Authors: Jing Chen, Shao Xiang Hao, Xun Fan
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.
785
Authors: Jing Chen, Shao Xiang Hao, Xun Fan
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
261
Authors: Dong Wang, Hui Qin Li, Han Yu Zhao
Abstract: In this study, 45 carbon steel was boronized and borosulphurized at 950°C for 2, 3， 4, 5, 6 and 8 h, respectively. The samples were characterized by scanning electron microscopy, optical microscope, microhardness tester and ring-on-block wear tester. It is found that the surface of borosulphurized samples was dense, compact and relatively smooth; Although the boride layers produced by boro- sulphurizing at 950°C showed a lower microhardness value compared with that produced by boronizing, the wear resistance of the borosulphurized carbon steel is higher than that of boronized sample due to formation of FeS phase in the boride layer.
204
Authors: Tu Erxun Si Dike, Adayi Xieeryazidan, Xin Mei Li
Abstract: In this paper studies the effect of the temperature of boronized layer, holding time and formula of accelerant on the microstructure and properties boronized layer. The result shows that the thickness of boronized layer increases with the increasing of temperature of boronized layer and the holding time expansion. In the experiment, the research contrasts the effect of five groups of boron-sulphurizing rare earths co-cementation and finds that the best effect is to add 1.5% sulfide and 5% rare earth in reagent. The metallographic analysis and hardness testing show that the properties of boronized layer have improved evidently.
217
Authors: Xiao Ming Yuan, Hong Yu Wang, Yu Feng Zhao, Xiao Jing Xu, Man Cheng
Abstract: In order to improve the surface wear-resistance and overall shock-resistance of 65Mn steel, effects of rare earth (RE) particle size, adding amount and boronizing time subjected to quenching and medium-temperature tempering treatment were studied systematically. Optimizing basic component of low-temperature boronizing reagent and RE types, the depth of boronizing layer was selected as main evaluation parameter through the orthogonal test of RE-boronizing. Experimental results show that, cerium oxide with particle size of 20nm and content of 4% has the best effect of accelerating boronizing process on 65Mn steel at 700°C for 9 h, and the depth of boronizing layer with RE-boronizing is about 3.3 times than without adding RE; meanwhile, the heart of 65Mn steel still keeps good strength and toughness due to temper troostite microstructure. It can be concluded that the strengthening and toughening treatment of low-temperature RE-boronizing can obtain hard-surface and tough-core properties on 65Mn steel.
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