熱處理對于有高硬度、高耐磨性和高韌性要求的塑料模具，表面熱處理廠家要選用滲碳鋼來制造，并把滲碳、淬火和低溫回火作為最終熱處理，表面熱處理廠家對滲碳層(ceng)(ceng)的(de)(de)要求，一般滲碳層(ceng)(ceng)的(de)(de)厚度為(wei)(wei)o．8—1．5mm，當壓制含硬質填(tian)料的(de)(de)塑料時，模具滲碳層(ceng)(ceng)厚度要求為(wei)(wei)1．3~15mm，壓制軟性(xing)(xing)塑料時滲碳層(ceng)(ceng)厚度為(wei)(wei)0.8~1．2mm。滲碳層(ceng)(ceng)的(de)(de)碳含量為(wei)(wei)0.7％~1.0％為(wei)(wei)佳。若采用碳氮共滲，則耐磨性(xing)(xing)、耐腐蝕性(xing)(xing)、抗(kang)氧化(hua)、防(fang)粘(zhan)性(xing)(xing)就(jiu)更好。

滲(shen)(shen)碳(tan)溫(wen)(wen)度(du)一般在900—920攝(she)氏度(du)之間，復雜型腔的(de)小(xiao)型模(mo)具（模(mo)具鋼）可(ke)取840—860攝(she)氏度(du)中溫(wen)(wen)碳(tan)氮共滲(shen)(shen)。滲(shen)(shen)碳(tan)保溫(wen)(wen)時間為1~l0h．具體應根據對滲(shen)(shen)層(ceng)厚(hou)度(du)的(de)要求來選(xuan)擇。滲(shen)(shen)碳(tan)工藝以采用(yong)分級滲(shen)(shen)碳(tan)工藝為宜，即高溫(wen)(wen)階(jie)段(900—920攝(she)氏度(du))以快速將碳(tan)滲(shen)(shen)入零件(jian)表層(ceng)為主(zhu)．中溫(wen)(wen)階(jie)段(820~840攝(she)氏度(du))以增加(jia)滲(shen)(shen)碳(tan)層(ceng)厚(hou)度(du)為主(zhu)，這樣在滲(shen)(shen)碳(tan)層(ceng)內建立均勻(yun)合理的(de)碳(tan)濃度(du)梯度(du)分布，便于(yu)直(zhi)接淬(cui)火(huo)。

提高(gao)韌(ren)性(xing)的球墨(mo)(mo)(mo)(mo)鑄(zhu)(zhu)鐵(tie)(tie)(tie)(tie)(tie)退火(huo)球墨(mo)(mo)(mo)(mo)鑄(zhu)(zhu)鐵(tie)(tie)(tie)(tie)(tie)在鑄(zhu)(zhu)造過(guo)程(cheng)中此普通灰(hui)口(kou)鑄(zhu)(zhu)鐵(tie)(tie)(tie)(tie)(tie)的白口(kou)傾向大，內應力也(ye)較大，鑄(zhu)(zhu)鐵(tie)(tie)(tie)(tie)(tie)件(jian)(jian)很難(nan)得到(dao)純粹的鐵(tie)(tie)(tie)(tie)(tie)素(su)(su)體(ti)(ti)(ti)(ti)(ti)(ti)(ti)或(huo)珠(zhu)光(guang)體(ti)(ti)(ti)(ti)(ti)(ti)(ti)基(ji)體(ti)(ti)(ti)(ti)(ti)(ti)(ti)，為(wei)(wei)提高(gao)鑄(zhu)(zhu)鐵(tie)(tie)(tie)(tie)(tie)件(jian)(jian)的延性(xing)或(huo)韌(ren)性(xing)，常將(jiang)(jiang)鑄(zhu)(zhu)鐵(tie)(tie)(tie)(tie)(tie)件(jian)(jian)重(zhong)新加熱到(dao)900-950℃并保(bao)溫(wen)(wen)足(zu)夠時(shi)間進行高(gao)溫(wen)(wen)退火(huo)，再爐冷到(dao)600℃出(chu)爐變(bian)冷。若鑄(zhu)(zhu)態(tai)組織(zhi)由(鐵(tie)(tie)(tie)(tie)(tie)素(su)(su)體(ti)(ti)(ti)(ti)(ti)(ti)(ti)＋珠(zhu)光(guang)體(ti)(ti)(ti)(ti)(ti)(ti)(ti))基(ji)體(ti)(ti)(ti)(ti)(ti)(ti)(ti)，以及球狀石(shi)墨(mo)(mo)(mo)(mo)組成，為(wei)(wei)提高(gao)韌(ren)性(xing)，只需將(jiang)(jiang)珠(zhu)光(guang)體(ti)(ti)(ti)(ti)(ti)(ti)(ti)中滲碳體(ti)(ti)(ti)(ti)(ti)(ti)(ti)分解(jie)轉換為(wei)(wei)鐵(tie)(tie)(tie)(tie)(tie)素(su)(su)體(ti)(ti)(ti)(ti)(ti)(ti)(ti)及球狀石(shi)墨(mo)(mo)(mo)(mo)，為(wei)(wei)此將(jiang)(jiang)鑄(zhu)(zhu)鐵(tie)(tie)(tie)(tie)(tie)件(jian)(jian)重(zhong)新加熱到(dao)700-760℃的共(gong)析溫(wen)(wen)度(du)上下經保(bao)溫(wen)(wen)后爐冷至600℃出(chu)爐變(bian)冷。工藝過(guo)程(cheng)是將(jiang)(jiang)基(ji)體(ti)(ti)(ti)(ti)(ti)(ti)(ti)為(wei)(wei)鐵(tie)(tie)(tie)(tie)(tie)素(su)(su)體(ti)(ti)(ti)(ti)(ti)(ti)(ti)及珠(zhu)光(guang)體(ti)(ti)(ti)(ti)(ti)(ti)(ti)的球墨(mo)(mo)(mo)(mo)鑄(zhu)(zhu)鐵(tie)(tie)(tie)(tie)(tie)件(jian)(jian)重(zhong)新加熱到(dao)850-900℃溫(wen)(wen)度(du)，原鐵(tie)(tie)(tie)(tie)(tie)素(su)(su)體(ti)(ti)(ti)(ti)(ti)(ti)(ti)及珠(zhu)光(guang)體(ti)(ti)(ti)(ti)(ti)(ti)(ti)轉換為(wei)(wei)奧氏(shi)體(ti)(ti)(ti)(ti)(ti)(ti)(ti)，并有部分球狀石(shi)墨(mo)(mo)(mo)(mo)溶解(jie)于奧氏(shi)體(ti)(ti)(ti)(ti)(ti)(ti)(ti)，經保(bao)溫(wen)(wen)后空冷奧氏(shi)體(ti)(ti)(ti)(ti)(ti)(ti)(ti)轉變(bian)為(wei)(wei)細珠(zhu)光(guang)體(ti)(ti)(ti)(ti)(ti)(ti)(ti)，因此鑄(zhu)(zhu)件(jian)(jian)的強度(du)提高(gao)。