• CN:11-2187/TH
  • ISSN:0577-6686

机械工程学报 ›› 2018, Vol. 54 ›› Issue (12): 156-164.doi: 10.3901/JME.2018.12.156

• 材料科学与工程 • 上一篇    下一篇

P91厚壁管铸挤复合成形工艺参数对组织和力学性能的影响

惠恬静, 雷步芳, 李永堂, 贾璐   

  1. 太原科技大学金属材料成形理论与技术山西省重点实验室 太原 030024
  • 收稿日期:2017-06-20 修回日期:2017-11-28 出版日期:2018-06-20 发布日期:2018-06-20
  • 通讯作者: 李永堂(通信作者),男,1957年出生,博士,教授,博士研究生导师。主要研究方向为锻压设备、材料先进制造技术。E-mail:liyongtang@tyust.edu.cn
  • 作者简介:惠恬静,男,1991年出生。主要研究方向为大口径厚壁管热挤压技术。E-mail:2398998891@qq.com
  • 基金资助:
    国家自然科学基金(51675361)、山西省回国留学人员科研(2015-086)和山西省重点学科建设经费资助和校研究生科技创新(2016XC10)资助项目。

Effects of Processing Parameters of Casting-extruding on Microstructure and Mechanical Properties of P91 Thick-wall Steel Tube

HUI Tianjing, LEI Bufang, LI Yongtang, JIA Lu   

  1. Shanxi Key Laboratory of Metallic Materials Forming Theory and Technology, Taiyuan University of Science and Technology, Taiyuan 030024
  • Received:2017-06-20 Revised:2017-11-28 Online:2018-06-20 Published:2018-06-20

摘要: 铸挤复合成形工艺是生产大口径厚壁管的新型成形技术,与传统工艺相比,具有工艺流程短、节能节材等优点。以铸态T/P91耐热合金钢为研究对象,通过高温压缩试验和金相组织分析,建立铸态合金钢的本构模型和组织演变机理;利用虚拟正交试验,分析不同工艺参数对厚壁管平均晶粒尺寸、组织均匀性及其最大挤压力的影响主次顺序;借助于理论分析与有限元模拟,研究挤压工艺参数对金属变形和组织演变规律的影响;对厚壁管进行热处理,分析热处理前后组织、性能变化。研究结果表明:原始坯料温度(T0)、挤压速度(v)和挤压比(λ)是影响晶粒大小及其均匀性的主要因素,当原始坯料温度为1 250℃、挤压比为7~9、挤压速度为30~50 mm/s时,厚壁管晶粒细小且分布均匀,获得组织、性能优良的厚壁管;热处理前管材组织为针状马氏体+板条状马氏体,热处理后为回火马氏体,强度、硬度明显下降,塑韧性大幅提高。

关键词: 大口径厚壁管, 晶粒分布均匀性, 平均晶粒尺寸, 铸挤复合成形

Abstract: Casting-extruding forming technology is a new technology to produce large caliber-thick-wall steel tube. It possesses many advantages such as short process, saving energy and materials. Taking P91 steel commonly used in thick-wall tube for example, microstructure evolution mechanism and laws during deformation is revealed by means of thermal simulation experiments and microstructure analysis. On the basis of virtual orthogonal test, the effect of different processing parameters on the average grain size, grain uniformity and the maximum extrusion force is obtained. Forming process parameters and their influence on metal deformation and microstructure evolution during extruding forming of cast tube are investigated by theoretical analysis and numerical simulation. The effect of heating treatment parameters on the structure and mechanical property of the material is also studied. The results show that extrusion speed v, initial billet temperature T0 and extrusion ratio λ have more obvious effects on the average grain size and the grain uniformity than other ones. When the initial billet temperature is 1 250℃, the extrusion speed from 30 to 50 mm/s, and the extrusion ratio from 7 to 9, the average grain size is smaller and the grain uniformity is improved. Before heat treatment, the microstructure of the tube is acicular martensite and lath martensite, but after normalizing and tempering, it becomes the tempered martensite. The strength and hardness decrease obviously, while ductility and toughness are improved significantly.

Key words: average grain size, casting-extruding forming, grain uniformity, large caliber thick wall steel tube

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