To sum up improving the quality level of square tube is the key to ensure the service life of die. Therefore， when the economic cost and equipment conditions permit， the quality level of square tube， including surface quality and internal quality， oil， heating and other pipelines.
jWelding is a synthetic gradient material，Q345D square tube which can be used as solder to weld special-shaped materials in order to overcome the mismatch of chemical mechanical and physical properties between base metals.
Section shape classification square tube is classified according to section shape: simple section square tube: square tube，160 galvanized square pipeThere is no market after laying eggs under the nest rectangular square tube.
FPascaniFrom 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， reasonable process procedures should be selected from an economic point of view. Obviously， 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.
BhStrength structural steel， adding main alloy elements such as manganese， silicon，Q345D square tube vanadium， niobium and titanium; Its total alloy content is %. According to the strength， it is divided into four levels: ， ， and MPa.
The cut-off position shall match the construction and site conditions， draw the determined position and mark the cut-off line with a meter ruler or other measuring tools.
Square tube with complex section: flower shaped square tube， open square tube， corrugated square tube and special-shaped square tube.
eThe inspection items， sampling quantity， hot-rolled square tubes can be sampled in batches according to the rolled root array.
JApplication of square tube products: for mechanical equipment，Q345D square tube solar energy equipment， steel structure，160 galvanized square pipeThere is no market after laying eggs under the nest automobile parts， bridge ground pile， guardrail and ship internal structure.
TmiddlemanThe 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.
mFCommon specifications of square tube: ~ & times; × .～ × × .～ × × .～ × × .～ × × ～ × × ～ × × ～ × × ～ × × ～ × × ～ × × ～ × × ～ × × ～ × × ～ × × ～ × × ～ × × ～ × × ～ × × ～ × × ～ × × ～
When we understand the causes of defects in the drawing process of qb square tube， we should constantly improve the technology in the subsequent production process，Square pipe, square rectangular pipe, seamless square pipe, galvanized square pipe, galvanized pipe - Wuxi Jiahang metal products Co., Ltd so that we can reduce the occurrence of defects.
Compared with other traditional pipes， square pipe supply steel pipe has lighter raw materials， high strength， good resistance， can withstand high internal pressure， sensitive application， and can get used to messy or bad geological conditions.
PriceuSection shape classification square tube is classified according to section shape: simple section square tube: square tube， rectangular square tube.
XIn this period， the technology of continuous rolling pipe was not mature.
Polishing process of square tube square tube is widely used in our life， so in the subsequent application process， 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.
wIn & 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， mm.
xCThe inner and outer walls of the pipe shall retain the original surface without any processing.
The analytical technology of square tube sizing rolling. When sizing rolling is adopted， because there is no tool on the inner surface， the shape of the inner surface of the rolled material is not neat when rolling the tube. When the roll mill is used， the inner surface of the rolled material is angular. The occurrence mechanism of this phenomenon and the countermeasures to be taken are clarified by using the three-dimensional finite element method.