20#精密鋼管批發零售

　　現貨充足,定制加工各種規格20#精密鋼管,發(fa)(fa)貨快(kuai),報(bao)價低,全國可(ke)發(fa)(fa),我司(si)專業(ye)生產,歡迎咨詢~

　　20#精密鋼管熱處理工藝

　　精密鋼管前奏

　　真空退火優質彈簧鋼、工具(ju)鋼、精密鋼管的(de)(de)絲(si)材，不(bu)銹(xiu)(xiu)鋼制品(pin)及鈦(tai)合金材，作光亮退火均可采用真空處理。退火溫(wen)度(du)愈(yu)低，則要(yao)求真空度(du)愈(yu)高。為防止鉻的(de)(de)蒸發及加速熱傳(chuan)導，一般(ban)采用載氣加熱(保溫(wen))法，并(bing)注(zhu)意對不(bu)銹(xiu)(xiu)鋼和鈦(tai)合金不(bu)宜用氮而應采用氬氣。

　　精密鋼管過程

　　真空(kong)淬(cui)(cui)(cui)(cui)(cui)火(huo)(huo)真空(kong)淬(cui)(cui)(cui)(cui)(cui)火(huo)(huo)爐(lu)(lu)按冷(leng)(leng)卻(que)方(fang)法分(fen)為(wei)(wei)油(you)(you)(you)淬(cui)(cui)(cui)(cui)(cui)和(he)氣(qi)(qi)(qi)(qi)(qi)淬(cui)(cui)(cui)(cui)(cui)兩類，按工位(wei)數(shu)分(fen)為(wei)(wei)單(dan)室(shi)(shi)式和(he)雙(shuang)室(shi)(shi)式，904山(shan)\畏嘲均屬周期式作(zuo)業(ye)爐(lu)(lu)。真空(kong)油(you)(you)(you)淬(cui)(cui)(cui)(cui)(cui)爐(lu)(lu)都是雙(shuang)室(shi)(shi)的(de)(de)(de)(de)(de)，后室(shi)(shi)置(zhi)電加熱元件(jian)，前(qian)室(shi)(shi)的(de)(de)(de)(de)(de)下方(fang)置(zhi)油(you)(you)(you)槽。工件(jian)完成加熱、保溫(wen)后移入前(qian)室(shi)(shi)，關(guan)閉中(zhong)門后向前(qian)室(shi)(shi)充(chong)入惰性(xing)氣(qi)(qi)(qi)(qi)(qi)至大(da)約2.66%26times;lO ～1.01%26times;10 Pa(200～760mm汞柱)，入油(you)(you)(you)。油(you)(you)(you)淬(cui)(cui)(cui)(cui)(cui)易引起(qi)工件(jian)表(biao)面變(bian)(bian)(bian)質。由于(yu)(yu)(yu)(yu)表(biao)面活性(xing)大(da)，在(zai)(zai)(zai)短暫的(de)(de)(de)(de)(de)高(gao)溫(wen)油(you)(you)(you)膜作(zuo)用下即(ji)可發生顯著薄層滲碳(tan)，此(ci)外，碳(tan)黑和(he)油(you)(you)(you)在(zai)(zai)(zai)表(biao)面的(de)(de)(de)(de)(de)粘附對簡化熱處(chu)(chu)(chu)理(li)流(liu)程很不利。真空(kong)淬(cui)(cui)(cui)(cui)(cui)火(huo)(huo)技術的(de)(de)(de)(de)(de)發展主(zhu)要在(zai)(zai)(zai)于(yu)(yu)(yu)(yu)研(yan)制性(xing)能(neng)(neng)優良、工位(wei)單(dan)一的(de)(de)(de)(de)(de)氣(qi)(qi)(qi)(qi)(qi)冷(leng)(leng)淬(cui)(cui)(cui)(cui)(cui)火(huo)(huo)爐(lu)(lu)。前(qian)述(shu)雙(shuang)室(shi)(shi)式爐(lu)(lu)亦(yi)可用于(yu)(yu)(yu)(yu)氣(qi)(qi)(qi)(qi)(qi)淬(cui)(cui)(cui)(cui)(cui)(在(zai)(zai)(zai)前(qian)室(shi)(shi)噴氣(qi)(qi)(qi)(qi)(qi)冷(leng)(leng)卻(que))，但雙(shuang)工位(wei)式的(de)(de)(de)(de)(de)操(cao)作(zuo)使大(da)批量(liang)裝爐(lu)(lu)的(de)(de)(de)(de)(de)生產發生困難，也易在(zai)(zai)(zai)高(gao)溫(wen)移動中(zhong)引起(qi)工件(jian)變(bian)(bian)(bian)形或改變(bian)(bian)(bian)工件(jian)方(fang)位(wei)增(zeng)加淬(cui)(cui)(cui)(cui)(cui)火(huo)(huo)變(bian)(bian)(bian)形。單(dan)一工位(wei)的(de)(de)(de)(de)(de)氣(qi)(qi)(qi)(qi)(qi)冷(leng)(leng)淬(cui)(cui)(cui)(cui)(cui)火(huo)(huo)爐(lu)(lu)是在(zai)(zai)(zai)加熱保溫(wen)完成后在(zai)(zai)(zai)加熱室(shi)(shi)內噴氣(qi)(qi)(qi)(qi)(qi)冷(leng)(leng)卻(que)。氣(qi)(qi)(qi)(qi)(qi)冷(leng)(leng)的(de)(de)(de)(de)(de)冷(leng)(leng)速(su)不如油(you)(you)(you)冷(leng)(leng)快，也低于(yu)(yu)(yu)(yu)傳(chuan)統淬(cui)(cui)(cui)(cui)(cui)火(huo)(huo)法中(zhong)的(de)(de)(de)(de)(de)熔鹽等溫(wen)、分(fen)級淬(cui)(cui)(cui)(cui)(cui)火(huo)(huo)。因而，不斷提高(gao)噴冷(leng)(leng)室(shi)(shi)壓(ya)力，增(zeng)大(da)流(liu)量(liang)，以及采用摩(mo)爾質量(liang)比氮(dan)(dan)和(he)氬小的(de)(de)(de)(de)(de)惰性(xing)氣(qi)(qi)(qi)(qi)(qi)體氦和(he)氫(qing)，是當今真空(kong)淬(cui)(cui)(cui)(cui)(cui)火(huo)(huo)技術發展的(de)(de)(de)(de)(de)主(zhu)流(liu)。70年(nian)(nian)代(dai)后期將氮(dan)(dan)氣(qi)(qi)(qi)(qi)(qi)噴冷(leng)(leng)的(de)(de)(de)(de)(de)壓(ya)力從(1～2)%26times;10Pa提高(gao)到(dao)(5～6)%26times;10Pa，使冷(leng)(leng)卻(que)能(neng)(neng)力接近于(yu)(yu)(yu)(yu)常(chang)壓(ya)下的(de)(de)(de)(de)(de)油(you)(you)(you)冷(leng)(leng)。80年(nian)(nian)代(dai)中(zhong)期出現(xian)超(chao)高(gao)壓(ya)氣(qi)(qi)(qi)(qi)(qi)淬(cui)(cui)(cui)(cui)(cui)，用(10～20)%26times;10Pa的(de)(de)(de)(de)(de)氦，冷(leng)(leng)卻(que)能(neng)(neng)力等于(yu)(yu)(yu)(yu)或略高(gao)于(yu)(yu)(yu)(yu)油(you)(you)(you)淬(cui)(cui)(cui)(cui)(cui)，已進(jin)入工業(ye)實用。90年(nian)(nian)代(dai)初采用40%26times;10Pa的(de)(de)(de)(de)(de)氫(qing)氣(qi)(qi)(qi)(qi)(qi)，接近水淬(cui)(cui)(cui)(cui)(cui)的(de)(de)(de)(de)(de)冷(leng)(leng)卻(que)能(neng)(neng)力，尚處(chu)(chu)(chu)于(yu)(yu)(yu)(yu)起(qi)步階(jie)段。工業(ye)發達國(guo)家已進(jin)展到(dao)以高(gao)壓(ya)(5～6)%26times;10。Pa氣(qi)(qi)(qi)(qi)(qi)淬(cui)(cui)(cui)(cui)(cui)為(wei)(wei)主(zhu)體，而中(zhong)國(guo)產氣(qi)(qi)(qi)(qi)(qi)淬(cui)(cui)(cui)(cui)(cui)一些金屬的(de)(de)(de)(de)(de)蒸氣(qi)(qi)(qi)(qi)(qi)壓(ya)(理(li)論值)與溫(wen)度的(de)(de)(de)(de)(de)關(guan)系則尚處(chu)(chu)(chu)于(yu)(yu)(yu)(yu)一般加壓(ya)氣(qi)(qi)(qi)(qi)(qi)淬(cui)(cui)(cui)(cui)(cui)(2%26times;10Pa)型階(jie)段。

　　結果(guo)真空(kong)(kong)滲(shen)(shen)碳(tan)(tan)(tan)為真空(kong)(kong)滲(shen)(shen)碳(tan)(tan)(tan)一(yi)淬(cui)火(huo)工藝曲線。在真空(kong)(kong)中加熱到(dao)滲(shen)(shen)碳(tan)(tan)(tan)溫(wen)度(du)并保溫(wen)使(shi)(shi)表(biao)面凈化、活(huo)化之(zhi)后，通(tong)入稀薄滲(shen)(shen)碳(tan)(tan)(tan)富(fu)化氣(qi)(qi)(qi)(見控(kong)制氣(qi)(qi)(qi)氛熱處(chu)理)，在大約(yue)1330Pa(10T0rr)負(fu)壓(ya)下進(jin)行(xing)(xing)滲(shen)(shen)入，然后停(ting)氣(qi)(qi)(qi)(降壓(ya))進(jin)行(xing)(xing)擴(kuo)散。滲(shen)(shen)碳(tan)(tan)(tan)后的精密鋼管淬(cui)火(huo)采(cai)用(yong)(yong)一(yi)次(ci)淬(cui)火(huo)法，即(ji)先停(ting)電，通(tong)氮冷卻(que)工件至(zhi)臨界點A，、以下，使(shi)(shi)內部發(fa)生(sheng)相變，再停(ting)氣(qi)(qi)(qi)、開泵(beng)，升溫(wen)到(dao)Ac1，～Accm之(zhi)間。淬(cui)冷方法可(ke)(ke)采(cai)用(yong)(yong)氣(qi)(qi)(qi)冷或油(you)冷。后者為奧氏體(ti)(ti)化后移(yi)入前室，充(chong)氮至(zhi)常壓(ya)，入油(you)。真空(kong)(kong)滲(shen)(shen)碳(tan)(tan)(tan)的溫(wen)度(du)一(yi)般高(gao)于普通(tong)氣(qi)(qi)(qi)體(ti)(ti)滲(shen)(shen)碳(tan)(tan)(tan)，常采(cai)用(yong)(yong)920～1040℃滲(shen)(shen)入和擴(kuo)散可(ke)(ke)按所示分(fen)兩階(jie)段，也可(ke)(ke)用(yong)(yong)脈沖式(shi)通(tong)氣(qi)(qi)(qi)、停(ting)氣(qi)(qi)(qi)，多(duo)段式(shi)的滲(shen)(shen)一(yi)擴(kuo)相間，效果(guo)更好。由于溫(wen)度(du)高(gao)，尤(you)其(qi)表(biao)面潔凈、有活(huo)性，真空(kong)(kong)滲(shen)(shen)碳(tan)(tan)(tan)層形成速度(du)比普通(tong)氣(qi)(qi)(qi)體(ti)(ti)、液體(ti)(ti)和固體(ti)(ti)滲(shen)(shen)碳(tan)(tan)(tan)快，如要求(qiu)滲(shen)(shen)層為1mm時，在927℃只需(xu)5h，而1033℃僅需(xu)1h。

　　精密鋼管(guan)硬度與變形

　　取兩塊(kuai)式樣，一塊(kuai)用(yong)于研究不同(tong)形變程度對硬(ying)度的影(ying)響(xiang)，另一塊(kuai)研究不同(tong)溫度對性能(neng)的影(ying)響(xiang)。

　　冷(leng)(leng)變(bian)(bian)(bian)(bian)(bian)形(xing)(xing)強化(hua)在實際生產(chan)中具有(you)重(zhong)要的(de)(de)意義。首先這是一種重(zhong)要的(de)(de)強化(hua)材(cai)料的(de)(de)手段，尤其(qi)對(dui)用(yong)熱(re)處理不(bu)能強化(hua)的(de)(de)材(cai)料來(lai)說，顯得更為重(zhong)要。其(qi)次，冷(leng)(leng)變(bian)(bian)(bian)(bian)(bian)形(xing)(xing)強化(hua)有(you)利于(yu)金屬(shu)的(de)(de)變(bian)(bian)(bian)(bian)(bian)形(xing)(xing)均勻。因(yin)為精密鋼管的(de)(de)變(bian)(bian)(bian)(bian)(bian)形(xing)(xing)部分產(chan)生硬化(hua)，將使變(bian)(bian)(bian)(bian)(bian)形(xing)(xing)向未變(bian)(bian)(bian)(bian)(bian)形(xing)(xing)或變(bian)(bian)(bian)(bian)(bian)形(xing)(xing)較少的(de)(de)部分繼(ji)續發展。第三，冷(leng)(leng)變(bian)(bian)(bian)(bian)(bian)形(xing)(xing)強化(hua)可以提(ti)高構(gou)件在使用(yong)過程中的(de)(de)安(an)全性，構(gou)件一旦超載，產(chan)生塑性變(bian)(bian)(bian)(bian)(bian)形(xing)(xing)，由于(yu)強化(hua)作用(yong)，可防止構(gou)件突然(ran)斷裂。但是，冷(leng)(leng)變(bian)(bian)(bian)(bian)(bian)形(xing)(xing)強化(hua)也給精密鋼管的(de)(de)繼(ji)續變(bian)(bian)(bian)(bian)(bian)形(xing)(xing)帶來(lai)困難，甚至(zhi)出現裂紋(wen)。因(yin)此，在精密鋼管變(bian)(bian)(bian)(bian)(bian)形(xing)(xing)和加工(gong)過程中常進行"中間退火"，以消除它的(de)(de)不(bu)利影響。