摘要
轴承套圈、法兰等环形零件作为关键连接、传动、回转和支承结构件,在航空航天、风力发电、高铁、船舶和高档数控机床等重大装备制造领域应用非常广泛。环形零件的生产是一种高能耗的热加工过程,传统生产工艺主要有两种:(1)厚板轧制—弯卷—焊接成形,该工艺下环件焊接部位应力集中明显,在高压、强腐蚀等恶劣服役条件下为弱性能区;(2)通过冶炼—浇铸—加热—锭坯开坯—下料—圆棒加热—锻造—冲孔—加热—环坯热辗扩来实现环件生产,该工艺流程冗长,开坯、锻造和冲孔工序设备资金投入巨大,多次加热导致能源消耗和材料浪费严重,不利于环境友好型生产。环件热辗扩过程中的传热-变形-组织演变耦合行为使得环坯经历了多场、多因素作用下多道次、连续局部加载与卸载、不均匀变形和微观组织复杂演变历程,对成形环件的外形尺寸、组织和力学性能均产生显著影响。随着环件应用向着大型、轻量、重载和长寿命方面逐步发展,对其高性能、精确成形与低成本制造提出了更高要求。近年来得到重点研究并取得长足发展的环形零件短流程铸辗复合成形技术以砂型铸造或离心铸造获得的环形铸坯加热后直接进行辗扩为基础,省去了开坯、锻造和冲孔,只需要一次加热,具有工艺流程短和节能节材等突出优点(节材30%以上、节能60%以上),是风电法兰、石油化工容器和高档数控机床主轴承等重大装备高效、高性能和绿色制造的必然要求。然而,在热辗扩过程中不仅要实现环形铸坯截面轮廓达到所要求环件外形尺寸,同时其组织与性能也要得到充分改善和提高,使得对热辗扩过程中组织演变和性能控制面临诸多技术挑战。研究者们深入分析了环形铸坯材料单道次和双道次热压缩变形行为、组织演变规律及其模型构建方法,建立了关于材料常数考虑应变补偿的本构关系模型,为此研究了热-力-组织演变多场耦合及其基于晶粒拓扑变形技术和介观-微观元胞自动机跨层次耦合条件下的热辗扩数值模拟技术,构建了考虑晶粒空间重叠的CA模型,基于工业性试验从织构视角研究了其在铸坯环件热辗扩成形中微观组织和性能控制规律,获得了环件不同区域的晶粒细化极限,可以实现环件短流程铸辗复合成形生产。本文综述了基于锻态环坯和铸态环坯的热辗扩成形技术研究进展,探讨了环形铸坯热辗扩过程中组织与性能协同调控的理论与方法,建立了环形铸坯凝固过程裂纹萌生判据与裂纹控制的工艺方法,提出了环形铸坯热辗扩成形技术的研究发展方向,阐述了双金属复合环形铸坯热辗扩成形技术的研究内容及重点,以期推动环件短流程制造全过程“形”/“性”一体化调控理论与技术发展。
Ring-shape parts such as bearing and flange as the key connect piece,driving medium,rotating member and supporting structure are widely used in major equipment industrial including aerospace,wind power,high-speed rail,ship and high-end numerically-controlled machine.The production in rings is an energy-extensive consumption process.The current technique for ring production mainly includes two kinds:ⅰ)thick plate rolling,bending and welding.The significant stress concentration is presented in the welding areas,which leads to the weak properties in the poor service conditions with high-pressure and corrosion.ⅱ)smelting,ingot pouring,heating,casting,heating,cogging,cutting,rod heating,forging,punching,heating and hot ring rolling.The process is lengthly and the cost of equipments in cogging,forging and punching is huge.The serious energy-consumption and materials wasting in the current process go against environmentally friendly production because of repeatedly heating.The coupling behavior of heat transfer-deformation-microstructure in hot ring rolling results in a complex development of multi-pass,continuous locality loading and unloading,uneven deformation and microstructural evolution with the function of multi-fields and factors.And the geometrical dimensions,microstructure and mechanical properties of the ring blank are significantly affected.As the application of rings develops to large-scale,light-weight,heavy-load and long-life,the demand for manufacturing in high-performance,precision and low cost are proposed.In recent years,the compact cast-rolling compound technique is studied in detail and useful results are obtained.In this process,the ring blank produced by sand casting or centrifugal casting is directly hot rolled.The cogging,forging and punching are leaved and only one heating is needed.Moreover,some advantages of short technological process and materials(above 30%)and energy-conservation(above 60%)are presented.Therefore,the compact process is the inevitable requirement of high-efficiency,high-performance and green manufacturing in the wind power flanges,the petrochemical pressure vessel and numerically-controlled machine base bearing.However,in the hot ring rolling,not only the geometrical dimension of the casting ring blank need to be obtained,but its microstructure and mechanical properties need to be improved and enhanced.A lot of technical challenges occur in the microstructure evolution and performance control of hot ring rolling.Analysis of single-and double-pass compression behavior of casting ring blank,the microstructure evolution rule and its modeling are conducted by researchers.The material constants in the constitutive models considering strain-compensation are established.Furthermore,the simulation of hot rolling with multi-fields coupling of heat transfer-deformation-microstructure,and cross-level coupling of grain topological and mesoscopic-microscopic cellular automaton(CA)are stu-died respectively in detail.The CA models considering grain space overlap is constructed.According to industrial tests,the textural development is introduced to study the control rule of microstructure and mechanical properties in hot rolling of casting ring blank.The grain refinement limitation in different areas of the hot rolled ring is obtained.The results contribute to the achievement of compact cast-rolling compound forming of rings.The research progress on the hot rolling of as-forged ring blank and casting ring blank are summarized.The theories and methods on the integrated control of microstructure and mechanical properties of casting ring blank during the hot rolling are discussed.The crack initiation criterion and processing parameter control on the solidification of casting ring blank are established.The research trends on the hot rolling of the casting ring blank are proposed.The contents and key points in the hot rolling of duplex-metallic casting ring blank are elaborated.This study will promote the development of theory and technique on the integrated control of forming and modification in the compact cast-rolling compound manufacturing of ring parts.
作者
秦芳诚
齐会萍
李永堂
武永红
亓海全
刘崇宇
QIN Fangcheng;QI Huiping;LI Yongtang;WU Yonghong;QI Haiquan;LIU Chongyu(College of Materials Science and Engineering,Guilin University of Technology,Guilin 541004,China;Shanxi Key Laboratory of Metallic Materials Forming Theory and Technology,Taiyuan University of Science and Technology,Taiyuan 030024,China)
出处
《材料导报》
EI
CAS
CSCD
北大核心
2020年第19期19152-19165,共14页
Materials Reports
基金
国家自然科学基金(51875383,51575371)
广西自然科学基金项目(2019GXNSFAA245051,2018GXNSFBA281056)
广西科技重大专项(2018AA23004,GKAA17202007)
桂林理工大学科研启动基金(GUTQDJJ2017140)。
关键词
环形铸坯
热辗扩
织构演变
裂纹控制
双金属环件
as-cast ring blank
hot ring rolling
texture evolution
crack control
duplex-metallic rings
