挤压温度对铝合金内螺纹管管壁组织的影响  

Influence of extrusion temperature on wall structure of internal threaded aluminum alloy tube

作　　者：熊振 李旭东 黎华杰 黄东男[1,2] 纪维玥 XIONG Zhen;LI Xudong;LI Huajie;HUANG Dongnan;JI Weiyue(School of Materials Science and Engineering,Inner Mongolia University of Technology,Hohhot 010000,China;Chinalco Materials Application Research Institute Co.,Ltd.,Beijing 102200,China)

机构地区：[1]内蒙古工业大学材料科学与工程学院,呼和浩特010000 [2]中铝材料应用研究院有限公司,北京102200

出　　处：《材料科学与工艺》2022年第4期49-60,共12页Materials Science and Technology

基　　金：国家自然科学基金资助项目(5186050063)。

摘　　要：内螺纹管主要由两部分组成,管壁和内螺纹齿部位,其成形后的质量及换热性能不仅与螺纹齿的质量有关,也与管壁的成形质量有关,并且微观组织的不同也将影响挤压后管材的质量和性能。为成形出高质量的内螺纹管,本文在常用挤压方法的基础上结合金属挤压理论,提出了运用螺纹模芯结合无缝圆管工模具挤压成形铝合金内螺纹管的方法,并利用电子背散射衍射(EBSD)技术分析了挤压温度(420~480℃)对铝合金内螺纹管管壁组织演变的影响。研究表明:在100 mm/min的恒定挤压速度下,随着挤压温度的逐渐升高,管壁横、纵截面的平均晶粒尺寸逐渐增大,分别由420℃的10.5和8.3μm增大至480℃时的18.1和11.6μm;管壁横截面组织主要为周向带状晶,纵截面组织主要为轴向带状晶。对成形后管壁织构的分析表明,随着挤压温度的逐渐升高,管壁变形织构增强,再结晶组织逐渐增多。Internal threaded tubes are mainly composed of two parts: the tube wall and the internal thread teeth. The quality and heat exchange performance of the tube after forming are not only related to the quality of the thread teeth, but also to the forming quality of the tube wall. Besides, the difference in microstructure affects the quality and performance of the tube after extrusion. Therefore, in order to form internal threaded tubes with better quality, it is necessary to study the evolution law of the structure of the tube wall and explore the possible changes in the tube wall. On the basis of the common extrusion method and combined with the theory of metal extrusion, a method of forming internal threaded aluminum alloy tubes was proposed, which uses a threaded die core and a seamless round tube die. The effect of extrusion temperature(420~480 ℃) on the microstructure evolution of the tube wall was analyzed using EBSD technology. Research results show that at a constant extrusion speed(100 mm/min), with the gradual increase in extrusion temperature, the average grain size of the transverse and longitudinal sections of the tube wall gradually increased, from 10.5 and 8.3 μm at 420 ℃ to 18.1 and 11.6 μm at 480 ℃, respectively. The transverse sectional structure of the tube wall was mainly circumferential banded crystals, and the longitudinal sectional structure was mainly axial banded crystals. By analyzing the texture of the tube wall after forming, it was found that with the gradual increase in the extrusion temperature, the deformation texture of the tube wall was enhanced, and the recrystallized structure was gradually increased.

关 键 词：铝合金内螺纹管 挤压温度 管壁横截面 管壁纵截面 组织演变 

分 类 号：TG379[金属学及工艺—金属压力加工]