一、氮氣(qi)孔的形成機理

  在(zai)(zai)21.5Cr5Mn1.5Ni0.25N含氮(dan)(dan)(dan)(dan)(dan)(dan)雙相(xiang)(xiang)(xiang)鋼凝(ning)固(gu)過(guo)程中(zhong)(zhong)(zhong)(zhong)，氮(dan)(dan)(dan)(dan)(dan)(dan)氣(qi)孔形(xing)成(cheng)(cheng)和凝(ning)固(gu)前(qian)沿處(chu)［％N]1iq隨距離變化(hua)的(de)(de)(de)(de)(de)(de)(de)(de)規律如(ru)(ru)(ru)圖2-55所(suo)示。由于(yu)糊(hu)狀(zhuang)(zhuang)區(qu)內(nei)(nei)大量枝晶(jing)網狀(zhuang)(zhuang)結構的(de)(de)(de)(de)(de)(de)(de)(de)形(xing)成(cheng)(cheng)，液(ye)相(xiang)(xiang)(xiang)的(de)(de)(de)(de)(de)(de)(de)(de)對流只存在(zai)(zai)于(yu)一(yi)次枝晶(jing)尖端位置附近。且(qie)枝晶(jing)間幾乎無液(ye)相(xiang)(xiang)(xiang)的(de)(de)(de)(de)(de)(de)(de)(de)流動。因此(ci)，枝晶(jing)間殘(can)(can)余液(ye)相(xiang)(xiang)(xiang)中(zhong)(zhong)(zhong)(zhong)的(de)(de)(de)(de)(de)(de)(de)(de)氮(dan)(dan)(dan)(dan)(dan)(dan)傳質(zhi)主(zhu)要(yao)依靠氮(dan)(dan)(dan)(dan)(dan)(dan)的(de)(de)(de)(de)(de)(de)(de)(de)擴散行為，且(qie)糊(hu)狀(zhuang)(zhuang)區(qu)內(nei)(nei)氮(dan)(dan)(dan)(dan)(dan)(dan)傳質(zhi)速率非常小。初始(shi)(shi)相(xiang)(xiang)(xiang)貧(pin)(pin)氮(dan)(dan)(dan)(dan)(dan)(dan)鐵素(su)體相(xiang)(xiang)(xiang)8的(de)(de)(de)(de)(de)(de)(de)(de)氮(dan)(dan)(dan)(dan)(dan)(dan)溶解(jie)度和糊(hu)狀(zhuang)(zhuang)區(qu)的(de)(de)(de)(de)(de)(de)(de)(de)氮(dan)(dan)(dan)(dan)(dan)(dan)傳質(zhi)速率較低，導致在(zai)(zai)貧(pin)(pin)氮(dan)(dan)(dan)(dan)(dan)(dan)鐵素(su)體相(xiang)(xiang)(xiang)枝晶(jing)附近的(de)(de)(de)(de)(de)(de)(de)(de)液(ye)相(xiang)(xiang)(xiang)中(zhong)(zhong)(zhong)(zhong)出現(xian)氮(dan)(dan)(dan)(dan)(dan)(dan)富集(ji)，且(qie)［％N]iq迅速增大，如(ru)(ru)(ru)圖2-55(a)所(suo)示。根據Yang和 Leel70]、Svyazhin 等、Ridolfi 和 Tassal的(de)(de)(de)(de)(de)(de)(de)(de)報道可(ke)知(zhi)，當(dang)［％N]iq的(de)(de)(de)(de)(de)(de)(de)(de)最大值超過(guo)氮(dan)(dan)(dan)(dan)(dan)(dan)氣(qi)泡(pao)形(xing)成(cheng)(cheng)的(de)(de)(de)(de)(de)(de)(de)(de)臨界(jie)氮(dan)(dan)(dan)(dan)(dan)(dan)質(zhi)量分(fen)數（［％N]pore)時，該區(qu)域有氣(qi)泡(pao)形(xing)成(cheng)(cheng)的(de)(de)(de)(de)(de)(de)(de)(de)可(ke)能(neng)性(xing)，如(ru)(ru)(ru)圖2-55(b)所(suo)示。在(zai)(zai)后(hou)(hou)續的(de)(de)(de)(de)(de)(de)(de)(de)凝(ning)固(gu)過(guo)程中(zhong)(zhong)(zhong)(zhong)，隨著包晶(jing)反應的(de)(de)(de)(de)(de)(de)(de)(de)進(jin)行，富氮(dan)(dan)(dan)(dan)(dan)(dan)奧氏體相(xiang)(xiang)(xiang)γ以(yi)異質(zhi)形(xing)核(he)的(de)(de)(de)(de)(de)(de)(de)(de)方(fang)式在(zai)(zai)鐵素(su)體相(xiang)(xiang)(xiang)8枝晶(jing)的(de)(de)(de)(de)(de)(de)(de)(de)表(biao)面(mian)開始(shi)(shi)形(xing)核(he)長(chang)大，逐漸包裹鐵素(su)體相(xiang)(xiang)(xiang)枝晶(jing)表(biao)面(mian)，并開始(shi)(shi)捕獲殘(can)(can)余液(ye)相(xiang)(xiang)(xiang)中(zhong)(zhong)(zhong)(zhong)的(de)(de)(de)(de)(de)(de)(de)(de)氮(dan)(dan)(dan)(dan)(dan)(dan)氣(qi)泡(pao)，對比圖2-51和圖2-56可(ke)知(zhi)，此(ci)時枝晶(jing)間殘(can)(can)余［％N]1ig的(de)(de)(de)(de)(de)(de)(de)(de)增長(chang)速率減小。對平衡凝(ning)固(gu)而(er)言，殘(can)(can)余液(ye)相(xiang)(xiang)(xiang)中(zhong)(zhong)(zhong)(zhong)氮(dan)(dan)(dan)(dan)(dan)(dan)氣(qi)泡(pao)形(xing)成(cheng)(cheng)以(yi)后(hou)(hou)，氮(dan)(dan)(dan)(dan)(dan)(dan)的(de)(de)(de)(de)(de)(de)(de)(de)富集(ji)程度減弱，［％N]1iq增長(chang)速率的(de)(de)(de)(de)(de)(de)(de)(de)減小程度明顯；相(xiang)(xiang)(xiang)比之下，Scheil凝(ning)固(gu)過(guo)程中(zhong)(zhong)(zhong)(zhong)，氮(dan)(dan)(dan)(dan)(dan)(dan)氣(qi)泡(pao)形(xing)成(cheng)(cheng)以(yi)后(hou)(hou)，殘(can)(can)余液(ye)相(xiang)(xiang)(xiang)中(zhong)(zhong)(zhong)(zhong)氮(dan)(dan)(dan)(dan)(dan)(dan)富集(ji)狀(zhuang)(zhuang)態(tai)有所(suo)緩解(jie)，但幅度很小。隨著凝(ning)固(gu)界(jie)面(mian)的(de)(de)(de)(de)(de)(de)(de)(de)進(jin)一(yi)步推移，被捕獲的(de)(de)(de)(de)(de)(de)(de)(de)氮(dan)(dan)(dan)(dan)(dan)(dan)氣(qi)泡(pao)在(zai)(zai)奧氏體相(xiang)(xiang)(xiang)表(biao)面(mian)開始(shi)(shi)長(chang)大，并沿凝(ning)固(gu)方(fang)向拉長(chang)，如(ru)(ru)(ru)圖2-55(c)所(suo)示。

  氮氣(qi)孔(kong)沿徑向生(sheng)長，生(sheng)長方向與凝固(gu)方向一致，那么氮氣(qi)孔(kong)初(chu)始形(xing)(xing)成位置靠近鑄錠邊(bian)(bian)部，且氮氣(qi)泡初(chu)始位置邊(bian)(bian)緣(yuan)全由(you)奧氏體(ti)相γ構成（圖(tu)2-57中I區(qu)），與圖(tu)2-55描述相符。隨著氮氣(qi)孔(kong)被(bei)拉(la)長，鐵(tie)素體(ti)相和奧氏體(ti)相以體(ti)積分(fen)數比約(yue)為0.92的關系交替在(zai)氮氣(qi)泡周圍(wei)形(xing)(xing)成，直到氮氣(qi)孔(kong)閉合(he)。凝固(gu)結束后，氮氣(qi)孔(kong)的宏(hong)觀(guan)形(xing)(xing)貌類似于(yu)橢圓形(xing)(xing)，與Wei等的研究(jiu)結果一致

二、氮微觀偏(pian)析對氮氣(qi)孔的影(ying)響(xiang)

  氮(dan)的(de)(de)(de)(de)(de)(de)分配(pei)系數(shu)(shu)(shu)較(jiao)小(xiao)，導致液(ye)(ye)(ye)相(xiang)向(xiang)固(gu)(gu)(gu)相(xiang)轉(zhuan)變的(de)(de)(de)(de)(de)(de)過(guo)(guo)程(cheng)中(zhong)(zhong)(zhong)(zhong)，固(gu)(gu)(gu)相(xiang)會將多(duo)余的(de)(de)(de)(de)(de)(de)氮(dan)轉(zhuan)移到殘余液(ye)(ye)(ye)相(xiang)中(zhong)(zhong)(zhong)(zhong)，形(xing)(xing)成(cheng)(cheng)氮(dan)偏析(xi)。在氮(dan)偏析(xi)程(cheng)度逐漸加重的(de)(de)(de)(de)(de)(de)過(guo)(guo)程(cheng)中(zhong)(zhong)(zhong)(zhong)，當殘余液(ye)(ye)(ye)相(xiang)中(zhong)(zhong)(zhong)(zhong)氮(dan)質量分數(shu)(shu)(shu)超過(guo)(guo)其飽和度時(shi)，極易形(xing)(xing)成(cheng)(cheng)氮(dan)氣(qi)(qi)(qi)泡(pao)(pao)。隨著凝(ning)(ning)固(gu)(gu)(gu)的(de)(de)(de)(de)(de)(de)進行，若氣(qi)(qi)(qi)泡(pao)(pao)無(wu)法(fa)上浮而被(bei)捕獲，凝(ning)(ning)固(gu)(gu)(gu)結(jie)束后就會在鑄(zhu)錠內部形(xing)(xing)成(cheng)(cheng)氣(qi)(qi)(qi)孔(kong)。因此，凝(ning)(ning)固(gu)(gu)(gu)過(guo)(guo)程(cheng)中(zhong)(zhong)(zhong)(zhong)氮(dan)偏析(xi)和溶解度對鑄(zhu)錠中(zhong)(zhong)(zhong)(zhong)最終(zhong)氮(dan)氣(qi)(qi)(qi)孔(kong)的(de)(de)(de)(de)(de)(de)形(xing)(xing)成(cheng)(cheng)有(you)至關(guan)重要(yao)的(de)(de)(de)(de)(de)(de)作用(yong)。氮(dan)氣(qi)(qi)(qi)孔(kong)多(duo)數(shu)(shu)(shu)情況下與疏(shu)松(song)縮(suo)孔(kong)共存(cun)，內壁(bi)凹凸不平呈現裂紋(wen)狀，且(qie)整個氣(qi)(qi)(qi)孔(kong)形(xing)(xing)狀不規(gui)則，如圖2-58所(suo)示。此類氣(qi)(qi)(qi)孔(kong)不僅與鋼(gang)(gang)液(ye)(ye)(ye)中(zhong)(zhong)(zhong)(zhong)氣(qi)(qi)(qi)泡(pao)(pao)的(de)(de)(de)(de)(de)(de)形(xing)(xing)成(cheng)(cheng)有(you)關(guan)，還受凝(ning)(ning)固(gu)(gu)(gu)收縮(suo)等(deng)因素(su)的(de)(de)(de)(de)(de)(de)影響，且(qie)多(duo)數(shu)(shu)(shu)分布(bu)于鑄(zhu)錠心(xin)部，尤其在中(zhong)(zhong)(zhong)(zhong)心(xin)等(deng)軸(zhou)(zhou)晶區(qu)。這主要(yao)由(you)于中(zhong)(zhong)(zhong)(zhong)心(xin)等(deng)軸(zhou)(zhou)晶區(qu)內枝晶生(sheng)長較(jiao)發達，容易形(xing)(xing)成(cheng)(cheng)復雜的(de)(de)(de)(de)(de)(de)網狀結(jie)構，從(cong)而將液(ye)(ye)(ye)相(xiang)分割成(cheng)(cheng)無(wu)數(shu)(shu)(shu)個獨立的(de)(de)(de)(de)(de)(de)液(ye)(ye)(ye)相(xiang)區(qu)域，當發生(sheng)凝(ning)(ning)固(gu)(gu)(gu)收縮(suo)時(shi)，難以進行補縮(suo)，在形(xing)(xing)成(cheng)(cheng)疏(shu)松(song)縮(suo)孔(kong)的(de)(de)(de)(de)(de)(de)同時(shi)，局(ju)部鋼(gang)(gang)液(ye)(ye)(ye)靜壓力降(jiang)低，促使(shi)氮(dan)從(cong)殘余液(ye)(ye)(ye)相(xiang)中(zhong)(zhong)(zhong)(zhong)析(xi)出，從(cong)而形(xing)(xing)成(cheng)(cheng)了氮(dan)氣(qi)(qi)(qi)孔(kong)和疏(shu)松(song)縮(suo)孔(kong)共存(cun)的(de)(de)(de)(de)(de)(de)宏觀缺(que)陷。

  平衡凝(ning)(ning)固時，19Cr14Mn0.9N含氮(dan)奧(ao)氏(shi)體(ti)不(bu)銹鋼殘余(yu)液相中氮(dan)偏析與(yu)體(ti)系(xi)氮(dan)溶解度的(de)(de)差值如圖2-59所示。凝(ning)(ning)固初期鐵素體(ti)阱(jing)（ferrite trap)的(de)(de)形(xing)成，導致氮(dan)溶解度的(de)(de)降低(di)，進而使(shi)氮(dan)偏析與(yu)體(ti)系(xi)氮(dan)溶解度差值呈現出略微增大(da)的(de)(de)趨(qu)勢。但在后續凝(ning)(ning)固過(guo)(guo)程中，隨著鐵素體(ti)阱(jing)的(de)(de)消失(shi)以(yi)及富氮(dan)奧(ao)氏(shi)體(ti)相的(de)(de)不(bu)斷形(xing)成，差值減小(xiao)；在整個(ge)凝(ning)(ning)固過(guo)(guo)程中差值始(shi)終較(jiao)小(xiao)，且變化幅度較(jiao)窄。對于19Cr14Mn0.9N 含氮(dan)奧(ao)氏(shi)體(ti)不(bu)銹鋼，液相中氮(dan)氣(qi)泡的(de)(de)形(xing)成趨(qu)勢較(jiao)小(xiao)，難以(yi)在鑄錠(ding)內(nei)形(xing)成獨立內(nei)壁光(guang)滑的(de)(de)規則(ze)氮(dan)氣(qi)孔。

  此外，目前有人對奧(ao)氏(shi)體鋼(gang)(gang)凝固(gu)(gu)過(guo)程中(zhong)氮(dan)(dan)(dan)氣(qi)孔(kong)的形(xing)(xing)(xing)成(cheng)進行(xing)了(le)(le)大(da)量(liang)研(yan)(yan)究(jiu)，如(ru)Yang和Leel901研(yan)(yan)究(jiu)了(le)(le)奧(ao)氏(shi)體鋼(gang)(gang)16Cr3NixMn(x=9和11)凝固(gu)(gu)過(guo)程中(zhong)壓力和初(chu)始氮(dan)(dan)(dan)質量(liang)分數(shu)等因(yin)素(su)對氮(dan)(dan)(dan)氣(qi)孔(kong)形(xing)(xing)(xing)成(cheng)的影(ying)響規(gui)律(lv)，并(bing)建立了(le)(le)相(xiang)(xiang)(xiang)應(ying)的預測模型(xing)。Ridolfi和Tassal[84]分析(xi)了(le)(le)氮(dan)(dan)(dan)偏析(xi)、合金元(yuan)(yuan)素(su)、冷(leng)卻速率以及(ji)枝晶(jing)間距對奧(ao)氏(shi)體鋼(gang)(gang)中(zhong)氮(dan)(dan)(dan)氣(qi)孔(kong)的影(ying)響規(gui)律(lv)，并(bing)揭示了(le)(le)奧(ao)氏(shi)體鋼(gang)(gang)中(zhong)氮(dan)(dan)(dan)氣(qi)孔(kong)形(xing)(xing)(xing)成(cheng)機(ji)理。然而，目前對于(yu)雙(shuang)(shuang)(shuang)相(xiang)(xiang)(xiang)鋼(gang)(gang)中(zhong)氮(dan)(dan)(dan)氣(qi)孔(kong)形(xing)(xing)(xing)成(cheng)的研(yan)(yan)究(jiu)較(jiao)少，且主要(yao)集中(zhong)在(zai)合金元(yuan)(yuan)素(su)、鑄造(zao)方式、冷(leng)卻速率等因(yin)素(su)對氮(dan)(dan)(dan)氣(qi)孔(kong)影(ying)響規(gui)律(lv)的研(yan)(yan)究(jiu)，鮮(xian)有對雙(shuang)(shuang)(shuang)相(xiang)(xiang)(xiang)鋼(gang)(gang)中(zhong)氮(dan)(dan)(dan)氣(qi)孔(kong)形(xing)(xing)(xing)成(cheng)機(ji)理的報道(dao)。以21.5Cr5Mn1.5Ni0.25N含氮(dan)(dan)(dan)雙(shuang)(shuang)(shuang)相(xiang)(xiang)(xiang)鋼(gang)(gang)為例，氮(dan)(dan)(dan)偏析(xi)與溶(rong)解度的差值(zhi)在(zai)整個凝固(gu)(gu)過(guo)程中(zhong)的變化趨(qu)勢，如(ru)圖2-59所(suo)示。隨(sui)著(zhu)凝固(gu)(gu)的進行(xing)，氮(dan)(dan)(dan)偏析(xi)始終大(da)于(yu)氮(dan)(dan)(dan)溶(rong)解度，且差值(zhi)呈現出快速增大(da)的趨(qu)勢。因(yin)此，在(zai)21.5Cr5Mn1.5Ni0.25N 含氮(dan)(dan)(dan)雙(shuang)(shuang)(shuang)相(xiang)(xiang)(xiang)鋼(gang)(gang)凝固(gu)(gu)過(guo)程中(zhong)，氮(dan)(dan)(dan)偏析(xi)嚴重，殘余液相(xiang)(xiang)(xiang)內氮(dan)(dan)(dan)氣(qi)泡形(xing)(xing)(xing)成(cheng)趨(qu)勢較(jiao)大(da)，明顯高于(yu)19Cr14Mn0.9N含氮(dan)(dan)(dan)奧(ao)氏(shi)體不銹鋼(gang)(gang)。

  氮(dan)氣(qi)(qi)泡(pao)形(xing)成和(he)長大具有重(zhong)要的作用（圖2-60).其中(zhong)，σ為氣(qi)(qi)液界面(mian)的表面(mian)張力(li)，r為氣(qi)(qi)泡(pao)半徑(jing)。結合經(jing)典形(xing)核理論，氮(dan)氣(qi)(qi)泡(pao)在鋼液中(zhong)穩定存(cun)在的必(bi)要條(tiao)件為氣(qi)(qi)泡(pao)內壓(ya)力(li)大于作用于氣(qi)(qi)泡(pao)的所有壓(ya)力(li)之和(he)，即(ji)

  式中(zhong)，Aso由(you)(you)凝固過程中(zhong)除氮(dan)(dan)(dan)以外其他合(he)金元素的微觀偏(pian)析(xi)(xi)進行計(ji)算(suan)，其值(zhi)隨著(zhu)(zhu)枝(zhi)晶間殘余(yu)(yu)液(ye)相(xiang)中(zhong)氮(dan)(dan)(dan)溶解度(du)的增(zeng)加而減小，表征了枝(zhi)晶間殘余(yu)(yu)液(ye)相(xiang)中(zhong)氮(dan)(dan)(dan)溶解度(du)對(dui)氮(dan)(dan)(dan)氣泡形成的影響程度(du)；Ase表征了枝(zhi)晶間氮(dan)(dan)(dan)偏(pian)析(xi)(xi)對(dui)氮(dan)(dan)(dan)氣泡形成的影響程度(du)，可由(you)(you)凝固過程中(zhong)枝(zhi)晶間殘余(yu)(yu)液(ye)相(xiang)中(zhong)氮(dan)(dan)(dan)偏(pian)析(xi)(xi)計(ji)算(suan)獲(huo)得，其值(zhi)隨著(zhu)(zhu)氮(dan)(dan)(dan)偏(pian)析(xi)(xi)的增(zeng)大而增(zeng)大。此外，用于計(ji)算(suan)Aso和Ase時所需的合(he)金元素偏(pian)析(xi)(xi)均由(you)(you)鋼(gang)凝固相(xiang)變(bian)所致。

  氮(dan)(dan)氣(qi)泡(pao)的(de)(de)形(xing)(xing)(xing)核和(he)長大過(guo)程復雜，且影(ying)(ying)(ying)響(xiang)因素眾(zhong)多，包括凝(ning)(ning)固(gu)收(shou)縮、冶煉環境以及坩堝(guo)材(cai)質(zhi)(zhi)等(deng)(deng)。因此(ci)，很(hen)難采用Pg值精確預(yu)測凝(ning)(ning)固(gu)過(guo)程中(zhong)氮(dan)(dan)氣(qi)泡(pao)的(de)(de)形(xing)(xing)(xing)成(cheng)和(he)長大。然(ran)而基于Yang等(deng)(deng)的(de)(de)實驗(yan)研究［70,77],在(zai)評估凝(ning)(ning)固(gu)壓力、合金成(cheng)分等(deng)(deng)因素對氮(dan)(dan)氣(qi)泡(pao)形(xing)(xing)(xing)成(cheng)的(de)(de)影(ying)(ying)(ying)響(xiang)程度時(shi)，Pg起(qi)關鍵作用。實際(ji)凝(ning)(ning)固(gu)過(guo)程介于平(ping)衡(heng)凝(ning)(ning)固(gu)（固(gu)／液相(xiang)(xiang)中(zhong)溶(rong)質(zhi)(zhi)完(wan)全擴(kuo)散(san)）和(he)Scheil凝(ning)(ning)固(gu)（固(gu)相(xiang)(xiang)無溶(rong)質(zhi)(zhi)擴(kuo)散(san)，液相(xiang)(xiang)中(zhong)完(wan)全擴(kuo)散(san)）之間70].因此(ci)，可分別計(ji)算平(ping)衡(heng)凝(ning)(ning)固(gu)和(he)Scheil凝(ning)(ning)固(gu)過(guo)程中(zhong)的(de)(de)Aso、Ase和(he)Pg,闡(chan)明實際(ji)凝(ning)(ning)固(gu)過(guo)程中(zhong)壓力等(deng)(deng)因素對氮(dan)(dan)氣(qi)泡(pao)形(xing)(xing)(xing)成(cheng)的(de)(de)影(ying)(ying)(ying)響(xiang)規律。

  現以(yi)21.5Cr5Mn1.5Ni0.25N含(han)氮雙相鋼D1鑄錠(ding)(ding)為(wei)例，對(dui)凝固過程中Aso、Ase和(he)P8的變化(hua)趨勢進(jin)行計算。圖2-61描(miao)述了ΔAso(=Asa-Aso,0)和(he)AAse(=Ase-Ase,o)隨固相質量分(fen)數的變化(hua)趨勢（Aso,0和(he)Asc,0分(fen)別為(wei)D1鑄錠(ding)(ding)凝固時Aso和(he)Ase的初始值(zhi)）。

  在平衡(heng)凝(ning)(ning)固(gu)(gu)和Scheil凝(ning)(ning)固(gu)(gu)過程(cheng)(cheng)中(zhong)，ΔAso的(de)(de)最(zui)小值(zhi)分別(bie)為(wei)－0.145和－0.397,與(yu)(yu)此(ci)相對(dui)(dui)應的(de)(de)ΔAse值(zhi)最(zui)大，分別(bie)為(wei)0.68和0.92.在整(zheng)個(ge)凝(ning)(ning)固(gu)(gu)過程(cheng)(cheng)中(zhong)，由于ΔAse與(yu)(yu)ΔAso之和始(shi)終大于零，因而枝晶間殘余液相中(zhong)氮(dan)偏析對(dui)(dui)D1 鑄(zhu)錠(ding)凝(ning)(ning)固(gu)(gu)過程(cheng)(cheng)中(zhong)氮(dan)氣泡形(xing)(xing)成的(de)(de)影(ying)響大于氮(dan)溶(rong)解度，起主導(dao)作用。此(ci)外，在整(zheng)個(ge)凝(ning)(ning)固(gu)(gu)過程(cheng)(cheng)中(zhong)，P8變化(hua)趨勢如圖2-62所示(shi)，其變化(hua)規律與(yu)(yu)Young等。的(de)(de)研究結(jie)果一致(zhi)，Pg的(de)(de)最(zui)大值(zhi)Pg與(yu)(yu)Ase+Aso的(de)(de)最(zui)大值(zhi)相對(dui)(dui)應，且在平衡(heng)凝(ning)(ning)固(gu)(gu)和 Scheil 凝(ning)(ning)固(gu)(gu)過程(cheng)(cheng)中(zhong)分別(bie)為(wei)0.63MPa和0.62MPa.此(ci)外，可通過對(dui)(dui)比(bi)不同鑄(zhu)錠(ding)中(zhong)的(de)(de)探討凝(ning)(ning)固(gu)(gu)壓力、初始(shi)氮(dan)質量分數以及合金元素(su)（鉻(ge)和錳）等對(dui)(dui)液相中(zhong)氮(dan)氣泡形(xing)(xing)成的(de)(de)影(ying)響，進而明晰各(ge)因素(su)對(dui)(dui)氮(dan)氣孔形(xing)(xing)成的(de)(de)影(ying)響規律。