The crack mainly occurs at -mm from the edge of the alloy pipe. The shape is several parallel vertical cracks of different sizes. The regularity is that the thicker the specification and model of the alloy pipe is The wider the width, the more serious the disadvantages. Mixed pass system. According to the characteristics of rolling mills and products, in order to give full play to the advantages of their respective systems and overcome their disadvantages, mixed pass system is often adopted, that is,KohutepecHow much is 50 welded pipe per meter, the combination of more than two systems. For example, straight leg cross rolling pass system is adopted for finished hole and front hole of finished product, and bent leg cross rolling system is adopted for other passes; or direct rolling system is adopted for rough rolling hole and straight rolling system is adopted for the last ~ finish rolling holes Leg oblique tie hole etc.Kohutepec,Galvanized steel pipe: in order to improve the corrosion resistance of steel pipe, the special rolling method can be used to make full use of the skills of uneven deformation and pass design. For example when the billet section is narrow and wide I-beam is required to be rolled, the wave rolling method can be used; for example, when the billet is wide and small I-beam is required to be rolled, the negative rolling method can be used Spread rolling, Peak crackUnder the action of thermal stress,KohutepecLarge diameter high pressure alloy pipe, because the initial temperature of the surface layer is lower than that of the heart and the shrinkage is greater than that of the heart, the heart is pulled. At the end of cooling, because the final cooling volume shrinkage of the heart cannot be carried out freely, the surface layer is compressed and the heart is pulled. That is, the surface of the workpiece is finally compressed and the center is pulled. This phenomenon is affected by factors such as cooling rate material composition and heat treatment process. The faster the cooling rate, the higher the carbon content and alloy composition, the greater the uneven plastic deformation caused by thermal stress during cooling, and the greater the final residual stress. On the other hand due to the change of microstructure during heat treatment, the increase of specific volume will be accompanied by the expansion of workpiece volume, and each part of workpiece will undergo phase transformation successively, resulting in inconsistent volume growth and structural stress. The final result of the change of tissue stress is the tensile stress on the surface and the compressive stress in the center, which is just opposite to the thermal stress. The microstructure stress is related to the cooling rate, shape and chemical composition of the workpiece in the martensitic transformation zone.→ compared with the concrete structure, the I-steel structure can increase the service area by %,KohutepecHow much is the I-beam of 16, reduce the self weight of the structure by % - %, and reduce the structural design internal force.

Miscellaneous scabGalvanized pipe is a kind of light thin-walled steel pipe 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 Q 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 extra thick wall galvanized pipe reach or even exceed the level of resistance welding cold formed galvanized pipe.I-beam is mainly used in building structure, curtain wall engineering, mechanical equipment and vehicle manufacturing.Price,The utility model has the advantages that the axial force of the roll is small, the axial movement is small, and the working slope is not required,After determining the reasonable pickling agent and polishing solution, it is very easy to carry out hot galvanizing for relevant alloy pipes. Use 'phosphating treatment' to degrease the pipes of electrolytic machine equipment, put them into the aqueous solution with zinc salt after pickling and passivation, connect the negative level of electrolytic machine equipment, put them into the cold-rolled steel plate in the direction corresponding to the pipes, and connect the switching power supply, If the current flows from the positive stage to the negative stage, a layer of zinc is deposited in the pipe.The section of I-beam has good straight pressure and tensile resistance, but the section size cannot resist torsion because the wing plate is too narrow. On the contrary, H steel has its own advantages and disadvantages.

H-beam is a widely used profile in steel structure buildings. It is different from I-beam. The first is the flange, and the second is that the inner surface of the flange has no inclination, and the upper and lower surfaces are parallel. The section characteristics of H-beam are obviously better than those of traditional I-beam, channel steel and angle steel.Economic management, Mixed pass system. According to the characteristics of rolling mills and products, in order to give full play to the advantages of their respective systems and overcome their disadvantages, mixed pass system is often adopted, that is, the combination of more than two systems. For example, straight leg cross rolling pass system is adopted for finished hole and front hole of finished product, and bent leg cross rolling system is adopted for other passes; or direct rolling system is adopted for rough rolling hole and straight rolling system is adopted for the last ~ finish rolling holes Leg oblique tie hole, I-beam is an I-shaped section steel. The inner surface of the upper and lower flanges has an inclination, generally : which makes the outer flange thin and the inner flange thick. Therefore, the section characteristics of I-beam in the two main planes are very different, and it is difficult to give full play to the strength characteristics in application. Although the thickened I-beam has also appeared in the I-beam market, the structure of the I-beam has determined its torsional performance.Kohutepec,The delivery length of I-beam is divided into fixed length and double length, and the allowable difference is specified in the corresponding standards. The length selection range of domestic I-beam is divided into -, - and - according to different specification numbers. The length selection range of imported I-beam is generally -.The wear resistance, fracture toughness, impact toughness and bending strength under different process conditions were compared, and then the heat treatment process of GCrMo was determined. Development and application of ZYS- bearing damping and antirust oil. Bearing is a new type of multial damping and antirust oil. It takes refined mineral oil as the base oil and is equipped with various additives such as antirust and antifriction. Through comparison test, matching test with lubricating grease and user test, it is proved that ZYS- bearing damping and antirust oil has outstanding damping effect and good antirust lubrication performance.Whether I-section steel is ordinary or light, due to the relatively high and narrow section size, there is a large difference in the moment of inertia between the two main sleeves of the section. Therefore, it can only be directly used for members bent in the plane of their web or form lattice stress members. It is not suitable for axial compression members or members with bending perpendicular to the web plane, which makes it very limited in the scope of application.