Steel and Structural Pipes

Grid structure is composed of similar grids or small dimension units. This structural pipe is often used in roof structure. Our company is able to provide high-quality seamless steel tube for lattice framed structure service. This product is applicable to large, medium or small span roof systems. JST structural pipes are extensively used in stadium, club, exhibition hall, theater, station waiting hall, airport, warehouse, workshop and other public buildings. This seamless steel tube can also be applied in various forms of special structures with different functions to make buildings more solid and beautiful.

• This structural pipe can make the lattice framed structure have big space stiffness, integrity and strong earthquake-resist capacity. It can also withstand the negative influence of uneven settlement of foundation.
• JST seamless steel tube used for grid structure is of light weight and uses less steel.
• It is also applicable to kinds of architecture in planar form, such as rectangular, round, circular sector or polygon shape.
• We often use Q235 or Q345 steel to produce structural pipes. We even adopt small specifications of rod piece section to construct big span buildings. Grid structure can make full use of the strength of seamless steel tubes and save steel.
• Lattice framed structure and its rod pieces have uniform specifications, so the pipes are suitable for industrialized production. This provides favorable conditions and guarantee for improving the engineering progress.

• The manufacturing of grid structured seamless steel tubes must be in accordance with the requirements of GB50205-2001 Steel Structure Construction and Inspection Rules.
• Steel plate should be welded in full penetration. When δ is equal to or more than 8 mm, we do ultrasonic inspection and checkout for the welding seam. The inspection ratio is 20 percent of the length of welding seam. If structural pipe complies with GB11345-89B III class inspection standard, it is qualified. (δ refers to the thickness of steel plate.)
• JST often uses Q345 and Q235 grades of seamless steel tubes to produce lattice framed structures. Chemical composition and mechanical property should respectively comply with GB/T1591-94 low alloy and high strength structural steel and GB700-88 carbon structural steel.
• Our structural pipes are manufactured from high-quality steel. Before entering warehouse, inspectors will check the quality certificate and check each indicator. When they ensure that seamless steel tubes are qualified in accordance with relevant standards, the products can be put in storage.

Mechanical and Processing Properties Parameters

Note:

• When do drawing and bending test, we should select transverse steel test sample. The steel with the width of less than 600 mm, we choose longitudinal test piece.
• The elongation of seamless steel tube is allowed to be reduced by ±1% than the values in the above table.
• The elongation of Q345 grade steel plate with the thickness of 35 mm can be reduced by ±1%.
• For the round or square steel with the side length or diameter more than 50 mm to 100 mm, the elongation can be reduced by ±1% than the values in the above table.
• The upper limit value of tensile strength of wide steel strips will not be treated as the delivery condition.
• Grade A steel must be done with bending test. For other grades of steel, if suppliers can guarantee the bending test result complies with the requirements in the above table, the test can be avoided.
• The impact force and test temperature in Charpy (V-notch) impact test should comply with the requirements on the table. Impact force value is calculated by the arithmetic mean value of three samples in a group. It allows one sample value to be below the specified value in the table, but not less than 70% of the specified value.
• When we adopt small size samples to do impact test (5 mm × 10 mm × 55 mm), the test result should not be less than 50% of the specified value.
• Q460 and various grades of D and E steel generally do not supply profile steel and steel bar.

Jiangyin Changjiang Steel Tube Making Factory is a leading supplier and exporter of structural pipes in China. Our company is a large scale enterprise possessing the production capacity of 600,000 tons of special seamless steel pipes. Our seamless steel tubes mainly include fluid pipe, high pressure boiler pipe, API pipe, marine pipe, alloy pipe, tubing, casing, line pipe, etc. With advanced technological equipment, tremendous technical strength and reliable product quality, our structural pipes have been exported to the Middle East, CIS, Southeast Asia, Africa, South America, North America, Europe, Australia and many other countries and regions.

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