Spiral Welded Pipe Cold Cracking Causes

In fact, after rolling cold - process cooling to room temperature process that species. The actual production is often used to control rolling and cold-known properties of the steel segment to control the organization needed a tree. Temperature and transformed organization apparently cooling rate Qin cold austenite transformation will produce a significant increase from the shadow of austenite from ferrite - cementite mix to the more detailed high hardness also been training accordingly formed fine pearlite, a very special song and bainite light Mu and other organizations. Ductility and poor thermal conductivity of steel, causes cooling process prone to cold dagger and white pattern of cold cracking is not exactly 'the former forming force (the stress) exists, but mainly due to the atmosphere of the latter but mainly due to the impact of stress in the steel. Steel so they arrest; thermal conductivity and worse song of stress are greater, the more prone to poor grades, especially in the city, such as high-speed steel alloy, steel, higher, do not prone to cold cracking. But previously mentioned, it does not mark these high alloy steels technical requirements and characteristics should be used after hot rolling after hot Sapporo different cooling methods are commonly used in cooling water cooling, air cooling, stack cooling, slow cooling steel cooling requires not only controlling the cooling rate, but also to seek to cool the steel are likely to cause this distortion and tissue defects such as uneven performance. Rapidly cooling the wire rod mill finished by water jacket close to the phase transition temperature, the loop forming guide means is introduced (spinning machine), a wire loop in succession while continuously moving off the conveyor chain, so that each ring separated certain distance from scattered circle. Depending on different steel, available in the transport process forced cooling fan, or natural air cooling, or add cold hood to control the microstructure and properties of the wire. For these purposes, conveyor speed is adjustable. After the intersection when the material is cooled to complete the loop temperature of 550 to 4500, the volume is set to close by and small bales. After a short wire rolling to the Secretary forced cooling, the wire surface temperature dropped sharply beginning martensitic transition temperature, the surface layer of spiral welded steel manufacturers to produce martensite in the wire after the cooling section, the use of center and part of the residual heat from the heat released from the phase change of the surface layer the wire temperature rises and reaches an equilibrium temperature, the surface martensite. Finally get center sorbitic surface of tempered martensite.