多道次连续挤压对铜组织和性能的影响

The Influence of Multi-pass Continuous Extrusion on the Microstructure and Properties of Copper

连续挤压技术是一种高效率、节能和成本低廉的绿色塑性成型的方法,其最大特点就是利用了摩擦力作为驱动力和热源,大大减低了生产成本。选择Φ8 mm纯铜进行多道次重复连续挤压,实验设备型号为TLJ250连续挤压机,挤压轮转速选取为6 r/min。实验结束后,分别对经1~3道次连续挤压后的铜产品进行拉伸试验、硬度试验以及金相组织的观察。经过多道次连续挤压后,纯铜粗大晶粒都发生了不同程度的破碎,形成数量众多且等轴细小的均匀晶粒。第2道次延伸率较第1道次提升4.6%,第3道次较第1道次提升4.9%。但是,第2道次的抗拉强度比第1道次降低12.96 MPa,第3道次比第1道次的抗拉强度降低11.65 MPa。纯铜产品的硬度值经过多道次连续挤压后,略有增加。

Continuous extrusion technology is a high-efficiency,energy-saving,and low-cost green plastic forming method.Its biggest feature is the use of friction as the driving force and heat source,greatly reducing production costs.Select pure copper for multi pass repeated continuous extrusion,experimental equipment model is TLJ250 continuous extrusion machine,extrusion wheel speed is selected as 6 r/min,Φ8 mm.After the experiment,tensile tests,hardness tests,and metallographic observations were conducted on the copper products after 1-3 consecutive passes of extrusion.After multiple passes of continuous extrusion,the coarse grains of pure copper undergo varying degrees of fragmentation,forming numerous and equiaxed fine uniform grains.The elongation of the second pass increased by 4.6% compared to the first pass,and the third pass increased by 4.9% compared to the first pass.However,the tensile strength of the second pass decreased by 12.96 MPa compared to the first pass,and the tensile strength of the third pass decreased by 11.65 MPa compared to the first pass.The hardness value of pure copper products slightly increases after multiple passes of continuous extrusion.