Study On The Hot Rolling Technology Of65Mn Saw Steel

Nowadays, it has been an important research subject for how to be fully exploitedthe performance of steel materials, to improve the quality of its use, and to extend its life,in order to enhance the utilization of energy and resources economic in nationalconstruction.65Mn steel is not only a more traditional saw material but also one ofcurrently main material types of saw blades. This article will apply controlled rolling andcontrolled cooling technology to the production of special steel65Mn blade process, andmake a detailed study of the hot rolling process and properties of variation, and at last itwill lay theoretical basis for the next generation of high-performance production of65Mnsteel blade.The main work and conclusions of this study, including:1）It optimizes the composition of65Mn steel blade, and raises the compositionroute of low carbon high manganese and high silicon based on the international standard.Experimental results show that such ingredients ensured the original strengthfundamentally, besides, and they have a significantly improved stability in toughness,hardenability and resistance of tempering, which will paly an important role in extendingthe service life and large-scale production.2） By dilatometric change referencing microscopic test and hardnessmeasurement,the different expanding curves of65Mn steel under different cooling ratewas determined in Gleeble-3500thermal mechanical simulator,and the dynamic CCTcurves were obtained. And it reaches the influence of cooling rate on steel microstructureand hardness was studied. The results show that the products of austenite transformationare ferrite and pearlite when the cooling rate is lower than10℃/s; those will be ferrite，pearlite and martensite when the cooling rate is in the range of10to40℃/s and thosewill be totally martensite if the cooling rate is higher than40℃/s.3）The hot deformation behavior of65Mn steel was simulated by Gleeble-3500thermal-mechanical simulator. The results show that the flow stress and peak strainincrease with the decrease of temperature and the increase of strain rate. Mathematicalmodel was established using regression analysis. The model of deformation resistance of65Mn steel was obtained with high fitting precision. 4） Controled rolling and controlled cooling experiments have been done atexperimental rolling mills.The effect of reheating temperature, starting temperature,finishing temperature, cooling rates，coiling temperature and cooling rates after coilingon microstructure and mechanical properties for65Mn steel has been investigated.Meanwhile, preliminarily determined the TMCP technological parameters of65Mn hotrolling.5）Through the trial production of industrial, the influence of different controlledrolling on the microstructure and properties of hot rolled65Mn steel was determined andthe best controlled rolling technology was established. The result shows that by this hotrolling process, then the quality of products has greatly improved.