表面技术2023，Vol.52Issue(12)：65-73,9.DOI:10.16490/j.cnki.issn.1001-3660.2023.12.005
渗碳辅助磨削强化表面创成机制研究
Strengthening Surface Generation Mechanism of Carburization-assisted Grinding
摘要
Abstract
The grinding surface with high machining quality and superior physical properties is in urgent demand,but most existing manufacturing methods have limitations in manufacturing cost and efficiency.Therefore,a carburization-assisted grinding method is proposed.It is an advanced surface modification technology,which can significantly improve surface properties,such as wear resistance,hardness,and roughness.Based on experiment and theoretical analysis,the dynamic strengthening and removal mechanism of surface materials in carburization-assisted grinding were explored. Using 20CrMnTi as the research object,exploratory experiments were conducted on carburization-assisted grinding to analyze the feasibility of grinding micro carburization.The workpiece surface required carbon coating as the external diffusion source.This coating was a carbon paste product after dehydration,containing three ingredients:carbon source,branched-chain starch,and polyvinyl alcohol solution.After the pre-processing of the grinding surface,carburization-assisted grinding tests were conducted on the experimental platform,and a temperature acquisition system(TOPRIE TP700)was utilized,which was suitable for synchronous measurement of the temperature.The sizeable grinding depth and the low feeding rate were selected for the test condition without any cooling system,(the maximum grinding depth of up to 250 µm and the slowest feeding rate of only 0.01 m/s),which could make the austenitizing transformation more thorough.The specimens were observed with a scanning electron microscope(SEM),and the carbon concentrations at different locations were detected with an energy dispersive spectrometer(EDS).Experimental results showed that the micro carburization effect in the contact zone increased the surface carbon content,making it easier for the surface to precipitate strengthening phases during the cooling stage. Based on the interaction between abrasive particles and materials,a dynamic surface generation mechanism was proposed to analyze the carburization effect of the carburized surface.In the grinding contact area,the morphology of grits and interstices could affect the material flow.The plowing and cutting stage existed at the same time,and the formation of grooves,ridges,and chips on the grinding surface was dynamic.The micro carburization in the contact area increased the carbon concentration of the grinding surface.For mild steel,this effect could significantly increase the hardness and reduce the plasticity of the surface.As a result,the extent and height of the ridge were reduced,and the plowing effect was diminished.The carbon coating was broken to produce carbonaceous particles,and the rotating wheel squeezed these particles into the interstice to occupy the material flow space,so chips were more easily produced. Finally,combined with a carburization-assisted grinding experiment,the properties and morphology's enhancement effect on the carburization surface were verified.The hardness of the grinding surface was measured with a Vickers hardness tester HTV-5S.The roughness Ra could be calculated based on the values of the surface profile at the cross-sections with a laser confocal microscope LEXT OLS4100.This method could effectively improve the hardness of the machined surface(maximum enhancement rate 60%),and surface accuracy(Ra reduced by 0.3 µm). In summary,a new carburization-assisted grinding method is proposed to address the surface generation and strengthening issues of low-carbon steel,which can achieve micro carburization of surface materials.Under intense grinding heat,the surface material undergoes austenite-martensitic transformation,which can significantly improve hardness.Meanwhile,micro carburization weakens the plasticity of surface materials,which can also improve surface accuracy.关键词
渗碳辅助磨削/表面创成/微渗碳效应/高性能表面制备Key words
carburization-assisted grinding/surface generation/micro carburization effect/high performance surface manufacturing分类
金属材料引用本文复制引用
徐春伟,张贺,修世超,洪远,孙聪..渗碳辅助磨削强化表面创成机制研究[J].表面技术,2023,52(12):65-73,9.基金项目
国家自然科学基金(52175383,52105433)National Natural Science Foundation of China(52175383,52105433) （52175383,52105433）
