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About us
Tianjin lefin Industrial
TIANJIN LEFIN STEEL GROUP containing Tianjin lefin Industrial Co.,Ltd. 、Tianjin lefin steel import & export Co.,Ltd and Tianjin Shengqifeng International Trading Co., Ltd. -
Products
Steel Pipe Processing
Our main products include 1/2inch to 16 inch ERW PIPE/GI PIPE which has been produced according to BS1387/ASTM A53/EN10219/EN10255/EN10217 Standard -
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Service Capability
Guarantee Quality
Our steel pipes are suitable for oil, natural gas, shipbuilding, chemical industry, water conservancy, electrical, steel structure, construction and other related fields.
Our main products include 1/2inch to 16 inch ERW PIPE/GI PIPE which has been produced according to BS1387/ASTM A53/EN10219/EN10255/EN10217 Standard
Our main products include 1/2inch to 16 inch ERW PIPE/GI PIPE which has been produced according to BS1387/ASTM A53/EN10219/EN10255/EN10217 Standard
Has rich experience in steel pipe processing, can be customized according to customer requirements according to the drawing and sample processing, assist in the development of new products.
Kazakhstan JIS G3444 STK400 Carbon Steel Tubes
Product Description
Standard Overview
JIS G3444 STK 400 is a Japanese Industrial Standard (JIS) specification for carbon steel tubes used in mechanical and structural applications. Here is a detailed description of it:
● Standard Number: JIS G3444
Title: Carbon steel tubes for general structural purposes.
● Material Designation: STK 400
STK: Stands for "Structural Tubing, Carbon Steel."
400: Indicates the minimum tensile strength in MPa (Megapascals).
● Specification:
OD: 20MM - 660MM(ERW), 245MM - 1420MM(LSAW)
WT: 1.3MM - 16MM(ERW), 10MM - 50MM(LSAW)
Length: Commonly used 5.8M,6M,12M,or as your requirement.
Surface Treatments: Coating, Hot-dip galvanized, Painting
Application: Civil engineering, Architecture, Steel Towers, Scaffoldings, Struts, Piles for Suppression of Landslide, and other structures.
Chemical Composition (Typical Requirements)
The chemical composition of STK 400 steel tubes generally adheres to the following limits (may vary slightly by manufacturer):
● Carbon (C): Maximum 0.25%
● Silicon (Si): No specific limit
● Manganese (Mn): No specific limit
● Phosphorus (P): Maximum 0.040%
● Sulfur (S): Maximum 0.040%
Note: Exact composition may vary depending on manufacturing processes (e.g., seamless or welded tubes).
Mechanical Properties
Tensile Strength: Minimum 400 N/mm²
Yield Point of Proof Stress: Minimum 235 N/mm²
Elongation: Typically ≥ 20–25% (varies with tube dimensions and Manufacturing method).
Bendability: 90° bend angle with an inside radius of 6D (D is the outside diameter of the tube)
Flattening: Distance between plates (H) is 2/3D
Tensile Strength in Weld Zone: Minimum 400 N/mm²
Manufacturing Methods
Seamless: Marked as "S"
Electric Resistance Butt Welded: Marked as "B"
Automatic Arc Welded: Marked as "A"
Hot Finished: Marked as "H"
Cold Finished: Marked as "C"
As Electric Resistance Welded: Marked as "G"
Surface Finish: Usually plain (black) or galvanized for corrosion resistance (if specified).
Testing And Inspection
Chemical Analysis: To ensure the chemical composition meets the specified limits.
Mechanical Testing: Including tensile tests, flattening tests, and bending tests.
Non-Destructive Testing (NDT): To check for any internal defects.
Surface Inspection: To ensure there are no surface defects.
Dimensional Check: To verify that the dimensions of the pipes meet the required tolerances.
Applications
Structural Purposes: Suitable for general structural applications, civil engineering, construction, steel towers, scaffolding, pillars, piles for landslide suppression, and other structures.
Other Uses: It can also be used in various industries where low-pressure applications are required.
Conclusion
JIS G3444 STK 400 is a versatile carbon steel tube standard offering balanced strength, formability, and weldability for structural uses. Compliance with JIS ensures consistency in quality and performance for industrial applications in Japan and internationally.
Address: Hengtai Road,Daqiuzhuang Town,Jinghai County,Tianjin,China
Mob: +8615122229899(whatspp)
Phone: +86 22 58171905
Fax: +86 22 58171902
E-mail:info@lefinsteel.com
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