JIS G 3444 also known as Black Steel Pipe, specifies the requirements for carbon steel pipes used for general structural and low pressure applications, making it an excellent choice for engineering, architecture, construction, etc.
The main grades covered are STK400 and STK490, which are low carbon steel grades. Other grades such as STK290, STK 540, and STK500, are also included.
Get A Free Quote| Production Standard | JIS G3444 |
|---|---|
| Manufacturing Processes | ERW (Electric Resistance Welding) |
| SSAW (Spirally Submerged Arc Welding) | |
| LSAW (Longitudinal Submerged Arc Welding) | |
| SMLS (Hot Finished / Cold Drawn Seamless) | |
| Outside Diameter | 21.7-1016.0mm |
| Wall Thickness | 2.0-22mm |
| Pipe Length | 3-18m |
| Steel Grade | STK290, STK 500, STK 400, STK 540, STK 490 |
| Corrosion Prevention | Lacquer, Varnish, Oiling, Galvanizing |
| FBE, 2LPP, 3LPP, 2LPE, 3LPE | |
| End Processes | Square Cut, Bevelling, Threading, Grooving , Shouldering |
| Further Processing | Welding, Bending, Hole Drilling, Punching, Swaging, Tapering, Flaring, Expanding |
|
Outside Diameter mm |
Wall Thickness mm | ||||||||
| 21.7 | 2 | – | – | – | – | – | – | – | – |
| 27.2 | 2 | 2.3 | – | – | – | – | – | – | – |
| 34 | 2.3 | – | – | – | – | – | – | – | – |
| 42.7 | 2.3 | 2.5 | – | – | – | – | – | – | – |
| 48.6 | 2.3 | 2.5 | 2.8 | 3.2 | – | – | – | – | – |
| 60.5 | 2.3 | 3.2 | 4 | – | – | – | – | – | – |
| 76.3 | 2.8 | 3.2 | 4 | – | – | – | – | – | – |
| 89.1 | 2.8 | 3.2 | – | – | – | – | – | – | – |
| 101.6 | 3.2 | 4 | 5 | – | – | – | – | – | – |
| 114.3 | 3.2 | 3.5 | 4.5 | – | – | – | – | – | – |
| 139.8 | 3.6 | 4 | 4.5 | 6 | – | – | – | – | – |
| 165.2 | 4.5 | 5 | 6 | 7.1 | – | – | – | – | – |
| 190.7 | 4.5 | 5.3 | 6 | 7 | 8.2 | – | – | – | – |
| 216.3 | 4.5 | 5.8 | 6 | 7 | 8 | 8.2 | – | – | – |
| 267.4 | 6 | 6.6 | 7 | 8 | 9 | 9.3 | – | – | – |
| 318.5 | 6 | 6.9 | 8 | 9 | 10.3 | – | – | – | – |
| 355.6 | 6.4 | 7.9 | 9 | 9.5 | 12 | 12.7 | – | – | – |
| 406.4 | 7.9 | 9 | 9.5 | 12 | 12.7 | 16 | 19 | – | – |
| 457.2 | 9 | 9.5 | 12 | 12.7 | 16 | 19 | – | – | – |
| 500 | 9 | 12 | 14 | – | – | – | – | – | – |
| 508 | 7.9 | 9 | 9.5 | 12 | 12.7 | 14 | 16 | 19 | 22 |
| 558.8 | 9 | 12 | 16 | 19 | 22 | – | – | – | – |
| 600 | 9 | 12 | 14 | 16 | – | – | – | – | – |
| 609.6 | 9 | 9.5 | 12 | 12.7 | 14 | 16 | 19 | 22 | – |
| 700 | 9 | 12 | 14 | 16 | – | – | – | – | – |
| 711.2 | 9 | 12 | 14 | 16 | 19 | 22 | – | – | – |
| 812.8 | 9 | 12 | 14 | 16 | 19 | 22 | – | – | – |
| 914.4 | 12 | 14 | 16 | 19 | 22 | – | – | – | – |
| 1016 | 12 | 14 | 16 | 19 | 22 | – | – | – | – |
JIS G 3444 steel pipe consists of a balanced mixture of carbon, manganese, phosphorus, sulfur and silicon. The carbon content gives the pipe its strength and hardness, while manganese enhances its toughness. Phosphorus and sulfur are kept to a minimum to prevent brittleness, and silicon is added to improve its heat resistance.
| Symbol of Grade | C | Si | Mn | P | S |
|---|---|---|---|---|---|
| STK290 | – | – | – | 0.050 max. | 0.050 max. |
| STK400 | 0.25 max. | – | – | 0.040 max. | 0.040 max. |
| STK490 | 0.18 max. | 0.55 max. | 1.65 max. | 0.035 max. | 0.035 max. |
| STK500 | 0.24 max. | 0.35 max. | 0.30 to 1.30 | 0.040 max. | 0.040 max. |
| STK540 | 0.23 max. | 0.55 max. | 1.50 max. | 0.040 max. | 0.040 max. |
| Symbol of Grade | Tensile Strength Strength N/mm2 | Yield Point or Proof Stress N/mm2 | Weld Tensile Strength N/mm2 | Flattening Resistance | Bendability | |
| Distance Between Flat Plates（H） | Bending Angle | Inside Radius | ||||
| Applicable Outside Diameter | ||||||
| All Outside Diameters | All Outside Diameters | All Outside Diameters | All Outside Diameters | 50 mm or under | ||
| STK290 | 290 min. | – | 290 min. | 2/3 D | 90° | 6 D |
| STK400 | 400 min. | 235 min. | 400 min. | 2/3 D | 90° | 6 D |
| STK490 | 490 min. | 315 min. | 490 min. | 7/8 D | 90° | 6 D |
| STK500 | 500 min. | 355 min. | 500 min. | 7/8 D | 90° | 6 D |
| STK540 | 540 min. | 390 min. | 540 min. | 7/8 D | 90° | 6 D |
| NOTE 1 In this table，D stands for the outside diameter of tube. | ||||||
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