and the tensile effect will shorten the longitudinal length of the bending line; The metal at the real bend will become thinner due to stretching.
After chemical treatment and surface treatment of the square tube, the appearance and quality of the square tube have been improved to another height, making the current square tube present in the market in a good state.
Aurora.According to metallographic classification, the annealed state of square tube: A. hypoeutectoid steel (ferrite + pearlite); b. Eutectoid steel (pearlite); c. Steel precipitation through a common square tube (pearlite + cementite); d. Ledeburite steel (pearlite + cementite).
Large diameter welded square pipe for low pressure fluid transmission, Standard No.: gbt14980-1994. Representative material: grade q235ab. It is mainly used to transport low-pressure fluids such as water, sewage, gas, air and heating steam.
.To change the required line shape of q355b square tube, it is necessary to forge the impact force of q355b square tube hammer or the pressure of hydraulic press and can also enhance the malleability of q355b square tube, that is, the performance of changing the shape without cracks.
Performance index analysis of square tube - plasticity refers to the ability of metal materials to produce plastic deformation without deformation under load.
Now, Fangguan can achieve such good results in the market, which is completely inseparable from the manufacturers' hard work in technology. I believe that the Fangguan market will be better and better in the future.
One of the steps that are prone to defects in the production of square tubes is heat treatment and the other is tensile treatment. Today we need to know the latter. Maybe some people will have a lot of questions about why square tubes are prone to defects in tensile. Now let's analyze the specific causes of defects.
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.
Therefore, the drawing process of square tube is quite meticulous. For a long time, square tube, seamless square tube, galvanized square tube, galvanized tube and other brand products are provided with complete designated products and quality assurance. In the process of continuous development, square tube has also been processed more rigorously.
equipment maintenance .Stainless steel q355b square pipe for fluid transportation Standard No.: gbt12771-1991. The representative materials are 0Cr 0cr19ni 00cr19ni 00cr1 0cr18ni11nb, 0017cr17ni14mo2, etc. It is mainly used to transport low-pressure corrosive media.
Q355b square tube is a kind of hollow square section steel square tube, also known as hollow cold-formed section steel. It is a section steel with square section shape and size made of hot-rolled or cold-rolled strip or coil plate after cold bending and high-frequency welding.
How to reduce the amount of oxide scale is the key to the heating operation of seamless square tube. Especially when it's hot. Starting from the service life of tools and the surface quality of pipes, the requirements are more stringent. For example, hot furnaces are divided into heating furnace and reheating furnace according to their functions; The former is used to heat the blank from normal temperature to processing temperature; The latter is used to reheat the blank to the necessary processing temperature during processing.
Large diameter welded square pipe for low pressure fluid transmission, Standard No.: gbt14980-1994. Representative material: q235ab grade. It is mainly used to transport low-pressure fluids, such as water, sewage, gas, air and heating steam.
demand.The 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, it will automatically alarm and spray marks. The production will adjust the process parameters at any time to eliminate the defects in time.
Square pipe for conveying flammable and non flammable fluids, Standard No.: gbt97 1 (gbt97 - 1997). The representative material is l245-l4 pipeline steel. It is mainly used to transport flammable and non flammable fluids. Low pressure or high pressure square pipes have high requirements. The purpose of large-diameter q355b square pipe is q355b square pipe, C-shaped steel and H-shaped steel. It is mainly used in the construction of simple plant, steel structure and other infrastructure. Q355b square pipe is generally used as the frame and purlin of the plant. C-shaped steel Steel is an important support for the plant, and H-section steel is used as load-bearing. Especially in recent years, a large number of small and medium-sized enterprises have started to build spacious and bright plants. If traditional buildings are built, the time is slow, and the investment is large. For some small and medium-sized enterprises, if the investment in the plant is too high, the capital will be produced after operation Serious impact. The plant built with q355b square tube, C-section steel and H-section steel has the characteristics of time saving, money saving and fast use. Therefore, the sales of q355b square tube, C-section steel and H-section steel have increased significantly in recent years and become the first choice for plant construction. Q355b square tube, C-section steel and H-section steel are mainly used in the construction of simple plant, steel structure and other infrastructure The q355b square tube is used as the frame and purlin of the plant. The C-shaped steel is used as the important support of the plant, and the H-shaped steel is used as the load-bearing. Especially in recent years, a large number of small and medium-sized enterprises around the country have started to build spacious and bright plants. If the traditional buildings are built, the time is slow, the work progress is affected and the investment is large. For some small and medium-sized enterprises Said that if the investment in the plant is too high, C-section steel and H-section steel has the characteristics of time saving, money saving and fast use. Therefore, the sales of q355b square pipe, C-section steel and H-section steel have increased significantly in recent years, becoming the first choice for plant construction. Large diameter q355b square pipe plant is introduced Shao measures for effective wrinkle of seamless square pipe: check the wrinkle state, even when the wrinkle around the part is determined to be less than the clamping force, and the gradual increase of the roll gap force can be. When drawing the cone and hemispherical components, it should be increased to increase the inner diameter of the inner plate and the tensile stress of the wrinkle drawbead. Adopt the principle of loosening after tightening to loosen after tightening and ask Question.
In the case of dynamic load, plastic design usually calculates the allowable stress according to the safety factor that the allowable stress is not less than the dynamic load and multiplied by the allowable stress. In the case of bending of an axis, it can be calculated by the formula a = W. replacing the calculated strength with plasticity can improve the bearing capacity of the member by 14%.
Aurora.In terms of hot working, repeated upsetting and multi-directional rolling of ingot can not only reduce the level of carbide segregation in square tube, but also improve the anisotropy of steel.
After aluminum deoxidation in molten steel, & omega; When (ALS) is 0.015% ~ 0.025% calcium treatment can achieve better effect on the denaturation of Al203.
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 bending can also bend the inner corner of r0.2t without fracture of pipe wall. The disadvantage of empty bending is that when the upper side and side are synchronous empty bending, due to the pressure generated by the upper roll and the lower roll at the same time, the forming force is easy to exceed the critical point, resulting in edge instability and concave, and will also affect the stable operation of the unit and forming quality. This is also the different characteristics of q355b square tube and round tube empty bending.