齿圈的粉末热锻加工工艺

机床行业中钻夹头是大量应用的机床附件,其上的齿圈是主要的受力零件,该工件原是采用机加工方法进行加工,不仅费工、费时,而且还浪费材料,现在已逐渐为冷压工艺所取代。图1和图2所示分别为典型的零件图和冷挤压毛坯图。

基于数字式铜加工热锻红冲生产线的方案设计

针对水暖制造行业对数字式自动化制造的迫切需求,从提高加工自动化入手,通过采用自动切割料、中频加热、机械手自动上下料和模具自动喷润滑油装置、红料温度检测、数据采集与分析、控制系统及生产管控软件几方面技术的开发应用,研制出数字式铜加工热锻红冲柔性生产线。从而实现数据采集分析生产效率、设备利用率、故障情况分析、设备OEE、能耗、工人的劳动生产率以及工资结算等,为今后实现数字化工厂奠定了基础。

Material driven workability simulation by FEM including 3D processing maps for magnesium alloy

The three-dimensional （3D） processing maps considering strain based on the two-dimensional （2D） processing maps proposed by PRASAD can describe the distribution of the efficiency of power dissipation and flow instability regions at various temperatures, strain rates and strains, which exhibit intrinsic workability related to material itself. Finite element （FE） simulation can obtain the distribution of strain, strain rate, temperature and die filling status, which indicates state-of-stress （SOS） workability decided by die shape and different processing conditions. On the basis of this, a new material driven analysis method for hot deformation was put forward by the combination of FE simulation with 3D processing maps, which can demonstrate material workability of the entire hot deformation process including SOS workability and intrinsic workability. The hot forging process for hard-to-work metal magnesium alloy was studied, and the 3D thermomechanical FE simulation including 3D processing maps of complex hot forging spur bevel gear was first conducted. The hot forging experiments were carried out. The results show that the new method is reasonable and suitable to determine the aoorooriate nrocess narameters.

不锈钢园形吊环螺母(或螺栓)裂纹产生原因分析

使用宏观分析和金相手段分析了吊环螺母(或螺栓)产生裂纹的原因,并提出了加工上的改进意见。

Mechanical characterization of cp-Ti produced by investment casting

The influence of hot swaging（SW） and annealing treatment on microstructure and mechanical properties of commercially pure titanium produced by investment casting was evaluated.The as-cast samples showed a typical microstructure consisting of a variety of α-morphologies,while the hot swaged samples exhibited a kinked lamellar microstructure.Annealing at 500 °C did not significantly change this microstructure while annealing at 700 and 870 °C led to recrystallization and formation of equiaxed microstructures.The cast bars exhibited a typical hard α-layer in near-surface regions with a maximum depth and maximum hardness of 720 μm and HV0.5 660,respectively.Due to SW,the tensile strength of the as-cast material drastically increased from 605 MPa to 895 MPa.Annealing at 500 °C decreased the tensile strength slightly from 895 to 865 MPa while annealing at 700 °C led to a further pronounced drop in tensile strength from 865 to 710 MPa.No additional decrease in tensile strength was noticed with increasing the annealing temperature from 700 to 870 °C.The true fracture strain of the as-cast and hot swaged samples was in the range of 0.05 to 0.12,while the annealed samples showed values in the range of 0.25 to 0.53.In addition,the as-cast and hot swaged samples revealed a brittle cleavage fracture surfaces.However,the annealed samples showed a transgranular ductile fracture with formation of dimples.

Hot forging of Mg-4Al-2Ba-2Ca(ABa X422) alloy and validation of processing map

A cup-shaped component of Mg-4 Al-2 Ba-2 Ca（ABa X422） alloy was forged in the temperature range of 300-500 °C and at speeds in the range of 0.01-10 mm/s with a view to validate the processing map and study the microstructural development. The process was simulated through finite-element method to estimate the local and average strain rate ranges in the forging envelope. The processing map exhibited two domains in the following ranges：（1） 300-390 °C and 0.0003-0.001 s^-1, and（2） 400-500 °C and 0.0003-0.3 s^-1 and both represented dynamic recrystallization（DRX）. The map revealed a wide flow instability regime at higher strain rates and temperatures lower than 400 °C, in which flow localization occurred. Forgings produced under conditions of the above two domains were sound and symmetrical, and had finer grain sizes when being forged in the first domain. However, when being forged in the flow instability regimes, the alloy fractured before the final shape was reached. The experimental load-stroke curves for the conditions within the domains correlated well with the simulated ones, whereas the curves obtained in the instability regime were uneven.

发动机阀门

①部件所需必要性能发动机阀门（以下简称阀门）的作用是从活塞的吸入侧吸入燃料和空气，然后从活塞的排出侧将燃烧气体排出。阀门与活塞连动进行着高速往复运动，起着活塞内气体开闭阀的作用。阀门在往复运动的时候，阀门伞部的外周面因与活塞顶侧接触，所以要求有高的耐磨性（高温硬度），另外因为从伞到轴的头部要承受重复载荷，所以需要有必要的疲劳强度，同时也要求具有耐氧化和耐高温腐蚀性。