The heat generated in the grinding zone plays an important role in the phase transformation that would alter the residual stress formation and surface integrity of work materials. Heat flux model is one of the key factors in calculating the heat into work piece. A new heat flux model based on the grinding actions is developed to calculate the grinding heat. The heat flux profile in the new heat flux model is very important and is discussed in detail. The finite element method is used to simulate the temperature fields. The comparison between simulation results and experimental results indicates the reliability of the proposed model. The simulation result from triangle heat flux model provides agreement with the experimental result in large cutting depth, and the simulation result from new heat flux model provides agreement with the experimental result in small cutting depth. Heat flux models should be selected to simulate temperature fields in various grinding conditions. It is helpful to study on grind-hardening technology and forecast and prevention of surface burn.

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To investigate the impact of initial cracks on the fatigue performance of single lug and yoke joints, fatigue testing was performed for defective welding joint models. The crack extension behaviors were investigated based on the theories of fracture mechanics using ANSYS-FRANC3D interactive technology, and the effects of the initial crack location, morphology pattern, and surface angle on fatigue performance were determined. The results showed a fatigue failure mode in which the crack extended along the welding line for single lug and yoke joints. The fatigue life was shorter when the initial crack was in the corner of the single lug plate. Moreover, the crack growth rates during the early stage of crack extension varied significantly with different initial crack morphology patterns. However, the crack growth rates during the later stages were similar to one another. The remaining fatigue life increased with the shape ratio for the same crack depth. Finally, the crack growth rate was the fastest, and the remaining fatigue life was the shortest when the initial crack surface angle was inclined toward the stress concentration area.

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Grinding coolants have the functions of cooling, lubrication, cleaning and rust prevention in grinding process. To avoid the environment pollution, we should develop environmental protection grinding coolants. So it is important to research the performance evaluation for grinding coolants. In this paper, three different test methods for grinding performance evaluation of grinding coolants are used to investigate the influence of three coolants on grinding process. The three test methods are four balls test, tapping torque test and real grinding test. The test results showed that the mechanism of four balls test is simple, and the test results have good repeatability, but there is a large divagation with real grinding test results. The tapping torque test has a good relativity with cutting process. The real grinding test is the best test method for grinding performance evaluation.