ALLLAND Boiler Steel Pipe Supply
Welcome to ALLLAND. We specialize in the production of structural steel tubes compliant with the JIS G3444 standard. Our products are widely used in construction projects, bridge structures, machinery manufacturing, and various steel structure projects. We offer a wide range of specifications, including round steel tubes (CHS), covering various sizes and strength grades to meet diverse engineering needs. With mature production technology, a stable quality management system, and extensive export experience, ALLLAND has provided high-quality steel tube solutions for numerous structural engineering projects worldwide and is committed to becoming a long-term, trusted partner for our customers.
Alllandsteel is a steel pipe manufacturer based in China with 25 years of experience.
The facility spans 22,000 square meters, represents a RMB 700 million investment, and operates four production lines (JCOE, ERW, SMLS, SSAW) alongside five coating lines.
With an annual production capacity of 250,000 tons, the factory covers specifications ranging from Ø406 to Ø1524 and holds multiple international certifications (API/ASTM/EN/ISO/JIS). Focused on steel pipes, creating value for you!
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JIS G3444 is a Japanese Industrial Standard specifying requirements for structural welded or seamless carbon steel pipes. The standard outlines the primary application areas, including civil engineering, construction, steel towers, scaffolding, bracing, landslide prevention piles, and other general structural supports. It specifies the manufacturing methods, chemical composition, mechanical properties, dimensional tolerances, and inspection requirements for these pipes, covering both seamless and welded steel pipes (such as ERW). Common steel grades in JIS G3444 include STK290, STK400, STK490, STK500, STK540, and others, which are detailed below.
O.D.:
21.7-1016.0mm
W.T.:
2.0-22mm
Length:
3-18m
Material:
Carbon structural steel
Grades:
STK290、STK400、STK490、STK500、 STK540
Tube End Processing:
Square Cut, Bevelling, Threading, Grooving , Shouldering
Corrosion Prevention:
Lacquer, Varnish, Oiling, Galvanizing、FBE, 2LPP, 3LPP, 2LPE, 3LPE
Process:
Welding, Bending, Hole Drilling, Punching, Swaging, Tapering, Flaring, Expanding
Allland is a professional steel pipe manufacturer offering pipe specifications that comply with major global standards. Our JIS G3444 steel pipes are 100% traceable, and we maintain strict control over every aspect—from manufacturing processes and pipe quality to surface treatment—to ensure you find the right steel pipes for your needs.
| 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 | ||||
| Classification | Tolerances | |
| Class 1 | Under 50 mm | ± 0.5 mm |
| 50 mm or over | ±1% | |
| Class 2 | Under 50mm | ± 0.25 mm |
| 50mm or Over | ± 0.5% | |
| Classification | Tolerances | |||
| Seamless steel tube | Other than seamless steel tube | |||
| Class 1 | Under 4 mm | + 0.6 mm | Under 4 mm | + 0.6 mm |
| – 0.5 mm | – 0.5 mm | |||
| 4 mm or over | 0.15 | 4 mm or over to and excl. 12 mm | 0.15 | |
| -0.125 | -0.125 | |||
| 12 mm or over | 0.15 | |||
| -1.5mm | ||||
| Class 2 | Under 3 mm | ± 0.3 mm | Under 3 mm | ± 0.3 mm |
| 3 mm or over | ± 10% | 3 mm or over to and excl. 12 mm | ± 10% | |
| 12 mm or over | 0.1 | |||
| – 1.2 mm | ||||
1. The tolerances on wall thickness of hot finished seamless steel tubes shall follow Class 1.
The tolerance on wall thickness of tubes exceeding 1016.0 mm in outside diameter may be agreed upon between the purchaser and the manufacturer.
(2) The tolerances on length of tubes shall, unless otherwise specified, be not less than the specified length.
Under this standard, steel pipe grades include: STK290, STK400, STK490, STK500, and STK540. The strength and chemical composition requirements vary to meet the needs of various structural components.
| Grade | C | Si | Mn | P | S |
| SKT290 | – | – | – | 0.050 max. | 0.050 max. |
| SKT400 | 0.25 max. | – | – | 0.040 max. | 0.040 max. |
| SKT500 | 0.24 max. | 0.35 max. | 0.30 to 1.30 | 0.040 max. | 0.040 max. |
| SKT490 | 0.18 max. | 0.55 max. | 1.50 max. | 0.040 max. | 0.040 max. |
| SKT540 | 0.23 max. | 0.55 max. | 1.50 max. | 0.040 max. | 0.040 max. |
| Grade | Tensile 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 | ||
| SKT290 | 290 min. | – | 290 min. | 2/3 D | 90° | 6 D |
| SKT400 | 400 min. | 235 min. | 400 min. | 2/3 D | 90° | 6 D |
| SKT490 | 490 min. | 315 min. | 490 min. | 7/8 D | 90° | 6 D |
| SKT500 | 500 min. | 355 min. | 500 min. | 7/8 D | 90° | 6 D |
| SKT540 | 540 min. | 390 min. | 540 min. | 7/8 D | 90° | 6 D |
| NOTE 1 In this table, D stands for the outside diameter of the tube. | ||||||
Chemical analysis: To ensure compliance with the chemical composition requirements for the corresponding grade
Tensile test: To ensure compliance with the mechanical property requirements for the corresponding grade
Bend test: To inspect the formability and weld quality of the steel pipe
Flattening test: To assess the steel pipe’s resistance to deformation and weld quality
The JIS G3444 standard requires that each inspected steel pipe be marked to ensure traceability.
The markings shall include:
(1) Applicable standard
(2) Steel grade
(3) Symbol denoting the method of manufacture
(4) Dimensions
(5) Manufacturer’s name or identifying brand
(6) Heat No. / Lot No.
This standard is primarily applied in the field of building structures, such as steel-framed buildings, work platforms in industrial facilities, and equipment supports. It is also used for light-gauge steel framing and structural columns in residential construction.
Due to their excellent cold-forming and weldability properties, STK 290 and STK 400 are suitable as base materials for cold-formed steel sections.
Steel pipes conforming to this standard are also widely used in infrastructure support and construction projects in the energy sector.
Power Transmission and Communication Towers: Typical applications for high-strength steel pipes such as STK 500 and STK 540. Used in the manufacture of angle steel or tubular steel towers for high-voltage power transmission lines, microwave communication towers, and broadcast transmission towers.
Bridge Engineering: Steel-concrete composite arch ribs for highway bridges, truss-type longitudinal girders, and the main structures of pedestrian overpasses.
Foundations and Substructures: Used as steel pipe piles.
STK 400 and STK 500 are most commonly used in construction scaffolding and support systems, as well as for temporary fencing and guardrails.
After hot-dip galvanizing, they are widely used in applications requiring high weather resistance, such as outdoor billboard poles, streetlight poles, highway guardrail posts, and solar photovoltaic mounting structures.
