High Carbon Steel Welding Defects and Preventive Measures
As high carbon steel tends to be hardened, it is easy to appear hot and cold cracks during welding.
Measures to prevent thermal cracking
- Control the chemical composition of the weld, strictly control the content of sulfur and phosphorus, increase the content of manganese, in order to improve the weld structure and reduce segregation.
- Control the cross-section shape of the weld, width-depth ratio is slightly larger to avoid segregation of the weld center.
- Suitable welding parameters, welding sequence and welding direction should be selected for high rigidity welding parts.
- When necessary, take pre-heating and slow cooling measures to prevent the formation of hot cracks.
- Improve the alkalinity of electrode or flux, in order to reduce the impurity content in the weld, improve the segregation degree.
High Carbon Steel Welding
Prevention of cold cracking
- Preheating before welding and cooling after welding can not only reduce the hardness and brittleness of haz, but also accelerate the hydrogen diffusion in weld.
- Select proper welding procedure.
- Adopting proper assembly and welding sequence can reduce the restraint stress of welding joint and improve the stress state of welding parts.
- Select the appropriate welding materials, welding before drying electrode, flux, and do take with the use.
- Before welding should be carefully removed around the groove of the basic metal surface of water, rust and other contaminants, in order to reduce the diffusion of hydrogen in the weld.
- Hydrogen removal should be carried out immediately before welding so that hydrogen can escape fully from the welded joint.
After welding, the stress relief annealing treatment should be carried out immediately to promote the hydrogen diffusion in the weld.
High carbon steel is easy to produce high carbon martensite structure and welding crack because of its high carbon content, high hardenability and poor weldability, the corresponding measures are taken to reduce the occurrence of welding crack and improve the performance of welding joint.
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