Sharing China-Made with Global Customers
Sharing China-Made with Global Customers
High carbon steel refers to the carbon steel with w (c) higher than 0.6%, which has a greater hardenability tendency, is sensitive to the formation of cold cracks, and the weldability of high carbon steel is poor. Special welding process is needed to ensure the joint performance. In welding structure, it is rarely used.
High carbon steel is mainly used for machine parts requiring high hardness and wear resistance. In heavy machinery manufacturing, welding problems of high carbon steel parts will also be encountered. During welding process of high carbon steel, comprehensive analysis of possible welding defects should be made and corresponding welding measures should be taken.
Weldability of high carbon steel
1.Welding method
High carbon steel is mainly used for structures with high hardness and wear resistance. The welding methods include submerged arc welding, shielded metal arc welding and brazing.
2.Welding materials
High carbon steel welding generally does not need the strength of joint and base metal. Low hydrogen electrode with strong desulfurization ability, low hydrogen content in metal and good toughness shall be selected for shielded metal arc welding. If the strength of weld metal and base metal is required, low hydrogen electrode with corresponding grade shall be selected. If it is not required, low hydrogen electrode with strength grade lower than base metal shall be selected. If the base metal is not allowed to preheat during welding, Austenitic stainless steel welding rod with heat affected zone can be used to prevent cold cracking and obtain austenite structure with strong crack resistance and good plasticity.
3.Groove preparation
Reduce the fusion ratio, limit the carbon content in the weld metal, use U-shaped or V-shaped groove when welding, and pay attention to cleaning the oil and rust on both sides of the groove.
4.Preheating
The welding rod of structural steel should be preheated before welding, and the temperature should be controlled between 250 ℃ and 350 ℃.
5.Interlayer treatment
In multi-layer and multi pass welding, small diameter electrode and small current welding are used in the first pass welding. Usually, the workpiece is placed in semi vertical welding or the welding rod is used to swing horizontally, and the whole heat affected zone is heated in a short time to obtain preheating and heat preservation effect.
6.post welding heat treatment
After welding, the workpiece is put into the heating furnace for stress removal annealing, and the temperature is maintained at 650 ℃.
Due to the high carbon steel, high carbon content, poor weldability, welding cracks are easy to occur. Therefore, it is necessary to select a reasonable welding process to reduce the occurrence of welding cracks and enhance the performance of welded joints.
English
Español
