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以锡青铜QSn7-0.2合金为研究对象,通过进行金相、硬度、拉伸、XRD、扫描电镜等实验方法来研究不同的加热温度对挤压成形后的锡青铜组织性能的影响。结果表明:加热至720℃挤压后坯料的组织性能最佳,尤其是断面收缩率,从而为下一步旋压工艺提供最佳的毛坯;并对加热至780℃挤压开裂的原因进行分析发现:加热至780℃时,坯料表面边部有“锡汗”冒出,随后挤压成形的杯形件端面在“锡汗”区域产生裂纹,对其组织进行分析发现,此区域显微组织呈铸态树枝晶,晶内偏析明显,并发现三元共晶组织(α+δ+Cu_3P),三元共晶体的存在引起合金的热脆,这是锡青铜杯形件热挤压时产生裂纹的主要原因。
With tin bronze QSn7-0.2 alloy as the research object, the effect of different heating temperature on the microstructure and properties of tin bronze after extrusion was studied by means of metallographic examination, hardness test, tensile test, XRD and SEM. The results show that the microstructure and properties of the billet after being heated to 720 ℃ are the best, especially the reduction of area, so as to provide the best blank for the next spinning process. The analysis of the reasons of extrusion cracking at 780 ℃ : Heated to 780 ℃, the blank surface edge of the “tin sweat ” emerge, then the extrusion of the cup-shaped end face in the “Sikhan ” area crack, the organization analysis found that this area Microstructure was as-cast dendrites with obvious intragranular segregation. It was found that the existence of ternary eutectic (α + δ + Cu_3P) and ternary eutectic caused hot embrittlement of the alloy, which is the hot extrusion of tin bronze cup The main reason for cracking when pressed.