一、引 言 所谓“铜层内裂纹”,就是在ZQPb30双金属轴承横截面的铜层之间,沿圆周方向产生的一种圆弧形裂纹。由于它产生于铜层的内部,故称之为“铜层内裂纹”(以下简称为内裂纹)。严重的内裂纹在铜层上形成一整圈,将铜层分割为内外两层,如图1所示。较轻的内裂纹为一段弧形裂纹。 I. INTRODUCTION The so-called “crack in the copper layer” is an arc-shaped crack that occurs in the circumferential direction between the copper layers of the ZQPb30 bimetal bearing cross-section. Because it is produced in the copper layer inside, it is called “cracks in the copper layer” (hereinafter referred to as internal cracks). Serious internal cracks in the copper layer to form a full circle, the copper layer is divided into two layers inside and outside, as shown in Figure 1. The lighter internal crack is a curved crack.