Papers by Keyword: Grinding Hardening

Abstract: The high temperature in grinding hardening induces workpiece thermal deformation. The thermal deformation causes a concavity on the ground profile and affects the grinding hardening depth. The paper uses ANSYS thermo-mechanical coupling module to simulate the thermal deformation in grinding hardening. The workpiece profile by simulated is compared with the test result.

Abstract: In grinding hardening process, part’s surface (grinding zone) temperature directly affects the quality of surface layer of heat treatment. The high temperature heat pipe is very good device of control heat transfer. In order to make the grinding zone temperature slightly change in grinding process, this paper describes a design of temperature automatic control technology. A high temperature heat pipe contact with the part’s grinding zone. The zone temperature is measured using infrared radiation pyrometer and the temperature data will be used to control the high temperature heat pipe’s thermal resistance through the PID controller. That is that the PID controller will adjust the contact area between part and high temperature heat pipe, thus achieves control of part’s surface hardening requirements.

Abstract: A finite element heat transfer model incorporating a moving heat source has been developed to predict the temperature field in traverse cylindrical grinding. The model was then applied to analyse the grinding-hardening of quenchable steel 1045. It was found that in the region where the grinding wheel had an entire contact with the workpiece, material would experience a heating-cooling cycle, enabling the generation of a uniform hardened layer. In the transient regions at the two ends of the workpiece where the wheel-workpiece contacts were partial, the material was not hardened but experienced an annealing process. The results were in good agreement with the experimental observations.

Abstract: A three-dimensional finite element heat transfer model incorporating a moving heat source was developed to investigate the heat transfer mechanism in grinding-hardening of a cylindrical component. The model was applied to analyze the grinding-hardening of quenchable steel 1045 by two grinding methods, traverse and plunge grinding. It was found that the heat generated can promote the martensitic phase transformation in the ground workpiece. As a result, a hardened layer with a uniform thickness can be produced by traverse grinding. However, the layer thickness generated by plunge grinding varies circumferentially. The results are in good agreement with the experimental observations.

Abstract: This paper investigates the temperature field in plunge cylindrical grinding with the aid of the finite element analysis. The analysis included the effect of the variation of the depth of cut and that of the repeated heating and cooling caused by workpiece rotation. It was found that the predictions agree well with the experimentally measured results. The analysis showed that the heating in the consequent rotations further raises the temperature in the workpiece. The reheating in the hardened layer can lead to material’s tempering.

Abstract: This paper presents a temperature-dependent finite element heat transfer model, incorporating a triangular moving heat source and various cooling conditions, to predict the three-dimensional temperature field in plunge surface grinding. The model was applied to analyse the grinding-hardening of quenchable steel 1045 using dry air and liquid nitrogen as the cooling media. The temperature field variation under such grinding conditions was also measured experimentally. It was found that the temperature history predicted by the model agrees well with the measured results. The model provides a fundamental study as a first step in optimisation and control of the hardened layer thickness and its compositions in grinding-hardening technology.

Abstract: The grinding hardening is a new surface heat treatment technology using grinding heat in which induce martensitic phase transformation in the surface layers of annealed or tempered steels to achieve surface strengthening processes and integrate the surface hardening process with the grinding precision machining. In the paper, a thermal model to describe this process has been presented from the thermal partition modeling and has been used to predict subsurface time–temperature profiles in the dry cylindrical grinding crankshaft using cubic boron nitride (CBN) wheels. The grinding hardening experiment was carried out in precision cylindrical grinder M1420E, using work-piece material 42CrMo4 and CBN grinding wheel under dry grinding condition. The experimental results showed the theoretical model is agreement with experimental results and the model can well forecast the grinding hardening depths.

Abstract: The grind-hardening process integrates heat treatment processing into the production line, reduces the number of producing procedures, shortens machining period and lowers the cost. Meanwhile, grind-hardening machining doesn’t use cutting fluid. So the grind-hardening process is a green manufacturing method with an extending application in future. Grinding hardening is an effective method in machining SKD-11 hardened steel due to its good quenched property. In this paper, the grind-hardening characteristics of SKD-11 hardened steel are discussed, and the impacts on the hardened surface layer varying with the grinding parameters are also studied. Optimization of grinding parameters of SKD-11 hardened steel is conducted based on the study.

Abstract: Grind-hardening was done on Steel AISI 1066 with a conventional surface grinder and a corundum grinding wheel, and research was conducted to probe into structures and properties of the hardened layer under varied depth of cut and cooling conditions. Results show that the hardened layer do not change noticeably in their martensitic structures and micro-hardness, which is ranged between 810
870HV; But when the depth of cut increased or the dry grinding technique is adopted, the concentration of martensites and carbonides becomes lower, while the amount of residual austenites increases, and the completely hardened zone gets thicker. This conclusion serves as an experimental basis for the active control of properties of the grind-hardened layer of Steel AISI 1066.

Abstract: The current surface strengthening process of microalloyed unquenched and tempered steel components is usually induction or laser quenching treatment. Subsequent to heat treatment, these structural parts are subjected to grinding, during which impairment of hardened materials can be caused by thermo-mechanical influence of the grinding process. This paper studies a new method of surface heat treatment by making use of grinding heat and stress to create favorable microstructures and promote high wear and fatigue resistance. This work outlines the influence of grinding parameters on the superficial hardening effect of 48MnV microalloyed steel. It was found that the thickness and hardness of the treated surface layer could be up to 1.6mm and HV750 respectively. The beneficial microstructure of the layer was created by an enhanced martensite transformation. It is highly possible that the method can be used to incorporate grinding and surface hardening into a single grinding operation to develop a cost-effective production method.