Research On Quality Of Rod For Gear Steel 20CrMnTi In The Rolling Process

Based on Baosteel group Xinjiang BaYi Iron and Steel co.,LTD rod line factory production by small units 20CrMnTi gear steel steel grade,as a representative of the research to improve the surface quality,defect analysis corresponding to the bar.Relationship between the quality of continuous casting billet are about 20CrMnTi gear defect on the surface of the round steel bar,steel smelting and continuous casting process control process optimization and rolling hot upset forging cracking problems.In this paper,the author with the help of a spectrometer,scanning electron microscopy and other apparatus to study the forming mechanism of casting billet surface crack under think A1203 inclusions in molten steel solidification front enrichment caused the production of contiinuous casting slab surface crack;Steelmaking process was studied by means of adjusting control of end point P composition,with double slag or steel pour slag operation lower P content,adjust smelting steel tapping temperature,molten steel continuous casting process by increasing the nozzle diameter,the precise degree of superheat control scope,increase the protection pouring process improved measures such as to make casting quality,reducing gear steel 20CrMnTi slab core segregation,central loose,the surface bubbles and shrinkage cavity defects such as;Also studied the rolling of hot upset forging cracking reason,strengthen deoxidization effect before furnace steelmaking process,guarantee the stability of mould level,prevent the protective slag involved,at the same time do a good job in secondary cooling zone cooling intensity control.Field test results of study show that by making the effective implementation of the improvement measures,to solve the Xinjiang BaYi Iron and Steel co.,LTD rod line factory small profile unit rollintg gear steel 20CrMnTi round steel auality problem.