钛合金铸锭制备全流程数值模拟研究

Study on Numerical Simulation of Whole Process of Titanium Alloy Ingot Production

  • 摘要: 目前工程化钛合金铸锭已形成了“液压机压制电极块+氩气保护等离子弧焊接电极+真空自耗电弧熔炼”的成熟制备流程。但高性能钛合金冶金缺陷偶发,在工程化应用背景下,研究对象的规格放大,制备过程中各因素对成品铸锭质量的影响规律难以通过有限的实验手段量化表征。本研究以TC17钛合金铸锭为研究对象,采用全流程数值模拟和实验相结合的方法,对电极块压制过程中相对密度及等效应力分布、焊接后电极的焊缝形貌及残余应力分布,以及真空自耗电弧熔炼过程中搅拌电流对最大熔池深度和Cr元素分布的影响规律等进行研究。结果表明:压制过程中电极块的相对密度和残余应力分布不均匀,易引起成品铸锭的质量问题;焊接后电极中的残余应力峰值位于焊缝中心及热影响区;真空自耗电弧熔炼过程中,搅拌电流对最大熔池深度和Cr元素分布的影响规律非线性。本研究深入分析TC17钛合金铸锭制备过程中成分均匀性的影响因素和控制措施,为成功制备成分均匀的优质TC17钛合金铸锭及实现低成本工程化目标奠定基础。

     

    Abstract: At present, the engineering titanium alloy ingot has formed a mature production process of using hydraulic press to press electrode block & argon shielding plasma welding electrode & vacuum arc melting method. However, the metallurgical defects of high-performance titanium alloys are sporadic. In the context of engineering application, the specification of the research object is enlarged, and it is difficult to quantify the influences of various factors on the ingots through limited experimental methods. In this paper, TC17 titanium alloy is taken as the research object, and the whole process numerical simulation and experimental analysis are combined to carry out investigate the relative density and equivalent stress distribution of the electrode block in the cause of preparation, weld morphology and residual stress distribution of the electrode welded, and the influences of sti- rring electric current on the maximum depth of the molten pool and Cr distribution in the vacuum arc remelting process. Results show that in the process of pressing, the relative density and residual stress of the electrode block are uneven, which will cause quality problem of the product. The residual stress peaks of the welded electrode occur in the center of beam and the heat affected zone. In the process of vacuum arc remelting, the effect laws of stirring current on the maximum depth of the molten pool and the distribution of Cr element are nonlinear.The influencing factors and control measures of composition uniformity in the production process of TC17 titanium alloy ingot are analyzed in depth, which lays a foundation for realizing the engineering goal of high uniformity, high consistency and low cost of TC17 titanium alloy ingot.

     

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