The effect of heat treatment after welding of steel structure bolts
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tempo de atualização : 2021-01-20 20:25:59
In the welding process of steel structural bolts, due to the uneven heating and cooling, welding stress will always be generated in the components after the welding work is completed. The existence of welding stress in the component will reduce the actual load-bearing capacity of the welded joint area and produce plastic deformation. In severe cases, it will also cause the damage of the component.
1.Post-welding hydrogen elimination treatment refers to the low-temperature heat treatment performed after the welding is completed, when the weld has not been cooled to below 100℃. The general specification is to heat to 200~350℃ and keep for 2-6 hours. The main function of post-welding hydrogen elimination treatment is to accelerate the escape of hydrogen in the weld and the heat-affected zone, and it is extremely effective in preventing weld cracks during low-alloy steel welding.
2.The method of stress relief heat treatment is to reduce the high temperature yield strength of the welded workpiece to achieve the purpose of reducing the welding stress. There are two commonly used methods: one is the overall high temperature tempering, that is, the whole weldment is put into a heating furnace, slowly heated to a certain temperature, then kept for a period of time, and finally cooled in the air or in the furnace. In this way, 80%-90% of welding stress can be eliminated. Another method is local high-temperature tempering, that is, only heating the weld and its nearby area, and then slowly cooling it to reduce the peak of the welding stress, so that the stress distribution is relatively gentle, and it can partially eliminate the welding stress.
