电化学法处理废硬质合金直接回收金属钴和碳化钨

首次采用电化学法处理废硬质合金直接回收金属钴和碳化钨，工艺简单可靠，具有较好的环境和经济效益。     

车用空调器压缩机前端板铸件壳型铸造工艺实践

对前端板铸件壳型铸造中存在的铸造缺陷,采用优化浇注系统,对铁水进行二次孕育处理,调整碳当量控制在3.90%~4.15%,硅含量降低0.15%~0.20%,使产品抗拉强度≥270MPa,硬度(HB)为187~241,满足用户要求。     

倾斜板角度对亚共晶高铬铸铁半固态组织的影响

采用倾斜板冷却体法对亚共晶高铬铸铁进行半固态成形,研究了倾斜板角度对亚共晶高铬铸铁半固态组织的影响规律。结果表明:倾斜板角度过大或过小都将使得组织中的初生奥氏体较粗大、圆整度较小。当倾斜板角度较小时,金属液的流速相对较慢,枝晶与枝晶和枝晶与金属液间的冲刷、碰撞、剪切作用较小,晶粒易于长大,导致枝晶状初生奥氏体比较多。当倾斜板角度较大时,金属液流速相对较快,金属液在倾斜板上流动的时间相对较短,枝晶间以及枝晶与金属液间的冲刷、碰撞、剪切作用时间相对较短,导致枝晶状初生奥氏体也比较多。当倾斜板角度为45°时,制备的亚共晶高铬铸铁初生奥氏体的尺寸最小,圆整度最高。     

热处理工艺对高速钢轧辊组织和性能的影响

研究了淬火温度、冷却方式、回火温度和回火次数对高速钢轧辊组织和性能的影响。结果表明,空冷的高速钢轧辊淬透性差,油冷的高速钢轧辊易出现裂纹,盐冷的高速钢轧辊具有优良的淬透性,不易出现裂纹,辊面硬度高,硬度均匀性好,耐磨性好。     

残余应力检测技术及其应用

着重叙述了残余应力检测技术,对其中几种典型的测定方法在我厂产品上的应用可能进行了探讨,并对各种测定方法进行了比较。     

真空倾转差压铸造法的应用探讨

将现有的差压铸造机改造成可真空充型倾转加压倒置的差压铸造机 ,它实质是集真空低压铸造、差压铸造、重力铸造的各种优点于一身的新铸造方法 ,它可使铸件的组织更加致密、减少打压渗漏、基本上消除铸件内的气孔及缩孔、大幅度提高材料的强度和韧性     

粉煤灰颗粒增强铝基复合材料的研究

采用粉末冶金法成功制备了煤粉灰颗粒增强铝基复合材料。煤粉灰颗粒大多为球形,密度为2.75g/cm3,颗粒直径主要集中在5～60μm范围内,主要成分为SiO2、Al2O3和Fe2O3,三者质量分数总和超过85%。经SEM分析表明,该复合材料中存在着颗粒团聚,并有少量气孔产生。随着煤粉灰质量分数的增加,复合材料的密度逐渐减少;当煤粉灰颗粒的质量分数在10%以下时,该复合材料的硬度是上升的,超过10%时硬度开始下降。     

Control of material flow in a combined backward can - forward rod extrusion

The paper deals with an analysis of an extrusion process with a divided material flow. As we are forced to seek for optimal technological solutions with short testing times and low risks and costs, a reliable process evaluation is of the greatest importance.

The paper discusses the influences of tool geometry, friction and lubrication as well as workpiece properties on balanced material flow in a combined extrusion process. The FEM analysis applying the DEFORM code has been used in order to predict the process parameters and to estimate its stability. The subsequent experimental verification has resulted in a conclusion that modern computer aided tools, tuned by proper experimental sets, can be used for fast and reliable cold metal forging process planning.     

A combined DEM–FEM numerical method for Shot Peening parameter optimisation

A numerical modelling approach capable of simulating Shot Peening (SP) processes of industrial interest was developed by combining the Discrete Element Method (DEM) with the Finite Element Method (FEM).In this approach, shot–shot and shot–target interactions as well as the overall shot flow were simulated efficiently using rigid body dynamics. A new algorithm to dynamically adapt the coefficient of restitution (CoR) for repeated impacts of shots on the same spot was implemented in the DEM code to take into account the effect of material hardening. Then, a parametric study was conducted using the Finite Element Method (FEM) to investigate the influence of the SP parameters on the development of residual stresses.Finally, a two-step coupling method is presented to combine the output of DEM simulation with FEM analyses to retrieve the Compressive Residual Stresses (CRS) after multiple impacts with the aim to evaluate the minimum area required to be modelled to realistically capture the field of residual stresses. A series of such coupled analyses were performed to determine the effect of peening angle and the combination of initial velocity and mass flow rate on CRS.