What harm does hydrogen have in steelmaking of intermediate frequency furnace?
Author：www.wanf.cn Time：2018-12-19 10:08
Hydrogen is a common harmful gas in steel.If the content exceeds the safe content, the performance of steel will be adversely affected.The harmful effect of hydrogen on steel is mainly shown in the following points.
1. Hydrogen embrittlement of steel
Hydrogen embrittlement mainly shows that the elongation and section shrinkage of steel decrease obviously.Generally, the higher the tensile strength, the greater the hydrogen embrittlement sensitivity of steel.Hydrogen embrittlement is the most harmful to martensitic steel, and austenitic steel is not sensitive to hydrogen embrittlement.Hydrogen embrittlement of steel occurs in a certain stress, after a period of time, steel suddenly brittle fracture.
2. Make the steel produce white spots
Too much hydrogen in steel, along the steel cross-section fracture will appear round or oval silver bright and shiny spots.The essence of the white spot is the extremely fine crack of hydrogen content, which destroys the continuity of the metal and reduces its transverse tensile strength, section shrinkage and elongation, and finally leads to scrap just now.
3, make the ingot internal bubbles and cracks
Since the solubility of hydrogen in molten steel is higher than that in solid steel, when the hydrogen content in molten steel is too high, a large amount of hydrogen will precipitate out in the solidification process of ingots, which will lead to the rise of steel nails and the formation of pores and cracks inside the steel nails, and finally make the ingots useless.Most of these defects occur in the atmospheric induction furnace smelting nickel - based alloy.
4. Crack is generated in the heat affected zone of welding seam
In the process of welding, the weld metal absorbs a large amount of hydrogen from the humid welding material in the atmosphere.With the cooling and shrinkage of the metal in the weld zone, cracks are generated by the continuous expansion of cracks.
Because the harm of hydrogen in steel is multifaceted and serious, the content of hydrogen in steel should be reduced as far as possible in the process of intermediate frequency furnace smelting.