The disadvantage of solid bending is that it has tensile thinning effect. The actual bending will produce tension at the bending point， 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.
8You can really feel that the square tube is widely used in the development， and qb square tube factory continues to extend in the technical level， which makes the current square tube develop more widely.
oWhen the vehicle is replaced with seamless square tube blank， the material is too soft to affect the requirements so as to ensure the quality of parts and avoid wrinkles.
As for the color treatment technology of qb square tube， the application of color qb square tube treatment technology includes chemical method and electrochemical method from the process point of view. They can get different colors by treatment in specific electrolyte，Q345B square tube so as to improve the wear resistance，Galvanized square pipe 30Convenience of color and variety of qb square tube， which can be applied to different occasions and obtain different economic benefits.
PThonexApplication of square tube products: for mechanical equipment， solar energy equipment， steel structure， automobile parts， guardrail and ship internal structure.
OyIt is recommended that the galvanized surface be primed with epoxy zinc yellow primer.
Banded due to improper hot working temperature， that is， when the hot working stop forging temperature is in the phase zone (between， and )，Q345B square tube ferrite precipitates in bands from austenite along the metal flow direction， and the undigested austenite is cut into bands. When it is cooled to a， the banded austenite is transformed into banded pearlite. This can be improved or eliminated by increasing the final rolling temperature， increasing the forging ratio， diffusion annealing and normalizing.
From the perspective of production， we should give full play to the productivity of production equipment and reduce the consumption of fuel and equipment on the basis of meeting the size and performance requirements of qb square tube. Therefore， the temperature of no open forging and final forging is a comprehensive technical and economic problem. If qualified qb square tubes can be obtained in the temperature range of the vehicle， the higher the temperature the easier the forging and the higher the productivity， but the greater the fuel consumption and the loss of the heating furnace; We should consider these two aspects and make a reasonable choice.
mThe surface of fake and inferior square tubes is easy to produce scabs. There are two reasons: the material of fake and inferior square tubes is uneven and there are many impurities. The guide equipment of fake and shoddy material manufacturers is simple and easy to stick to steel. These impurities are easy to scar after biting the roll.
FThe analytical technology of square tube sizing rolling. When sizing rolling is adopted， because there is no tool on the inner surface，Q345B square tube the shape of the inner surface of the rolled material is not neat when rolling the tube. When the roll mill is used， the protective layer of seamless qb square tube can be chiseled and measured.
aEAfter chemical treatment and surface treatment of the square tube，Galvanized square pipe 30Convenience of 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.
Upper yield point (& sigma; Su): the 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.
Qb square tube， the die material selected has obvious hardening in the deep drawing process， resulting in a lot of hard metal points， resulting in adhesion. It specializes in selling square tube， square rectangular tube， seamless square tube， galvanized square tube，Galvanized pipe_ Galvanized square pipe_ Seamless steel pipe_ Square tube - Wuxi Jiahang galvanized tube and other special products. It is an old brand with advantageous price and guaranteed quality. It makes the surface of workpiece and die easy to be scratched and worn. Therefore， tool steel for general die can not be used.
planyAt the same time， hanging heating shall be carried out during heating to reduce quenching deformation. For high-precision guide rail， gas nitriding or ion nitriding shall be carried out to reduce deformation; Square tubes have outstanding performance in all aspects of performance. We will also test them in this regard when making square tubes more durable. What outstanding performance do square tubes have in mechanical properties? Next， Ill introduce it to you.
WThe principle is similar to that of the plate rolling machine. The bending machine can determine a circle. Adjust the height to adjust the curvature.
Qb 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.
pTherefore， QA is usually not preheated. However， when the plate is very thick， it should be preheated because it cools quickly. Once # steel was cracked by J welding. If the plate thickness is more than mm， there is a great risk of not preheating.
dQThe researchers test before using the strip thinning drawing also confirmed that using the strip thinning drawing can greatly reduce the large value of tangential residual stress of the drawn parts and effectively prevent the occurrence of longitudinal cracking. According to different deformation degree and original sheet thickness， the appropriate thinning coefficient & psi is selected; N (generally .t ~ .t)， if & psi; If n is too small， the deformation stress will increase sharply， resulting in the fracture of the bottom of the drawing part.
Large diameter welded square pipe for low pressure fluid transmission， Standard No.: gbt-. Representative material: grade qab. It is mainly used to transport low-pressure fluids such as water， sewage， gas， air and heating steam.