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The key manufacturing technologies associated with composition,microstructure,mechanical properties,casting quality and key process control for large martensitic stainless steel castings are involved in this paper.The achievements fully satisfied the technical requirements of the large 700 MW stainless steel hydraulic turbine runner for the Three Gorges Hydropower Station,and become the major technical support for the design and manufacture of the largest 700 MW hydraulic turbine generator unit in the world developed through our own efforts.The characteristics of a new high yield to tensile strength (Rp0 2/Rm) ratio and high obdurability martensitic stainless steel with ultra low carbon and high cleanliness are also described.Over the next ten years,the large martensitic stainless steel castings and advanced manufacturing technologies will see a huge demand in clean energy industry such as nuclear power,hydraulic power at home and abroad.Therefore,the new high yield o tensile strength (Rp0.2/Rm) ratio and high obdurability martensitic stainless steel materials,the fast and flexible manufacturing technologies of large size castings,and new environment friendly sustainable process will face new challenges and opportunities. 相似文献
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1. IntroductionESRC is a special working method gathering refiningand casting of molten metal together. With its specialprocess, ESRC can counteract the weakness of commonsand castings, thus get high grade castings with goodinternal quality. In this project, a lot of research has beendone about key technologies of material, process andequipment, which are involved in making guide vane ofhydraulic turbine by ESRC, and the achievements havebeen used in practice.2. Material research2.1 Trial… 相似文献
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近年来,我国大型铸锻件行业技术水平有了较高的提升,但是整体技术水平还相当于上世纪90年代的国际水平,比较落后,面对我国对大量形状复杂、技术含量高、材料性能特殊的大型铸锻件日益迫切的需求,我国大型铸锻件行业应依托装备制造业调整振兴规划,坚持国产化道路,分享我国工业发展的巨大成果。 相似文献
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When heavy machines and large scaled receiver system of communication equipment are manufactured, it always needs to produce large- sized steel castings, aluminum castings and etc. Some defects of hot cracking by thermal stress often appear during solidification process as these castings are produced, which results in failure of castings.Therefore predicting the effects of technological parameters for production of castings on the thermal stress during solidification process becomes an important means. In this paper, the mathematical models have been established and numerical calculation of temperature fields by using finite difference method (FDM) and then thermal stress fields by using finite element method (FEM) during solidification process of castings have been carried out. The technological parameters of production have been optimized by the results of calculation and the defects of hot cracking have been eliminated. Modeling and simulation of 3D thermal stress during solidification processes of large-sized castings provided a scientific basis, which promoted further development of advanced manufacturing technique. 相似文献
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During heat treatment process, the distortion behavior inevitably appears in hydraulic turbine blade castings. In this research, a technology was developed for real-time measurement of the distortion in hydraulic turbine blade castings at the still air cooling and forced air cooling stages during heat treatment process. The method was used to measure the distortion behavior at the cooling stages in both normalizing and tempering processes. At the normalization, the distortion at the blade corner near outlet side undergoes four stages with alternating bending along positive and negative directions. At the tempering stage, the distortion could be divided into two steps. The temperature difference between the two surfaces of blade casting was employed to analyze the distortion mechanism. The measured results could be applied to guide the production, and the machining allowance could be reduced by controlling the distortion behavior. 相似文献
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本文研究了铸件和铸型的热物性值对铸钢件凝固过程温度场数值模拟精度的影响,指出铸型的热物性值较铸件的热物性值对模拟计算精度的影响更大。计算时,必须正确掌握不同铸造工艺条件下确切的热物性值。 相似文献
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铸件充型数值模拟的研究进展 总被引:3,自引:0,他引:3
铸造过程计算机数值模拟技术是当今材料科学的重要前沿领域。本文从铸件充型数值模拟的发展过程、软件的开发状况、计算方法及验证方法等四个方面介绍了国内外铸件充型过程计算机数值模拟的概况。 相似文献
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为保证大型铝合金铸件的质量,通过水力模拟和数值模拟两个途径优化铸造工艺;水力模拟依据相似理论,建立水力模型,选出最佳浇注系统,防止吸气、浇不足等缺陷;数值模拟通过计算铸件动态温度场,来预测缩孔、缩松等缺陷,据此来改变冒口、冷铁的尺寸及数量,控制铸件凝固顺序,保证铸件内部质量,最后,综合水力模拟和数值模拟结果。确定了合理的工艺方案,确保铸件一次浇注成功。 相似文献
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介绍清华大学开发的计算机三维数值凝固模拟软件FT—Star的功能及其在二重集团公司的工艺性试验和应用研究。解决了软件实际应用于铸钢件凝固过程中出现的一些问题,摸索出一些计算经验和规律。对不同铸钢件如何恰当地剖分网格、确定缩孔缩松判据参数、优化补贴工艺设计等都进行了深入研究,保证了计算机数值模拟结果的精确、可靠。实现了铸造缩孔缩松缺陷的预测,避免过去靠经验来进行铸造工艺设计,使工艺设计更具有科学性,大大降低了铸造生产成本。 相似文献