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.Alloy steel pipe is a new type of seamless steel pipe connection pipeline. The selection of pipeline connection pipeline, whether it is fire water system software, water supply equipment, or pipeline, heat and national defense industrial pipeline system software of petrochemical pipeline system, alloy steel pipe stimulates important effects.Chikimulia,The use of welded steel mesh in China is still in its infancy. At present, the use of welded steel mesh in China accounts for less than one of the total amount of steel reinforcement. In the early s, steel welded mesh was listed as a key implementation project by the science and Technology Commission and the Ministry of construction, and specifications and procedures were formulated.The shape of small longitudinal crack on the surface of alloy pipe is less than mm The overall width is less than mm The depth is lower than .mm.Sedhiou,After the passivation treatment of alloy pipe, it is clearly proposed that water cleaning shall be carried out immediately after the aqueous solution, ~ times of water cleaning,ChikimuliaLarge diameter high pressure alloy pipe, and then chromic acid closed solution shall be carried out. Chromic acid solution must be carried out h after the subsequent water cleaning of metallographic structure and austenitic alloy pipe. Chromic acid aqueous solution (mass ratio) is % ~ % the solution temperature is ~ ℃, and the solution time is min. Then dry.I-beam is mainly used in building structure, curtain wall engineering, 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, under the action of thermal stress, 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, i.e. the transformation from austenite to martensite, 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.Galvanized 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, 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. Good comprehensive mechanical properties, weldability, cold and hot workability and corrosion resistance, and good low temperature toughness.When selecting I-beam in structural design, reasonable I-beam shall be selected according to its mechanical properties,ChikimuliaWhat is the price of 273 seamless pipe, chemical properties, weldability and structural size. I-beam is mainly divided into ordinary I-beam light I-beam and wide flange I-beam. According to the height ratio of flange to web, it is divided into wide, medium and narrow flange I-beams.total cost,H-section steelWhether 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.Classification introduction

Miscellaneous scabManufacturing cost, The small length of repair welding is mm; The raw material shall not exceed mm after grinding by welding edge. According to the purpose, the welded pipe has general purpose and high temperature and high pressure. The pipe used in the latter is often special alloy steel. The problem of shrinkage cracks in the welding process and the mechanical properties of the pipe in the heat affected zone must be considered and solved, and the mechanical properties of the pipe in the heat affected zone will not be greatly changed due to the influence of welding operation.Ways to obtain surface compressive stress characteristics of alloy tubesChikimulia,I-beam features: the content of chromium carbon alloy is -%, the hardness of chromium carbide alloy is V, and the macro hardness is - HRCWhether I-section steel is ordinary or light, because the section size is relatively high and narrow,Chikimulia27SiMn large diameter seamless pipe, the moment of inertia of the two main axes of the section is quite different, so it can only be directly used for members bent in the plane of their web or form lattice stressed 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. I-beam is widely used in buildings or other metal structures.The wear resistance, 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.