锻压技术

加热温度对锡青铜挤压成形后组织性能的影响

英文标题：Effect of heating temperature on microstructure and mechanical properties for tin bronze after extrusion

作者：苏晓波冯再新高超平郝伟岑

单位：中北大学

分类号：TG113

出版年,卷(期):页码：2017,42(2):156-159

摘要：

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+Cu3P），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。

For the tin bronze alloy QSn7-0.2, the influences of different heating temperatures on microstructures and properties through the extrusion were studied by metallography, hardness, tensile, XRD, SEM of experimental methods. The results show that the microstructures and properties of blank through the extrusion are the best at 720 ℃, especially for the reduction of the cross section, which provides the best blank for the next spinning process. Then, the causes of extrusion cracking at 780 ℃ were analyzed. When the temperature is up to 780 ℃, the “tin sweat”emerges at the edge of blank surface, and the cracking occurs in the “ tin sweat ” zone on the end surface of the extruded cup. Furthermore, based on microstructure analysis, the cast dendritestructures and obvious composition segregation exist in this area, and the ternary eutectic structure (α+δ+Cu3P) is also found. Thus, the existence of the ternary eutectic causes the hot brittlement of alloy, which is the main reason to produce the crack during the hot extrusion of tin bronze cup.

基金项目：

山西省科技攻关资助项目（20120321035-04）

苏晓波（1988-），男，硕士研究生冯再新（1968-），男，博士，教授

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