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Q345B Square Pipe

Q345B square tube, 16Mn square tube, Q345B square tube, square tube, rectangular tube, seamless square tube, stainless steel square tube, square rectangular tube, q345b square tube, large diameter thick-walled square tube, Q345C square tube, stainless steel square Rectangular steel pipes, seamless square rectangular steel pipes and other square pipe products, We manufacture Square Hollows over 10 years, with good reputation. We exported 1000-5000tons to Africa,UAE,Pakistan,ect…every year. Welcome to visit us, pls send your inquire if necessary.

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Q345B square tube is produced in accordance with the national standard GBT 6728-2002 cold-formed hollow section steel for the size, shape, weight and allowable deviation of the structure. It is made of Q345B strip steel after processing. The Q345B square tube is made of Q345B material (low alloy), which is very different from the ordinary square tube in the raw material material (Q195, Q215, Q235). Generally, Q345B strip steel (low alloy) is unpacked , Flattened, crimped, welded to form a round tube, and then rolled into a square tube from the round tube and then cut into the required length. The usual length is 6 meters, and the large amount of 12 meters can be processed according to customer requirements. Generally, the small size is 50 pieces per pack, and the large size is 4 pieces each and the weight is controlled at about 3 tons. Q345B square tubes are mostly 80MM*80MM-500MM*500MM in large specifications in stock, and the thickness is 3MM-16MM.

Q345B square tube is a hollow square section light thin-walled steel tube, also known as steel refrigerated bending section. It is a section steel with a square cross-section shape and size made of Q345B hot-rolled or cold-rolled strip or coil as the base material, which is formed by cold bending and then welded by high-frequency welding. In addition to the thickening of the wall thickness of the hot-rolled extra-thick wall square pipe, the corner size and edge flatness of the hot-rolled extra-thick-walled square pipe reach or exceed the level of the resistance welded cold-formed square pipe.

Q345B square tube use
Q345B square tubes are generally used in construction, machinery manufacturing, steel construction projects, shipbuilding, solar power generation brackets, steel structure engineering, power engineering, power plants, agricultural and chemical machinery, glass curtain walls, automobile chassis, airports, etc.
Q345B square tube seamless and welded
Q345B seamless square tube is formed by extruding Q345B seamless round tube.
Q345B square tube plasticity
Plasticity refers to the ability of metal materials to produce plastic deformation (permanent deformation) without damage under load.
Q345B square tube hardness
Hardness is a measure of the hardness of metal materials. The most commonly used method for measuring hardness in production is the indentation hardness method, which uses an indenter of a certain geometric shape to press into the surface of the metal material to be tested under a certain load, and the hardness value is determined according to the degree of indentation.
Commonly used methods include Brinell hardness (HB), Rockwell hardness (HRA, HRB, HRC) and Vickers hardness (HV).

Q345B square tube strength
Strength refers to the resistance of metal materials to damage (excessive plastic deformation or fracture) under static load. Since the load acts in the form of tension, compression, bending, shearing, etc., the strength is also divided into tensile strength, compressive strength, bending strength, and shear strength. There is often a certain relationship between various strengths, and tensile strength is generally used as the most basic strength indicator in use.

Q345B square tube branch weight calculation formula: 4 sides added * thickness * 0.00785 * length
Q345B rectangular pipe support weight calculation formula: (side length + side length) * 2 * 0.00785 * wall thickness * length

Q345B Square Pipe Specification list:

Product Size mm Produce Size mm
Q345B SQUARE PIPE 50*50*2.5 Q345B SQUARE PIPE 300*200*14
Q345B SQUARE PIPE 80*80*4-8 Q345B SQUARE PIPE 300*200*16
Q345B SQUARE PIPE 100*100*4-12 Q345B SQUARE PIPE 350*350*8
Q345B SQUARE PIPE 120*120*4-12 Q345B SQUARE PIPE 350*350*10
Q345B SQUARE PIPE 140*140*5-12 Q345B SQUARE PIPE 350*350*12
Q345B SQUARE PIPE 150*150*5-12 Q345B SQUARE PIPE 350*350*14
Q345B SQUARE PIPE 160*160*5-12 Q345B SQUARE PIPE 350*350*16
Q345B SQUARE PIPE 180*180*5-12 Q345B SQUARE PIPE 400*200*8
Q345B SQUARE PIPE 200*200*5-16 Q345B SQUARE PIPE 400*200*10
Q345B SQUARE PIPE 250*250*5-16 Q345B SQUARE PIPE 400*200*12
Q345B SQUARE PIPE 280*280*6-16 Q345B SQUARE PIPE 400*200*16
Q345B SQUARE PIPE 300*300*6-16 Q345B SQUARE PIPE 400*300*8
Q345B SQUARE PIPE 300*150*8 Q345B SQUARE PIPE 400*300*10
Q345B SQUARE PIPE 300*150*10 Q345B SQUARE PIPE 400*300*12
Q345B SQUARE PIPE 300*150*12 Q345B SQUARE PIPE 400*300*14
Q345B SQUARE PIPE 300*200*6 Q345B SQUARE PIPE 400*400*8
Q345B SQUARE PIPE 300*200*8 Q345B SQUARE PIPE 400*400*10
Q345B SQUARE PIPE 300*200*10 Q345B SQUARE PIPE 400*400*12
Q345B SQUARE PIPE 300*200*12 Q345B SQUARE PIPE 400*400*16

Mechanical character & Chemical element of normal material:

Q195 C Mn Si S P
0.06-0.12 0.25-0.50 ≤0.30 ≤0.050 ≤0.045
Tensile strength: 315-430(Mpa)
Yield strength:195(Mpa)
Q235 C Mn Si S P
0.12-2.0 0.3-0.70 ≤0.30 ≤0.045 ≤0.045
Tensile strength: 375-460(Mpa)
Yield strength:235(Mpa)
Q345 C Mn Si S P V
≤0.20 ≤1.70 ≤0.55 ≤0.040 ≤0.040 0.02-0.15
Tensile strength: 470-630(Mpa)
Yield strength:345(Mpa)

Rectangular and square hollow section

Chinese standard:GB/T 6728-2002 Grade:Q195,Q235 A,Q235B, Q345A,Q345B,Q345C,
American standard:ASTM A500 and so on Grade:Gr A Gr B Gr C GR D
Australia standard:AS1163 Grade:C250,C350,C450,
European:EN10219 and so on Grade:S235JR S235J2 S235J0 S275JR S275J2 S275JO S355JR S355J2 S355J0 S355K2
Japanese :JIS-G3466 and so on Grade:STKR400 STKR490 STKR500
India:IS4923-1997 Grade:YST210,240 and 310
Thailand:TIS:107-2533 Grade:H41 H50 HS51


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