There are many processes in the processing of welded pipes. Every detail is something we need to pay attention to. You can find out about the heat treatment of welded steel pipes in welded pipe processing.
Welded steel pipes need to be processed through various processes before application. The heat treatment of welded steel pipes is an important part in the processing of welded steel pipes. Thermal processing is firstly a metal thermal processing process in which a metal material is heated, insulated, and cooled in a certain medium to control its metal properties by changing the metallographic structure of the surface or interior of the material.galvanized steel pipe
During the heating and cooling process of the structural welded steel pipe workpiece, due to the inconsistency between the cooling rate and the time of the surface layer and the core, a temperature difference is formed, which causes volume expansion and uneven shrinkage to generate stress, that is, thermal stress.
Under the action of thermal stress, since the surface layer starts to be lower than the core, the contraction is also larger than the core and the core is pulled. When the cooling is finished, the core is not free to contract due to the final cooling volume contraction of the core. Pulled. That is, under the action of thermal stress, the surface of the workpiece is finally pressed and the core 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 residual stress formed. On the other hand, in the process of heat treatment, when steel changes to austenite to martensite, the increase of specific volume is accompanied by the expansion of the volume of the workpiece, and the parts of the workpiece are successively transformed, resulting in inconsistent volume growth and tissue formation. stress. The final result of the change in tissue stress is the tensile stress on the surface layer and the compressive stress on the core, just opposite to the thermal stress. The magnitude of the tissue stress is related to the cooling rate, shape, and chemical composition of the workpiece in the martensitic transformation zone.galvanized steel coil manufacturers
In order to make the steel pipe workpiece have the required mechanical properties, physical properties and chemical properties, in addition to the rational selection of materials and seed forming processes, heat treatment processes are often essential. Steel is the most widely used material in the machinery industry. The microstructure of steel is complex and can be controlled by heat treatment. Therefore, the heat treatment of steel is the main content of metal heat treatment. In addition, aluminum, copper, magnesium, titanium, and the like can also be modified by heat treatment to obtain different mechanical properties, physical properties, and chemical properties.