Except for the thickening of wall thickness， the corner size and edge flatness of square pipe reach or even exceed that of resistance welding cold forming
8The cutting surface of the square tube shall be true circle， and the cutting line shall be at right angles to the axis of the square tube. Excessive force is the reason for cutting the square tube into flat or oval， so the square tube should be cut with appropriate force.
mThe floating mandrel mill is in its heyday
When cutting， please fix it with square tubes such as vise， and then cut it after it is fixed.
LTaschupThe welded joints of square pipes are subject to on-line continuous ultrasonic automatic flaw detector to ensure the NDT coverage of spiral welds. If there are defects，Rectangular Pipe it will automatically alarm and spray marks. The production will adjust the process parameters at any time to eliminate the defects in time.
HgDuring the storage of square tubes，Galvanized square pipe and rectangular pipeThe importance of the selection of machinery pay attention to the stacking layers of square tubes to avoid local stress at the tube end caused by too many layers resulting in radial plastic deformation and layer damage of square tubes. It is recommended that the stacking layers of smooth pipes refer to apirp l- Recommended Practice for railway transportation of square pipes for pipelines or apirp lw- Recommended Practice for ship and sea vessel transportation of square pipes for pipelines. It can also be determined by test or implemented according to the safe stacking height of square pipes. The stacking layers of pipes shall be implemented according to GBT - polyethylene layer of buried steel pipelines.
In & sigma; Expressed in%. The calculation formula is: where: L -- gauge length after sample breaking， mm; L -- original gauge length of sample， mm. Reduction of area (& psi;) in the tensile test， the percentage between the large reduction of the cross-sectional area at the reduced diameter and the original cross-sectional area after the specimen is broken is called the reduction of area. In & psi; Expressed in%. The calculation formula is as follows: where: S -- original cross-sectional area of the sample， mm; S -- small cross-sectional area at the reduced diameter after sample breaking， which is called square pipe.
wThe strength plasticity and angle discussed later are the machine function indicators of metal under static load. In practice， many mechanical machines are under repeated load， and the whole opportunity is tired in this environment.
FFor seamless qb square tubes， there is a certain hardness，Rectangular Pipe so there are still many for bearing in application， so it is necessary to test the mechanical properties of seamless qb square tubes.
RGood reputationWhen the square tube is covered， the surface of the square tube shall be ventilated to avoid the collection of water vapor on the surface due to difficult volatilization.
hMStainless steel qb square pipe for fluid transportation， Standard No.: gbt-. The representative materials are Cr crni crni cr crninb， crnimo etc.， which are mainly used to transport low-pressure corrosive media.
The square tube adopts the electric contact pressure gauge to press down the pressure of the oil cylinder on both sides of the conveyor to ensure the smooth transportation of the strip steel.
Use classification square tubes are divided into: square tubes for decoration， square tubes for machine tool equipment， square tubes for mechanical industry， square tubes for chemical industry， square tubes for steel structure，Rectangular Pipe square tubes for shipbuilding， square tubes for automobile，Galvanized square pipe and rectangular pipeThe importance of the selection of machinery square tubes for steel beams and columns， and square tubes for special purposes.
Equipment maintenancekAfter perforation， the round tube blank is successively rolled by cross rolling， continuous rolling or rolling. Take off the pipe after sizing. The conical drill bit of the sizing machine rotates into the steel embryo at high speed to form a steel pipe. The inner diameter of the steel pipe is determined by the outer diameter length of the sizing machine bit. After sizing， the steel pipe enters the cooling tower for water spray cooling. After cooling， the steel pipe will be straightened. After straightening， the steel pipe is sent to the gold pipe by belt
IAccording to metallographic classification， so in the subsequent application process，Galvanized pipe_ Galvanized square pipe_ Seamless steel pipe_ Square tube - Wuxi Jiahang the requirements for square tube in many places are also quite strict， especially for surface treatment. Today， we briefly introduce how the polishing process should be carried out.
lSteel with chromium content of more than % in steel and high corrosion of external medium (acid， alkali salt) is called square pipe. According to the condition in steel， square tubes can be divided into martensite， ferrite， austenite and ferrite & mdash; Austenite type， precipitation hardening square tube， according to the standard gb & mdash; regulations， a total of regulations.
dMStainless steel qb square pipe for mechanical structure， Standard No.: gbt-. Representative materials Cr cr crni CrNi crninb， etc. are mainly used for mechanical parts and structural parts such as machinery， automobile， bicycle， furniture， hotel and restaurant decoration.
igma; Su): large stress before the yield stress of the sample decreases; Lower yield point (& sigma; SL): the small stress in the yield stage when the initial instantaneous effect is not considered. The calculation formula of yield point is as follows: where: FS -- yield force (constant) in the tensile process of the sample， mm. Elongation after fracture (& sigma;) in the tensile test， the percentage of the length increased by the gauge length of the sample after breaking to the original gauge length is called elongation.