≤0.30 | ≤0.35 | 0.30-1.00 | ≤0.040 | ≤0.040 |
| STKM14B | ≤0.30 | ≤0.35 | 0.30-1.00 | ≤0.040 | ≤0.040 |
| STKM14C | ≤0.30 | ≤0.35 | 0.30-1.00 | ≤0.040 | ≤0.040 |
Mechanical Properties:
| Grade | Yield Strength (Mpa) | Tensile Strength (Mpa) | Elongation (%) |
| STKM11A | \ | ≥290 | ≥35 |
| STKM12A | ≥175 | ≥340 | ≥35 |
| STKM12B | ≥275 | ≥390 | ≥25 |
| STKM12C | ≥355 | ≥470 | ≥20 |
| STKM13A | ≥215 | ≥370 | ≥30 |
| STKM13B | ≥305 | ≥440 | ≥20 |
| STKM13C | ≥380 | ≥510 | ≥15 |
| STKM14A | ≥245 | ≥410 | ≥25 |
| STKM14B | ≥355 | ≥500 | ≥15 |
| STKM14C | ≥410 | ≥550 | ≥15 |
The tubes shall be manufactured by seamless process, electric resistance welding process, or butt welding process, and those of other grades shall be manufactured by seamless process or electric resistance welding process. The tube shall be as manufactured or as cold-finished condition, or they shall be subjected to appropriate heat treatment.
The tubes shall be practically straight. and the two ends shall be at right angles to the axis of the tube. The tubes shall be free from defects detrimental to practical use.