共查询到18条相似文献,搜索用时 109 毫秒
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车轴倒棱滚圆过程中,合理的砧型结构对于保证锻件质量有重要作用。本文以DEFORM软件为平台,分别利用圆弧砧、平砧两种砧型对方坯倒棱滚圆进行三维数值模拟,比较两种砧型下火车轴倒棱滚圆成形后的尺寸精度和锻件内部应力应变状态;模拟结果表明:圆弧砧倒棱过程中,压下率大于10%后,心部压应力逐渐增大,平砧心部拉应力一直存在;滚圆结束后采用圆弧砧的锻件心部等效应变大于平砧33.3%;从滚圆精度方面分析,圆弧砧滚圆后圆周上测试点方差小于平砧测试点方差,并且平砧滚圆后的锻件平均直径大于理想值1%。说明圆弧砧倒棱滚圆可以得到成形质量和力学性能、精度最佳的火车轴。 相似文献
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在钛合金长方体锻件的锻造中,倒棱滚圆长方体锻件是最后一道成形工序,也是整个锻造工艺过程中非常重要一道工序。利用Dform软件,研究钛合金长方体锻件的倒棱滚圆过程,不同的砧形对锻件尺寸精度及其内部应力、应变大小分布的影响。 相似文献
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水平V型砧锻造法,可以通过控制锻件金属的流动方向减少轴类锻件力学性能的异向性,在锻件内部应力状态、金属纤维组织、锻件的整体性能、宏观几何形状等方面都优于普通平砧锻造法。采用有限元分析方法,对水平V型砧锻造法进行了数值模拟,结果显示,采用水平V型砧锻造法时,在砧宽比为1.0和料宽比为0.5的条件下,锻件心部的横向应力都处于压应力状态,而采用普通平砧锻造法使用相同工艺参数时,则会出现不利的拉应力状态。这表明水平V型砧锻造法比普通平砧锻造法在控制轴类锻件的横向应力上更有利,有更广泛的工艺参数范围。 相似文献
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轴类大锻件拔长可以采用V型砧、四砧径向锻造等。为了解这些拔长方式对锻件芯部变形的影响,应用有限元软件Super Form模拟了拔长锻造过程,对比分析了V型砧和四砧径向锻造两种工艺方法的锻透性。研究表明:V型砧拔长,锻后锻件内部等效应变分布不均匀,各处变形差异较大,经3道次拔长后,锻件芯部锻透性较好,给定条件下的累积等效应变约为1.6;四砧径向锻造,锻后锻件内部等效应变分布比较均匀,但锻件芯部锻透性较差,给定条件下芯部等效应变小于0.2,且端部一定长度范围内,芯部等效应变更小,经4道次拔长后,芯部累积等效应变为0.8左右。 相似文献
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采用120°角度尺等简单自制工辅具,实现了对曲拐空间相位角度和偏心量的控制,减少三拐曲轴工艺重量、降低材料成本,成功整体锻造了隔膜泵三拐曲轴,实现了自由锻无错移大偏心曲拐成形,降低了加工周期,外形尺寸及内部质量均符合技术要求。 相似文献
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针对120°42CrMo齿条的形状特点制定了最后用弯曲工序成形的锻造工艺。生产实践证明,与传统工艺相比,用此种工艺方案生产的齿条内部质量好,原料成本投入少。 相似文献
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结合实际镦粗变形工艺,把镦粗变形划分为三个阶段或状态,即锻透、压实、焊合。指出空洞压实后的形态或痕迹与空洞的形态、大小,空洞与主拉形变方向有关。坯料镦粗时仅仅考虑整体锻比是不够的,还必须注意单次压下量。并介绍了一种既能压实焊合空洞类缺陷,又能改善夹杂物分布的新型V型板镦粗工艺。 相似文献
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Workability domain without the onset of flow instability was developed by numerical simulation and response surface method(RSM) for complex-shaped straight spur gear forging. The processing map of AZ31 B alloys was calculated from flow stress curves and then integrated with the finite element model to simulate the distribution of flow instability in the straight spur gear undergoing isothermal forging process. Occurrence of flow instability depends on forging temperature, punch velocity and billet reduction. Taking forging temperature and punch velocity as design variables, while billet reduction as response variable, RSM of workability domain was established. Analysis of variance indicates that forging temperature is the most significant factor determining the appearance of flow instability in the forged gear. Flow instability is easier to take place at lower temperatures of 250 and 300 °C in the early stage of forging but at higher temperatures of 350 and 400 °C in the later stage of forging, which is attributed to different deformation mechanisms and dynamic recrystallization behaviors at different temperatures or deformation levels. Meanwhile, increasing punch velocity further reduces the workability of the forged gear.Four different processing paths were chosen to carry out the gear forging trials. Visual observations and metallographic examinations demonstrate that the developed workability domain contributes to optimization of forging parameters. 相似文献
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Flashless precision forging of a two-cylinder-crankshaft 总被引:1,自引:0,他引:1
Flashless precision forging is a special process of drop forging performed in closed dies. This process is distinguished by high quality and the ability to achieve a near net-shape part. Latest research results have shown that it is possible to forge a two-cylinder crankshaft without flash. This was realized using a multi-directional forging tool and a flashless precision forging operation. A new method for a three dimensional shrinking compensation facilitates the construction process. 相似文献
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研究了采用300 mm厚连铸坯锻轧生产核电特厚钢板的工艺,通过对连铸坯直轧、模铸和连铸坯锻轧3种不同工艺生产的核电特厚钢板内部质量和力学性能进行对比分析,结果表明:连铸坯直轧工艺生产的特厚钢板不能满足NB/T47013-2015《承压设备无损检测》Ⅰ级和GB/T 5313《厚度方向性能钢板》Z向断面收缩率大于35%的要求,钢板内部存在裂纹和偏析。采用锻轧工艺生产的钢板能够100%满足探伤要求,连铸坯芯部裂纹和柱状晶在高温锻造过程中能够有效焊合和破碎,并且高温加热过程对连铸坯的芯部偏析有很大程度的改善,通过锻造和轧制工艺相结合,能够解决连铸坯直轧出现的探伤不合问题,并且能替代高成本的模铸生产,进一步降低生产成本。 相似文献