图1所示为灰铸铁反应釜,其厚度为60mm。该反应釜在使用过程中,由于釜底长时间受炭火烘烤,釜内温度高达200～300℃,使内外表面温差较大,产生的热应力也很大,因而常在釜底圆角过渡段产生穿透性裂纹,裂纹长度为700～800mm(见图1)。有时该反应釜使用不到一个月就失效破坏, Figure 1 shows the gray iron reactor, the thickness of 60mm. During the using process of the reaction kettle, since the bottom of the kettle is bake by charcoal fire for a long time, the temperature in the kettle reaches as high as 200-300 DEG C so that the temperature difference between the inner and the outer surfaces is large and the thermal stress is also large, The segment produces a penetrating crack with a crack length of 700 to 800 mm (see Figure 1). Sometimes the reactor less than a month to failure failure,