Abstract: Low frequency torsional vibration tapping is an effective method to solve the problem of tapping in difficult to cut materials. Tapping parameters affect tapping torque and service life of tap, and cutting angle is the key parameter. Experiments were conducted to study the lubrication mechanism and the influence of cutting angle on lubrication effect. Experimental results indicate that the separate type boundary lubrication mode greatly enhances the lubrication effect of cutting fluid and the lubrication effect decreases with the increase of cutting angle. To obtain good technological effect, the smaller cutting angle should be selected.

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Study on a Cu-Fe Weld Metal of Manual SHS Welding

Authors: Wen Tong Xin, Zhi Zun Li, Yong Sheng Wu, Li Feng Qu

Abstract: The paper presents a Fe-base manual SHS Welding material with CuO+Al and Fe2O3+Al being the thermit and adding ferroalloy materials for solving the problem of low mechanical properties of the manual SHS Welding joint. The structure and properties of the welded joint were studied. The results indicated that: the welding was fusion welding, and weld appearance is good. Cu-Fe alloy in the molten pool experiences liquid phase separation during rapid solidification, and the weld metal is macroscopically separated into one Fe-rich part and one Cu-rich part. Fe-rich phase is filled in the welding line. At the same time, tensile strength of the welded joint was close to 500 MPa, and impact toughness was close to 40J/cm2, and surface hardness was also close to HB350. It also indicated this technology can meet the need of repair of metal parts in field.

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