JIS G3444 steel Pipe
The Japanese Industrial Standard JIS G3444 is a standard for carbon steel tubes used for general structural and low pressure applications such as engineering, construction, piling, building and other general purpose applications. These pipes are available in many strength grades, each with different yield and tensile strengths. The standard covers grades such as STK290, STK400, and STK490, with the number indicating the minimum tensile strength in megapascals (MPa). For example, STK490 has a minimum tensile strength of 490 MPa.
JIS G3444 standard pipes are subject to strict quality control measures. This ensures they meet specific mechanical and chemical requirements such as tensile strength, yield strength, elongation and impact resistance. Gnee Steel Pipe regularly conducts tests to ensure compliance with standards, guaranteeing that the pipes will perform as expected in structural and industrial applications.
Gnee Steel Pipe supplies JIS G3444 pipes in various sizes. Our high-quality pipes have been successfully exported to more than 700 companies in more than 60 countries. Contact us for steel pipe prices and stock.
General Parameters Of JIS G3444 Carbon Tube
| Product | JIS G3444 Carbon Steel Pipe For General Structural Purposes |
| Length | 5-12m or as customer required |
| Origin | China |
| Monthly Output | 20 million-30 million pieces per month |
| Applications | Civil engineering: Bridges, tunnels, and other large infrastructure projects. Construction: Building frameworks, scaffolding, and structural supports. Automotive: Components for trucks, trailers, and other vehicles. |
| Surface | Bare,black painted,varnished,oiled, 2PE, 3PE |
| Delivery state | Hot Rolled, Cold Drawn |
| Steel Grade | STK 290/ STK 400/ STK 490/ STK 500/ STK 540 |
| Supplementary Technology | Plain or threaded with socket, beveled with plastic caps, hydraulic testing, eddy current, Infrared test. |
JIS G3444 Steel Pipe Classification And Symbols
JIS G3444 tubes are classified into five grades, and the grade symbols and manufacturing methods are as follows.
| Symbol of Grade | Symbol of Manufacturing Method | ||
|---|---|---|---|
| Tube Manufacturing Method | Finishing Method | Marking | |
| STK 290 | Seamless: S Electric resistance welding: E Butt welded: B Automatic arc welded: A | Hot finished: H Cold finished: C As electric resistance welded: G | Hot finished seamless steel tube: -S-H Cold finished seamless steel tube: -S-C As electric resistance welded steel tube: -E-G Hot finished ERW steel tube: -E-H Cold finished ERW steel tube: -E-C Butt welded steel tube: -B Automatic arc welded steel tube: -A |
| STK 400 | |||
| STK 490 | |||
| STK 500 | |||
| STK 540 | |||
| 1. Dimensions shall be marked by outside diameter and wall thickness. 2. Manufacturer’s name or its identifying brand 3. Symbol indicating the type of coating (in the case of using coated steel sheet or coated steel strip). This abbreviation for this symbol shall be as agreed between the purchaser and the manufacturer. | |||
More information About Steel Material JIS G3444
Tubes must be tested in accordance with the standards and the thermal analysis results must comply with the table below. When product analysis is requested by the customer, the tubing must be tested according to the standard and the product analysis values obtained must comply with the criteria in the table and be within the tolerances specified in table JIS G 0321.
| Symbol of Grade | C | Si | Mn | P | S |
|---|---|---|---|---|---|
| JIS G3444 STK 290 | – | – | – | 0.050max. | 0.050max. |
| JIS G3444 STK 400 | 0.25max. | – | – | 0.040max. | 0.040max. |
| JIS G3444 STK 490 | 0.18max. | 0.55max. | 1.65max. | 0.035max. | 0.035max. |
| JIS G3444 STK 500 | 0.24max. | 0.35max. | 0.30 to 1.30 | 0.040max. | 0.040max. |
| JIS G3444 STK 540 | 0.23max. | 0.55max. | 1.50max. | 0.040max. | 0.040max. |
| Notes: 1. If necessary, other alloy elements than those given in this table may be added. 2. For STK540, the chemical composition of tubes of wall thickness over 12.5 mm may be agreed upon between the purchaser and the manufacturer. | |||||
- Tensile Strength and Yield Point or Yield Stress: To ensure the quality of the tubes, they must be manufactured from high quality steel plates or strips. These materials must then be tested to confirm their tensile strength, yield point and yield stress. The tensile strength of the weld zone is also an important factor and must also be confirmed. However, if the buyer agrees, the weld zone tensile strength test can be omitted. All of these factors are important to ensure that the pipe is of the highest quality and can withstand any pressure or weight applied to it.
- Flattening: The flattening test is a method of detecting the presence of defects or cracks in seamless, resistance-welded or butt-welded steel pipe. The test involves placing the steel pipe between two plates and applying pressure to the top plate. The distance between the plates is controlled to ensure that the test is accurate. The flattening test is an important part of quality control for steel pipe and helps to ensure that the pipe is free of defects.
- Bendability: Tubes with an outside diameter of 50 mm or less may be specified for their bendability rather than their flattening capacity. Other tubes must be tested for bendability in accordance with the standard and the specimens must be free from imperfections or cracks. The table above specifies acceptable bend angles and inside bend radii. This ensures that the tube meets the necessary safety standards and can withstand the specified pressure.
| Symbol of Grade | Tensile Strength N/mm2 | Yield Point or Proof Stress N/mm2 | Weld Tensile N/mm2 | Flattening Resistance Strength | Bendability | |
|---|---|---|---|---|---|---|
| Distance between Flat Plates (H) | Bending Angle, a) | Inside Radius | ||||
| Applicable Outside Diameter | ||||||
| All Outside Diameters | All Outside Diameters | All Outside Diameters | All Outside Diameters | 50 mm or under | ||
| JIS G3444 STK 290 | 290 min. | – | 290 min. | 2/3D | 90° | 6D |
| JIS G3444 STK 400 | 400 min. | 235 min. | 400 min. | 2/3D | 90° | 6D |
| JIS G3444 STK 490 | 490 min. | 315 min. | 490 min. | 7/8D | 90° | 6D |
| JIS G3444 STK 500 | 500 min. | 355 min. | 500 min. | 7/8D | 90° | 6D |
| JIS G3444 STK 540 | 540 min. | 390 min. | 540 min. | 7/8D | 90° | 6D |
| NOTE 1 In this table, D stands for the outside diameter of the tube. NOTE 2 1 N/mm 2 = 1 MPa Note a) The bending angle shall be measured from the starting point of the bend. | ||||||
Dimensional tolerances of JIS G3444
| Classification | Outside Diameter b) | Tolerances on | Applicable Division |
|---|---|---|---|
| Outside Diameter c) | |||
| Class 1 | Under 50mm | ± 0.5mm | Applied when there is no specification. Applicable to hot-finished seamless steel tubes. |
| 50mm or Over | ± 1% | ||
| Class 2 | Under 50mm | ± 0.25mm | Applied when there is a specification. Not applicable to hot-finished seamless steel tubes. |
| 50mm or Over | ± 0.5% | ||
| Notes | a) For the local parts such as repaired parts if the wall thickness can be confirmed to be within the tolerance in the table below, the outside diameter tolerance of this table need not be applied. | ||
| b) The method for measuring the outside diameter of tubes exceeding 350mm in outside diameter may be determined by the circumferential length. The mutual conversion of outside diameter D and the circumferential length l shall be by the following formula: D = l / π Where D: outside diameter (mm) l: circumferential length (mm) π：3.1416 | |||
| c) The tolerances on the outside diameter of ends of electric resistance welded and automatic arc welded steel tubes exceeding 350mm in outside diameter shall be ±0.5%。 | |||
| Classification | For Seamless Steel Tube | For Other than Seamless Steel Tube | Applicable Division | ||
|---|---|---|---|---|---|
| Wall Thickness | Tolerance of Wall Thickness | Wall Thickness | Tolerance of Wall Thickness | ||
| Class 1 | Under 4mm | +0.6mm, -0.5mm | Under 4mm | +0.6mm, -0.5mm | Applied when there is no specification. Applicable to hot-finished seamless steel tubes. |
| 4mm or Over | +15%, -12.5% | 4mm or Over to and excl. 12mm | +15%, -12.5% | ||
| 12mm or Over | +15%, -1.5mm | ||||
| Class 2 | Under 3mm | ±0.3mm | Under 3mm | ± 0.3mm | Applied when there is a specification. Not applicable to hot-finished seamless steel tubes. |
| 3mm or Over | ±10% | 3mm or Over to and excl. 12mm | ±10% | ||
| 12mm or Over | +10%，-1.2mm | ||||
| Notes | a) The tolerances on the wall thickness of tubes exceeding 1016.0 mm in outside diameter may be agreed upon between the manufacturer and the purchaser. | ||||
Features & Advantages of JIS G3444 Steel Structural Pipe
Gnee has been providing high quality JIS G3444 steel pipes with a variety of excellent properties to customers around the world for 15 years. JIS G3444 steel pipes offer a range of advantages, including high strength, good weldability, versatility, and cost-effectiveness. Their suitability for a variety of structural and industrial applications, coupled with their excellent mechanical properties and ease of fabrication, makes them an essential choice for projects that demand reliable and durable steel components.
Corrosion Resistance
While JIS G3444 steel pipes are not as corrosion-resistant as stainless steel, they can be coated or galvanized to improve their resistance to rust and corrosion. With appropriate protective treatments, these pipes can be used in outdoor or harsh environments without significant risk of degradation.
Good Resistance to Deformation
The mechanical properties of JIS G3444 steel pipes provide excellent resistance to deformation, which is particularly important in applications that involve high loads, vibrations, or pressure changes. This resistance ensures that the pipes maintain their shape and structural integrity even under challenging conditions.
High Toughness
The toughness of JIS G3444 steel pipes allows them to absorb energy and resist fractures, even in low-temperature environments. This characteristic is critical for applications where structural components may be exposed to dynamic loads or impacts, such as in earthquake-prone areas or heavy machinery installations.
Cost-Effective Material
Compared to other structural materials, carbon steel is relatively inexpensive, and JIS G3444 steel pipes offer a cost-effective solution for many construction and industrial projects. This cost advantage makes them attractive for large-scale projects that require a significant quantity of structural steel components without breaking the budget.
Good Formability and Weldability
JIS G3444 steel pipes are known for their excellent formability, allowing them to be easily shaped, bent, or fabricated into various structures without compromising their strength. The carbon steel used in these pipes is also highly weldable, making them easy to join or integrate with other steel components in construction projects. This weldability is essential for industries that rely on complex frameworks or structural assemblies.
High Tensile Strength
One of the primary advantages of JIS G3444 steel pipes is their high tensile strength, which ensures they can withstand significant stress without breaking or deforming. This makes them suitable for structural applications that require pipes to support heavy loads or resist external forces, such as scaffolding, bridges, and industrial frameworks. Their durability also contributes to a longer service life in harsh environments.
What Can Gnee Guarantee For Our Customers?
Quality Assurance
As a supplier with 15 years of experience, we promise to provide high quality steel pipes, which comply with international standards and industry specifications, such as ISO, ASTM, EN, or JIS, etc. Gnee can provide relevant quality certifications, test reports & material certifications.
Faster Delivery Time
Gnee has a large inventory of steel pipes and multiple production lines. We respond to customers’ orders on time and provide customers with reasonable transportation and delivery solutions. We promise to deliver steel pipes according to the time specified in the contract.
Comprehensive Services
Gnee provides comprehensive services for customers. Services include steel pipe customization, technical support & consultation, sample provision, etc. Through the guidance of a professional team, customers can ultimately purchase steel pipe specifications, sizes, and materials that meet project requirements.
Competitive Price
As a supplier, Gnee can promise to provide competitive prices and conduct reasonable negotiations with customers. Gnee has its own factory and production lines. Also, we have established stable cooperative relationships with many reliable raw material suppliers and can provide high-quality steel pipes to the world at factory prices.
Inventory And Delivery Of Steel Pipe
Gnee factory has a large inventory of steel pipes and supports bulk orders. We also offer a variety of logistics solutions. Come and contact us.
Why Choose Gnee As A Steel Pipe Distributor?
In addition, our tubes have been successfully exported to more than 60 countries such as Vietnam, Malaysia, Indonesia, Pakistan, UAE, and South Korea, etc. Many regular customers visit our company and factory and make multiple orders.
What Services Does Gnee Provide?
Gnee can provide the following measurement services for pipe:
1. Dimensional measurement: Measure the dimensional parameters such as length, width, and thickness by measuring instruments to ensure the pipe is qualified and meets the design requirements.
2. Surface measurement: Measure parameters such as flatness, unevenness, and surface roughness of pipe surface to help ensure that the quality and surface state of the pipe meet the requirements.
3. Thickness measurement: Use a thickness measuring instrument to accurately measure the thickness of the pipe to ensure that it meets the design requirements.
4. Material measurement: Use material analysis instruments to measure the chemical composition and mechanical properties of the product to ensure that the quality and performance meet the requirements.
5. Bending and Deformation Measurements: The degree of bending and deformation of the steel pipe is measured and monitored by using tools such as bending measuring instruments and displacement sensors to ensure that it is within the allowable range.
Gnee can customize the size and shape of steel pipes for your project according to specific project needs. The custom design of the pipe is carried out by a professional engineer and design team. Based on the requirements and constraints of the project, they will use calculation and simulation tools, combined with experience and technical knowledge, to optimize the steel pipe design to meet the specific needs of your engineering.
● According to the strength requirements of structural design, adjust the thickness, width, and length of pipes.
● The shape of the steel pipe can be designed according to the characteristics of the project.
● If you consider the convenience of installation and maintenance, we can also add openings and passages for easy access and operation in the design for areas that require frequent maintenance.
Purchasing Gnee steel pipe can provide the following deep processing services. We can customize according to the specific needs of customers to meet the requirements.
Cutting service: Pipe can be custom cut to obtain the desired shape and size according to the needs of customers. For example, flame cutting, plasma cutting, laser cutting, etc., can cut steel pipes into required blocks, special-shaped parts.
Bending and forming: Pipes are bent and formed by stress application and appropriate processes to obtain the desired shape.
Welding service: Pipe can be subjected to various types of welding services, including manual arc welding, gas-shielded welding, laser welding, etc.
Turning and machining of holes: Turning and machining of holes in pipes by using machining equipment. These processes produce smooth surfaces, precise holes and threads to meet specific assembly requirements.
Surface treatment: In order to improve the corrosion resistance and aesthetics of the steel pipe, surface treatment can be carried out. This includes methods such as spraying, hot-dip galvanizing, electroplating, etc. to add a protective layer and provide corrosion resistance.
Gnee can provide the following testing services through third-party testing agencies. These third-party testing services can provide independent, objective verification that pipes comply with relevant standards and regulations.
Material chemical composition analysis: Through chemical composition analysis, determine whether the composition of the steel pipe meets the standard requirements.
Mechanical performance test: Mechanical performance test includes tensile test, impact test, bending test, etc., which are used to determine whether the mechanical properties such as strength, toughness and ductility of products meet the specified requirements.
Metallographic testing: Through metallographic testing, check the structure, grain size, non-metallic inclusions, etc. of pipes to evaluate their quality and performance.
Corrosion performance test: Through the corrosion performance test, evaluate the corrosion resistance of pipes, including salt spray corrosion resistance, chemical corrosion resistance, etc.
Hardness test: Hardness test is used to measure the hardness of pipe, and its strength and wear resistance can be evaluated according to the hardness value.
Ultrasonic flaw detection: Ultrasonic flaw detection is used to detect internal defects of pipes, such as cracks, pores, inclusions, etc.
