一、前言 在牌号为HPb59-1的黄铜锻件生产过程中,出现了一种不常见的凹坑缺陷。凹坑为圆形、椭圆形和不规则链状(图1)。凹坑有规律地集中分布在锻件的某一侧(背侧没有),凹坑内有黑色物质。从凹坑处剖开,在放大镜下观察其低倍组织,发现缺陷处组织分为四层(图2)。 First, the foreword In the production of brass forgings grades HPb59-1, there is an unusual pit defects. The dimples are round, oval and irregular (Figure 1). The pits are regularly concentrated on one side of the forgings (dorsal side is not present), and the pits have dark substances. Cut open from the pit, observed under a magnifying glass of its low magnification tissue was found to be divided into four layers of defects (Figure 2).