Papers by Author: Shao Xiang Hao

Abstract: The main failure forms of whetstones forming die is serious wear on the work face, and the boronizing technology can be used to improve the hardness and wear resistance on the work face of the whetstones forming die. In this paper, the orthogonal test was used to obtain the optimum parameters of temperature, time and the amount of addition of rare earth in the boronizing process of die. The line scan spectrum shows that there are some of elements such as B, C, Al, Cr, Si and Fe etc in boronizing layer, and their content are changed during boronizing. The microhardness of boronization layer was measured, and the result showed that maximum value of microhardness of boronizing layer appears in subsurface, not in surface, and lowers along depth of boronizing layer. By comparing different wear curve of abrasive samples with different treated, we can see that the highest wear resistance of surface is in the sample with the optimization of boronization treatment +970°C quenching and 200°C tempering; followed by quenching and tempering treatment; the lowest wear resistance of the surface is the sample without the boronizing treatment, and the rest sample are between these two samples. After optimization of boronization treatment +quenching and tempering, the lifetime of the whetstones forming die with boronizing is 3.5 times than the old one. Keywords: Boronizing; Whetstone; Forming Die

Abstract: Boride layer was formed on the surface of Cr12MoV after being treated by boronizing technology, and it has high hardness, excellent high temperature oxidation resistance and other characteristics so the boronizing process are widely used in the heat treatment technology of mold and wear-resistant workpiece. But the boronizing technology also has disadvantages such as larger brittleness in the boronizing layer. In order to improve Cr12MoV boriding organizations, it is found that the infiltration of rare earth elements can improve the performance of a single boride layer. In this paper, by changing the temperature, time, rare earth addition and other parameters , the optimization parameter was obtained. and this could make infiltration layer more compact. The results of experiment also showed that the hardness and wear resistance of boride layer are significantly improved.

Abstract: One of the difficulties of the world’s mining industry is how to ensure safe and reliable work of the powered support with large mining height more than 6m. The paper introduces the design and calculation of debris shield of the powered shield support with 6.2M large mining height. In this paper, first mechanical model of powered support with large mining height was established, the mechanical characteristics of powered support was analyzed, and overall design of powered support and general structure of debris shield could be done according to the force calculation.

Abstract: The main failure forms of oilstone forming die is serious wear on the work face, so the key point to extend the use life of die is how to control the wear. In order to improve the hardness and resistance to wear and prolong the use life of the oilstone forming die, the boronizing technology was used on the work face of the oilstone forming die. There are some of elements such as B、C、Al、Cr、Si　and Fe etc in boronizing layer, all of them change their contents during boronizing. Maximum value of microhardness of boronizing layer appears in subsurface, not in surface, and lows along depth of boronizing layer. The abrasion resistance of boronizing layer comes out maximum after quenching and tempering. After quenching and tempering, the lifetime of the oilstone forming die with boronizing is greatly improved.