耐热合金21-4N楔横轧成形的高温损伤机制与控制研究

项目名称： 耐热合金21-4N楔横轧成形的高温损伤机制与控制研究

项目编号： No.51505026

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 机械、仪表工业

项目作者： 郑振华

作者单位： 北京科技大学

项目金额： 20万元

中文摘要： 耐热合金21-4N是一种典型的气门用钢，热强性好，但热塑性差、热变形温度范围窄，在楔横轧成形中容易出现心部疏松,制约了楔横轧气门精密成形工艺的应用。如何定量地预测21-4N楔横轧成形的高温损伤并有效控制缺陷产生已成为亟待解决的关键基础问题。本项目拟结合21-4N成形的微观结构变化和楔横轧变形特征，揭示21-4N楔横轧成形的损伤机制，建立热-力-损伤耦合模型，制定21-4N楔横轧的损伤判定标准；编制有限元用户子程序，建立21-4N楔横轧高温损伤的有限元预测平台；阐明各工艺参数对21-4N楔横轧成形中的损伤形核与演变的独立及耦合影响机制，提出21-4N楔横轧成形的高温损伤控制方法和工艺参数选择方法。研究成果对楔横轧耐热合金的质量控制和模具参数优化具有重要的实用价值，研究方法对楔横轧工艺的损伤预测具有重要的科学意义。

中文关键词： 楔横轧；轧制机理；耐热合金钢；损伤预测；工艺参数

英文摘要： Heat resistant alloy 21-4N is a kind of typical steels used in valve. It possesses good thermal strength, but internal failure easily occurs during cross wedge rolling due to its poor thermo-plasticity and narrow hot deformation temperature range, which has restricted the application of cross wedge rolling in valve precision forming process. So, quantitative prediction and effective control of damage in 21-4N forming during cross wedge rolling are becoming key problems to be solved. This project considers both the evolution of microstructure and deformation characteristics of cross wedge rolling, studies the damage mechanism of 21-4N forming by cross wedge rolling, then models a coupled constitutive equations for heat-transfer, deformation and damage and establishes a proper damage criteria for heat resistant alloy 21-4N forming in cross wedge rolling. User-defined subroutine is going to be programmed, and then we get a new damage prediction method of FEM in cross wedge rolling of heat resistant alloy 21-4N. Based on FEM, damage nucleation and evolution affected by technological parameters variation in cross wedge rolling of heat resistant alloy 21-4N will be studied, and we will provide a new method for damage control and parameters selection. The achievements of this project will have an important practical value of quality control and die parameters optimization in cross wedge rolling of heat resistant alloy. This study also has a great scientific significance in presenting a new research method for damage prediction in cross wedge rolling.

英文关键词： cross wedge rolling;rolling mechanism;heat resistant alloy;damage prediction;technological parameters