热轧镶钢机械刀片的焊缝和母材的组织及性能

Microstructure and Properties of Weld Joint and Base Materials of Machinery Knives by Hot Rolling-Jointing

研究了热轧焊接镶钢机械刀片的焊缝和母材的组织及性能。结果表明,热轧焊接镶钢经热处理之后,刃钢与刀体已完全冶金结合在一起;合金钢刃钢的显微组织细化均匀,是以最佳的热处理工艺为保证的;Q235钢刀体显微组织复杂,与热轧镶钢工艺和随后的热处理工艺均有关。焊缝剪切强度通常为196~343 MPa,焊缝碳扩散层较深,提高焊缝强度的关键是降低焊线的夹杂和气孔率。依照热轧焊接机理分析认为,提高加热温度和加大压轧变形量都有利于结合面的固相焊接,合理的温度和轧下量不仅是获得优良显微组织的要求,也是降低能源消耗和轧机功率的需要。

The microstructure and properties of weld joint and base materials of machinery knives by hot rolling-jointing were researched. The results show that the metallurgy j ointing of the blade steel and knife body already have been complet- ed by hot rolling-jointing and heat treatment. The microstructure of the blade steels is fine and uniform owing to the best heat treatment. The microstructure of Q235 steel knife body is complicated depending on both hot rolling-jointing process and heat treatment process. The shear strength of the weld joint generally is 196-343 MPa and the carbon diffusion layer of the weld joint is very deep, and the key of increasing welding strength is decreasing the impurity and air hole in the weld joint. The analysis based on hot rolling-jointing mechanism discussion show that the raising temperature and increasing press ratio are both advantageous to increase welding strength, but appropriate temperature and rational press ratio are not only the request of excellent microstructure but also the need to debase dissipative hot energy and rolling mill power.