Steel with chromium content of more than 5% 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 gb3280 & mdash; 92 regulations, the thin-walled steel pipe is cold drawn technology, while the square pipe generally uses hot rolling technology. If it is distinguished by the unit of measurement, it is generally believed that the watershed between the square pipe and the thin-walled steel pipe is that the wall thickness diameter is equal to 0.02, and the thin-walled steel pipe is that the wall thickness diameter is less than 0.02, Larger than is the square pipe. In terms of use, thin-walled steel pipes are mostly used in pipes. The square tube is mostly used in the blank of hollow parts. Used on pressure bearing and important pipelines.
Baile atha I.The advantage of empty bending is that it can bend the side length when the real bending cannot be carried out, such as synchronous bending and finishing of the upper side and side of q355b square tube. Empty bend can also bend R & amp; amp; amp; lt; 0.2T without fracture of pipe wall.
Stainless steel q355b square pipe for mechanical structure, Standard No.: gbt12770-1991. Representative material 0Cr 1cr1 00cr19ni 1Cr18Ni 0cr18ni11nb, etc. It is mainly used for machinery, automobile, bicycle, furniture, hotel and restaurant decoration and other mechanical parts and structural parts.
.Empty bending is the bending moment formed in one direction between the outer roll and the outer wall of the tube blank to bend the strip. Empty bending will compress the bending line, the compression effect will lengthen the bending line longitudinally, and the metal at the bending will accumulate and thicken, which is the compression thickening effect of empty bending.
Ordinary carbon steel is divided into Q19 Q2 q23 SS400, 20# steel, 45# steel, etc.
It is a kind of cleaning for the surface of square pipe. Shot blasting is often used to clean the casting surface or strengthen the surface of square pipe.
In the process of square pipe, we will conduct a variety of tests on it to ensure that the square pipe can be better used in practice. In order to make better use of large-diameter steel pipe, we will continue to innovate. Let's introduce the main elements contained in the lower pipe. For the martensitic chromium square tube, the main elements affecting the are chromium, the main influencing elements are nickel, molybdenum, aluminum, cobalt, nitrogen and titanium.
The difference between square pipe and seamless steel pipe the main feature of seamless steel pipe is no welding joint and can withstand large pressure. The product can be very rough as cast or cold drawn parts.
Requirements for samples samples can be taken from metal pipes with qualified appearance. Generally, sawing is adopted.
recommend.Forging has many advantages in improving the plasticity of q355b square tube and improving the quality of steel because the cast state of forged metal can be broken when forging q355b square tube. Therefore, there are forging workshops in some q355b square tube factories.
The raw material for rolling square tube is round tube blank. For a long time, square tube, rectangular tube, seamless square tube, galvanized square tube and galvanized tube have complete products, and the blank with a growth of about 1m shall be brought to the furnace for heating. The billet is sent to the furnace for heating at a temperature of about 1200 degrees Celsius. The fuel is hydrogen or acetylene. The temperature in the furnace is the key problem. After the round tube billet is discharged from the furnace, it should be pierced through the pressure piercer. Generally, the more common piercer is the conical roll piercer. This piercer has high production efficiency good product quality, large perforation expansion and can wear a variety of steel grades.
Tensile test is to form seamless q355b into a sample, pull the sample to fracture on the tensile testing machine and then measure one or more mechanical properties. Usually, only tensile strength, yield strength, elongation after fracture and reduction of area are measured.
In the trend of the times, we will change with the changes of the times, so that the square tube can be used more widely. In our daily life, we will the use of the square tube, let's introduce the difference between carbon steel and square tube.
Packaging strategy.At present, square tubes also have many good properties, strong corrosion resistance and heat resistance and are widely used in many scientific and technological fields. Therefore, even so, wise people still do not stop studying the surface adhesion resistance of square tubes. Square tubes in the future will have better performance and make more important contributions to development.
Product description of square tube square tube is a light thin-walled steel tube with hollow square section, also known as steel cold-formed profile. It is a section steel with square section shape and size, which is made of Q235 hot-rolled or cold-rolled strip or coil as the base material, cold bending and high-frequency welding. In addition to wall thickness thickening, the corner size and edge flatness of hot-rolled special square pipe reach or even exceed the level of resistance welding cold-formed square pipe. Good comprehensive mechanical properties, weldability, cold and hot workability and corrosion resistance, sawing is adopted. The inner and outer walls of the pipe shall retain the original surface without any processing. Sample length L & asymp; D (D is the outer diameter of the pipe). When the outer diameter is large, the length l shall not exceed 100mm. When the outer diameter is less than 20mm, l = 20mm. When cutting the sample, the surface of the sample shall not be damaged and the performance of the metal shall not be changed due to heating or cold processing. The edge of the section shall be flattened. The flattening test is a test to check the deformation performance of the metal pipe (seamless square pipe and rectangular pipe) flattened to the specified size and show its defects. Relevant flattening tests shall be carried out in accordance with relevant provisions of test standards.
Baile atha I.After 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
The square tube will be tested in many aspects of its performance in the process. Each test is for the square tube to have a good performance in practical application. So what are the different properties of square tubes? Next, I'll introduce the characteristics of the lower tubes in terms of mechanical properties.
It is feasible to use the theory to calculate static structures, such as warehouses, houses and bridges, but it is not suitable for moving components such as wheels. At this time, people often use the plastic theory. The research of the plastic theory can be traced back to 1914. In 1975, the European Design Association formulated a plastic design code, which is mainly used for static load plane beams and frame structures subjected to bending stress The solution is as follows: for high-rise buildings, more detailed calculations are needed.