CAJ | 학술논문

针对环模式秸秆压块机成型模具易磨损的问题，该文对45钢秸秆燃料成型模具的磨损过程进行了研究。通过测试磨损模具的磨损形貌，分析了该类磨损的作用机理，结合分形理论得出了磨损深度率的计算模型，在此基础上探讨了影响磨损的因素，并针对成型速度和模具硬度对磨损的影响进行了有限元仿真和试验验证。结果表明：秸秆原料对金属模具的磨损沿进料方向依次减弱，磨损主要发生在模具中间部位和下侧面，以硬磨料磨损为主；模具磨损受多种因素影响，其中模具硬度越大、成型速度越低，模具耐磨性能越好，硬度影响大于成型速度的影响；成型速度为9 mm/s时，模具耐磨性能和成型产品品质较好，而用于秸秆燃料成型的模具硬度不能太高，否则易发生脆性断裂。该文研究结果有利于指导压块机组合环模的设计。
침대배모식갈간압괴궤성형모구역마손적문제，해문대45강갈간연료성형모구적마손과정진행료연구。통과측시마손모구적마손형모，분석료해류마손적작용궤리，결합분형이론득출료마손심도솔적계산모형，재차기출상탐토료영향마손적인소，병침대성형속도화모구경도대마손적영향진행료유한원방진화시험험증。결과표명：갈간원료대금속모구적마손연진료방향의차감약，마손주요발생재모구중간부위화하측면，이경마료마손위주；모구마손수다충인소영향，기중모구경도월대、성형속도월저，모구내마성능월호，경도영향대우성형속도적영향；성형속도위9 mm/s시，모구내마성능화성형산품품질교호，이용우갈간연료성형적모구경도불능태고，부칙역발생취성단렬。해문연구결과유리우지도압괴궤조합배모적설계。
As one of the important biomass resources in China, straw plays an important role in energy utilization. While straw solidifying technology provides an effective utilization route which has been widely used. After densification, both density and intensity of the straw fuel were improved, making it easier to transport, store and use. And this efficient utilization is also crucial for providing bio-energy, releasing the risk of environmental pollution caused by crop straw burning. But there are still some problems, such as easy wear of ring die, which will shorten its service life. In this paper, the wear behavior of ring die has been studied based on experimental test and theoretical analysis. After the shape of the worn ring die was tested, the microscopy morphology was obtained by scanning electron microscopy (SEM), and then the wear mechanism was analyzed. By testing it is found that abrasion mainly occurs in the middle part and lower side of the die, and abrasion gradually weakens along the feed direction. Hard abrasive wear plays a leading role in the wear process;the material loss of the die surface is caused by the cutting fracture mechanism. According to conclusions above, the calculation model of this abrasive wear was deduced based on fractal theory. It shows that the wear rate of the ring die is related to the particle size silhouette coefficient G, contact area Ar, forming speed v and material properties. Then the effect of the forming speed and the hardness of the ring die to this abrasive wear was investigated by using finite element analysis software DEFORM. The forming speed was set as 7, 8, 9 and 10 mm/s four levels, and the die hardness was set as 42.5, 45, 47.5 and 50 HRC four levels. The forming temperature was 110℃ while the extruded material length was 45 mm. Simulation results show that the wear depth of the ring die increases with increasing forming speed and decreases with increasing die hardness. Range analysis results of the above two factors are RHRC=2.846, RV=1.822, RHRC>RV, which means that die hardness plays a more important role than forming speed to the die wear. To verify these conclusions, 45 steel dies were divided into four groups for heat treatment to obtain different hardness (36.2 HRC, 42.8 HRC, 47.9 HRC and 52.6 HRC). The heat treatment method was tempering after whole quenching, different hardness was achieved by controlling the tempering temperature. Then these ring dies were installed into the machine for production testing after being weighed and the forming speed was set as 9 mm/s. The experiment results indicate that the wear resistance of the ring die increases with increasing hardness, while the die hardness is between 36.2 and 47.9 HRC. Because it is more difficult for the abrasive to press into the metal with a higher die hardness. Its brittleness will be enhanced if the surface hardness is too high for the same material, this may lead to die failure directly under the high pressure working environment. The die with a hardness of 52.6 HRC was broken shortly after the experimental test started. While the forming speed is 9 mm/s, the interior of the fuel combines relatively close, and the product density is 0.96 g/cm3 with a better ignition performance. In addition, the fractal dimension of the worn working surface decreases with increasing die hardness.