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.
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 |
Appearance
- 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.
- The surface finish of the tubes, when especially specified shall be agreed upon by the purchaser and the manufacturer.
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.
Grade and Designation
The grade and designation of the tube shall be as given as follows table.
| Grade | Designation | |
|---|---|---|
| Grade 11 | A | STKM 11A |
| Grade 12 | A | STKM 12A |
| B | STKM 12B | |
| C | STKM 12C | |
| Grade 13 | A | STKM 13A |
| B | STKM 13B | |
| C | STKM 13C | |
| Grade 14 | A | STKM 14A |
| B | STKM 14B | |
| C | STKM 14C | |
| Grade 15 | A | STKM 15A |
| C | STKM 15C | |
| Grade 16 | A | STKM 16A |
| C | STKM 16C | |
| Grade 17 | A | STKM 17A |
| C | STKM 17C | |
| Grade 18 | A | STKM 18A |
| B | STKM 18B | |
| C | STKM 18C | |
| Grade 19 | A | STKM 19A |
| C | STKM 19C | |
| Grade 20 | A | STKM 20A |
The sub classification letter symbols A, B and C are used to indicate distinction of method of manufacturing the tube, cold working process, heat treatment, etc.
World standard Comparative with JIS G3445
| NUBER | GRADE | NUBER | GRADE | NUBER | GRADE | NUBER | GRADE | |
|---|---|---|---|---|---|---|---|---|
| D 3517 | Grade 11 A | STKM 11 A | A513 | MT1010 | G-3445 | STKM11A | – | – |
| A519 | MT1010 | |||||||
| Grade 12A | STKM 12 A | A513 | MT1015 | STKM12A | 980 | CDS-3 | ||
| A519 | MT1015 | |||||||
| Grade 12 B | STKM 12 B | – | – | STKM12B | – | – | ||
| Grade 12C | STKM 12C | A512 | MT1015 | STKM12C | – | – | ||
| A513 | ||||||||
| Grade 13 A | STKM 13 A | A512 | MT 1025 | STKM13A | – | – | ||
| A513 | MTX1025 | |||||||
| A519 | MT 1025 | |||||||
| Grade13B | STKM 13 B | – | – | STKM13B | 980 | CDS-4 | ||
| Grade13 C | STKM 13 C | – | – | STKM13C | – | – | ||
| Grade14 A | STKM 14 A | A513 | MT1030 | STKM14A | 1717 | CDS-103 | ||
| A519 | MT1030 | |||||||
| Grade14 B | STKM 14 B | – | – | STKM14B | – | – | ||
| Grade14 C | STKM 14 C | – | – | STKM14C | – | – | ||
| Grade15 A | STKM 15 A | A513 | MT1033 | STKM15A | 1717 | CDS-105 | ||
| Grade15 C | STKM 15 C | – | – | STKM15C | – | – | ||
| Grade16 A | STKM 16 A | A519 | MT1040 | STKM16A | 980 | CDS-5 | ||
| Grade16 C | STKM 16 C | – | – | STKM16C | – | – | ||
| Grade17 A | STKM 17 A | A519 | MT1050 | STKM17A | 980 | CDS-7 | ||
| 1717 | CDS-107 | |||||||
| Grade17 C | STKM 17 C | – | – | STKM17B | – | – | ||
| Grade18 A | STKM 18 A | A519 | MT1524 | STKM18A | 980 | CDS-9 | ||
| Grade18 B | STKM 18 B | – | – | STKM18B | – | – | ||
| Grade18 C | STKM 18 C | – | – | STKM18C | – | – | ||
| Grade19 A | STKM 19 A | – | – | – | – | – | ||
| Grade19 C | STKM 19 C | – | – | – | – | – | ||
| Grade20 A | STKM 20 A | – | – | – | – | – | ||
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.
Tolerance on Outside Diameter
| Division | Tolerances on outside diameter |
|---|---|
| No. 1 | Under 50mm ±0.5mm |
| 50mm or over ±1% | |
| No. 2 | Under 50mm ±0.25mm |
| 50mm or over ±0.5% | |
| No. 3 | Under 25mm ±0.12mm |
| 25mm or over to and excl. 40mm ±0.15mm | |
| 40mm or over to and excl. 50mm ±0.18mm | |
| 50mm or over to and excl. 60mm ±0.20mm | |
| 60mm or over to and excl. 70mm ±0.23mm | |
| 70mm or over to and excl. 80mm ±0.25mm | |
| 80mm or over to and excl. 90mm ±0.30mm | |
| 90mm or over to and excl.100mm ±0.40mm | |
| 100mm or over ±0.50% |
Tolerance of Thickness
| Division | Tolerances on wall thickness |
|---|---|
| No. 1 | Under 4mm |
| +0.6mm | |
| -0.5mm | |
| 4mm or over | |
| 15% | |
| -12.50% | |
| No. 2 | Under 3mm |
| ±0.3mm | |
| 3mm or over |
Protection and Packing:
Packed in wooden box or bundles protected with plastic paper, and suitably protected for sea-worthily delivery or as requested.
The tubes shall be delivered with a temporary corrosion protection. The type of protection shall be at the discretion of the manufacturer.
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