YAG laser welding with surface activating flux has been investigated, and the influencing factors and mechanism are discussed. The results show that both surface activating flux and surface active element S have fanta...YAG laser welding with surface activating flux has been investigated, and the influencing factors and mechanism are discussed. The results show that both surface activating flux and surface active element S have fantastic effects on the YAG laser weld shape, that is to obviously increase the weld penetration and D/W ratio in various welding conditions. The mechanism is thought to be the change of weld pool surface tension temperature coefficient, thus, the change of fluid flow pattern in weld pool due to the flux.展开更多
In this study, WC-Co powder with WC submicron grain size of 0. 7 - 0. 9μm was used as feedstock powder to deposit wear resistant coating by home-made T J-9000 HVOF system. The deposition efficiency of the feedstock p...In this study, WC-Co powder with WC submicron grain size of 0. 7 - 0. 9μm was used as feedstock powder to deposit wear resistant coating by home-made T J-9000 HVOF system. The deposition efficiency of the feedstock powder was examined. Influences of the High Velocity Oxy-Fuel （HVOF） spraying parameters on the microstructures, phase compositions, microhardness, and wear resistance of sprayed coatings were investigated. The deposition efficiency of the feedstock powder was very high, and reached to 58%. The sprayed coatings were very dense, and their porosities were lower than 1% and could be lowered than 0. 42% with optimal spraying parameters. According to the X-ray Diffraction （ XRD ） analysis, the phase compositions of the sprayed coatings consisted of WC, Co, W2 C, and Co6 W6 C. W appeared at high flame power. The average microhardness of the coating was 1 100 HVo 1 and had reversely linear relationship with the porosity of coatings. The weight loss of the counter wear ring GCrl5 was 20 times than that of the sprayed WC-Co coating. At the load of 15 kg and rotational speed of 200 r/min of GCr15 counter wear ring, the friction coefficient was 0. 68 in the dry wear conditions. It was concluded that the sprayed submicron structural WC-12Co coating had good wear resistance.展开更多
文摘YAG laser welding with surface activating flux has been investigated, and the influencing factors and mechanism are discussed. The results show that both surface activating flux and surface active element S have fantastic effects on the YAG laser weld shape, that is to obviously increase the weld penetration and D/W ratio in various welding conditions. The mechanism is thought to be the change of weld pool surface tension temperature coefficient, thus, the change of fluid flow pattern in weld pool due to the flux.
文摘In this study, WC-Co powder with WC submicron grain size of 0. 7 - 0. 9μm was used as feedstock powder to deposit wear resistant coating by home-made T J-9000 HVOF system. The deposition efficiency of the feedstock powder was examined. Influences of the High Velocity Oxy-Fuel （HVOF） spraying parameters on the microstructures, phase compositions, microhardness, and wear resistance of sprayed coatings were investigated. The deposition efficiency of the feedstock powder was very high, and reached to 58%. The sprayed coatings were very dense, and their porosities were lower than 1% and could be lowered than 0. 42% with optimal spraying parameters. According to the X-ray Diffraction （ XRD ） analysis, the phase compositions of the sprayed coatings consisted of WC, Co, W2 C, and Co6 W6 C. W appeared at high flame power. The average microhardness of the coating was 1 100 HVo 1 and had reversely linear relationship with the porosity of coatings. The weight loss of the counter wear ring GCrl5 was 20 times than that of the sprayed WC-Co coating. At the load of 15 kg and rotational speed of 200 r/min of GCr15 counter wear ring, the friction coefficient was 0. 68 in the dry wear conditions. It was concluded that the sprayed submicron structural WC-12Co coating had good wear resistance.
