在金属铸造业中,围绕铸件缺陷究竟是热裂或是收缩所形成,常常争辩得很激烈。关于这问题的一个重要线索,乃是视其表面的颜色而定,因为在金属凝固或半凝固状态下常发生热裂,观察其表面的颜色是很重要的。一般说来,只要供给足够的热量氧化到一定程度,就有发生热裂的可能性,但遗憾的是收缩也可能有那样的变色。 In the metal foundry industry, casting defects are often caused by thermal cracking or shrinkage, often arguing intensely. An important clue about this issue depends on the color of its surface. Because thermal cracking often occurs in solidified or semi-solidified metal, it is important to observe the color of its surface. In general, as long as enough heat is supplied to oxidize to a certain extent, there is a possibility of thermal cracking, but regrettably, shrinkage may also have such discoloration.