论文部分内容阅读
使用水浸式相控阵超声波检测技术对7075铝合金预拉伸厚板进行超声波检测。对不合格品进行解剖后,采用光学显微镜、扫描电子显微镜、能谱仪对缺陷进行了分析。在熔体凝固过程中,高熔点合金元素局部富集,优先凝固形核长大,形成粗大化合物。在轧制过程中粗大化合物被破碎和延长,形成超声波检测时发现的缺陷。通过控制返回料的比例,适当提高铸造温度,防止形成Al-Cr-Ti等粗大化合物;适当延长熔炼时间,使中间合金中的粗大化合物熔解。
Ultrasonic testing of 7075 aluminum alloy pre-stretched slab was performed using immersion phased array ultrasonic testing. After analyzing the unqualified products, the defects were analyzed by optical microscope, scanning electron microscope and energy dispersive spectrometer. In the melt solidification process, the high melting point alloy elements locally enriched, preferentially solidified nuclei grew up, the formation of coarse compounds. The coarse compound is broken and lengthened during rolling to form the defects found during the ultrasonic inspection. By controlling the proportion of material to be returned, the casting temperature is appropriately increased to prevent the formation of coarse compounds such as Al-Cr-Ti. The melting time of the coarse compound in the intermediate alloy is appropriately extended.