热加工工艺对医用TC4合金棒材显微组织的影响

摘要

研究了热加工工艺对医用TC4合金大规格棒材显微组织的影响.研究结果表明:采用单一的拔长变形方式或单一的镦拔变形方式,不能全面解决医用TC4合金大规格棒材生产过程中经常出现的显微组织不均匀和成品率低下等问题；采用温度梯度镦拔组合变形工艺(Tβ+ (30 -70)℃镦拔,变形量50％→Yβ-(10 - 30)℃镦拔,变形量50％→Tβ- (30 ～70)℃镦拔,变形量50％),可以有效改善精锻用原始棒坯的组织,从而获得具有均匀细小等轴组织的医用TC4合金(φ)70 mm棒材.%The effect of thermal processing on microstructure of large size medical TC4 alloy bars was investigated. The results show that the problem like uneven microstructure and low finished products rate cannot be totally resolved only by the process of single stretching deformation mode or single upsetting - stretching deformation. The novel process of temperature gradient upsetting - stretching deformation: ( Tβ + (30 ~ 70 ) °C upsetting - stretching, deformation 50%→Tβ-(10～30) °C upsetting- stretching, deformation 50%→Tβ-(30 ~ 70)℃ upsetting -stretching, deformation 50% ) , can greatly improve the structure of original bar billet and finally get medical TC4 alloy precise forging bar in diameterΦ70 mm , and with better microstructure.