順徳熱處理的(de)袁組(zu)長(chang)告(gao)訴大家(jia)零(ling)(ling)件(jian)加(jia)熱(re)(re)(re)溫度過(guo)(guo)高或(huo)(huo)保(bao)溫時間過(guo)(guo)長(chang)，使先共(gong)析相(xiang)溶入奧(ao)氏(shi)體(ti)(ti)、并使奧(ao)氏(shi)體(ti)(ti)晶(jing)(jing)(jing)粒(li)粗(cu)大的(de)現象稱為過(guo)(guo)燒(shao)(shao)，過(guo)(guo)燒(shao)(shao)還使晶(jing)(jing)(jing)界(jie)出(chu)現熔融(rong)狀態。過(guo)(guo)燒(shao)(shao)會(hui)導致在(zai)以后的(de)珠(zhu)光體(ti)(ti)轉變過(guo)(guo)程(cheng)中(zhong)得(de)不到(dao)理(li)想組(zu)織，使零(ling)(ling)件(jian)塑性(xing)(xing)、韌性(xing)(xing)降低(di)，脆性(xing)(xing)增(zeng)加(jia)。中(zhong)碳(tan)鋼(gang)和中(zhong)碳(tan)合金鋼(gang)過(guo)(guo)熱(re)(re)(re)后在(zai)一(yi)定冷速下(xia)還會(hui)形成(cheng)魏(wei)氏(shi)組(zu)織，過(guo)(guo)燒(shao)(shao)還使零(ling)(ling)件(jian)出(chu)現石狀斷口。過(guo)(guo)熱(re)(re)(re)過(guo)(guo)燒(shao)(shao)的(de)原因除了與錯誤工藝規定有關(guan)，還與儀表(biao)失靈、控溫失真(zhen)、示值不準(zhun)、補償導線(xian)接反、熱(re)(re)(re)電(dian)偶老化、爐(lu)氣循環不好、爐(lu)溫不均勻，局(ju)部(bu)溫度過(guo)(guo)高等因素(su)有關(guan)。工人操作時違犯工藝紀律或(huo)(huo)零(ling)(ling)件(jian)離電(dian)極、電(dian)熱(re)(re)(re)絲，感應(ying)器太(tai)近都(dou)會(hui)造成(cheng)局(ju)部(bu)過(guo)(guo)熱(re)(re)(re)過(guo)(guo)燒(shao)(shao)。亞共(gong)析鋼(gang)可以用xx退火xx晶(jing)(jing)(jing)粒(li)粗(cu)大。