浸滲劑真空加壓浸滲工藝與浸滲工藝流程

(一)、真空(kong)加(jia)壓浸滲工藝
在(zai)的鋁鑄件生產廠(chang)中，目(mu)前普遍采用(yong)真空加壓(ya)(ya)浸(jin)(jin)滲(shen)法。真空加壓(ya)(ya)浸(jin)(jin)滲(shen)過程主要在(zai)真空壓(ya)(ya)力(li)罐中進行，其工藝流程如圖1所示。按工藝處(chu)(chu)理順序可分為前處(chu)(chu)理、浸(jin)(jin)滲(shen)處(chu)(chu)理和后處(chu)(chu)理3個階段。
前(qian)處(chu)理(li)是將(jiang)鑄(zhu)件脫(tuo)(tuo)脂(zhi)、清洗，再(zai)干(gan)燥備用。主要目(mu)的在于去除零件表(biao)面的油污、金屬碎屑和灰塵(chen)，提高浸(jin)滲(shen)質(zhi)量(liang)，防止(zhi)油污及(ji)機械雜質(zhi)帶入(ru)浸(jin)滲(shen)液(ye)中(zhong)影響滲(shen)透力和粘結力。常用脫(tuo)(tuo)脂(zhi)方(fang)法有溶劑脫(tuo)(tuo)脂(zhi)、堿液(ye)脫(tuo)(tuo)脂(zhi)及(ji)電化(hua)學(xue)脫(tuo)(tuo)脂(zhi)。鑄(zhu)件在上述脫(tuo)(tuo)脂(zhi)清洗后，取(qu)出經熱水(shui)漂(piao)洗再(zai)在80~90℃下烘(hong)干(gan)，為提高浸(jin)透效果(guo)，并防止(zhi)大量(liang)水(shui)分進入(ru)真空泵，清洗后的烘(hong)干(gan)是非常重(zhong)要的。
浸滲設備浸滲(shen)(shen)(shen)處理(li)是(shi)將經前(qian)處理(li)的工件(jian)裝浸滲(shen)(shen)(shen)罐密封(feng)抽真空15min，以充(chong)分排除罐內及鑄件(jian)孔隙處的空氣和(he)微塵，為浸滲(shen)(shen)(shen)劑(ji)的填充(chong)和(he)滲(shen)(shen)(shen)透創(chuang)造壓差(cha)動力條件(jian)。然后利用(yong)罐內負壓吸入浸滲(shen)(shen)(shen)劑(ji)，再次抽真空15min。
二(er)次(ci)抽(chou)真空(kong)的(de)目的(de)，在于排出罐內浸滲液中的(de)氣(qi)體，防止(zhi)溶有氣(qi)體的(de)浸滲液滲入(ru)鑄(zhu)件(jian)微孔缺點(dian)中去，以防止(zhi)固(gu)化時氣(qi)孔的(de)產生影響密(mi)封性能。較后加壓0.5~0.75MPa，保持15~20min使(shi)已(yi)充填(tian)和(he)滲入(ru)鑄(zhu)件(jian)孔隙 內 部(bu)的(de)浸滲劑進一(yi)步向缺點(dian)各(ge)個部(bu)位較深處滲透。
后處理(li)是將工件滴(di)干、清洗并放入固(gu)化(hua)爐(lu)中固(gu)化(hua)，使進(jin)入鑄件孔隙的(de)(de)浸滲劑由液態向固(gu)態轉變，形成堅(jian)實的(de)(de)固(gu)化(hua)膜。
固(gu)化溫度為(wei)80~90℃，保持2h以上(shang)，或在(zai)(zai)室溫(25℃以上(shang))下放置24h。如鑄(zhu)件(jian)在(zai)(zai)300℃以上(shang)條件(jian)使(shi)用，宜先在(zai)(zai)80℃溫度下固(gu)化2h，接(jie)著在(zai)(zai)110℃溫度下繼續(xu)固(gu)化1h。受壓(ya)鑄(zhu)件(jian)浸(jin)(jin)滲(shen)(shen)后(hou)需進(jin)行(xing)壓(ya)力試驗(yan)，檢(jian)查浸(jin)(jin)滲(shen)(shen)處(chu)(chu)理(li)后(hou)是否達到要(yao)求的氣密性。凡在(zai)(zai)浸(jin)(jin)滲(shen)(shen)范圍內仍(reng)有泄漏(lou)，允許進(jin)行(xing)再浸(jin)(jin)滲(shen)(shen)，對(dui)3次浸(jin)(jin)滲(shen)(shen)仍(reng)有泄漏(lou)的鑄(zhu)件(jian)作廢品(pin)處(chu)(chu)理(li)。通常，試驗(yan)壓(ya)力值(zhi)(zhi)為(wei)工作壓(ya)力值(zhi)(zhi)的2倍。
(二)、浸滲工藝(yi)流程和浸滲方法(fa)
1用無機硅酸鈉(水玻璃)浸滲(shen)劑浸滲(shen)
采用無機硅酸(suan)鈉(水玻璃)浸滲劑浸滲的工藝(yi)流(liu)程。
工藝(yi)步驟：加工裝(zhuang)配好閥(fa)(fa)(fa)門(men)(men)(men)，封(feng)閉閥(fa)(fa)(fa)門(men)(men)(men)2端法蘭，微(wei)開(kai)(kai)啟閥(fa)(fa)(fa)門(men)(men)(men)密封(feng)面(mian)(閘板密封(feng)圈(quan)不接觸閥(fa)(fa)(fa)座密封(feng)面(mian))，向閥(fa)(fa)(fa)門(men)(men)(men)體(ti)腔注入(ru)模(mo)數為1.5~2.0的(de)無(wu)機硅(gui)酸鈉(水(shui)玻璃)浸(jin)(jin)(jin)滲(shen)(shen)劑(ji)(ji)，注入(ru)的(de)浸(jin)(jin)(jin)滲(shen)(shen)劑(ji)(ji)液面(mian)高于密封(feng)圈(quan)上(shang)沿即可(ke)(ke)(ke)，關(guan)閉浸(jin)(jin)(jin)滲(shen)(shen)劑(ji)(ji)輸入(ru)閥(fa)(fa)(fa)，用空壓(ya)(ya)機給閥(fa)(fa)(fa)門(men)(men)(men)體(ti)腔加壓(ya)(ya)0.4一0.6MPa保持壓(ya)(ya)力(li)15min后，將閥(fa)(fa)(fa)門(men)(men)(men)體(ti)腔卸(xie)壓(ya)(ya)至零(恢(hui)復(fu)到常壓(ya)(ya))，回收閥(fa)(fa)(fa)門(men)(men)(men)體(ti)腔內浸(jin)(jin)(jin)滲(shen)(shen)劑(ji)(ji)放入(ru)浸(jin)(jin)(jin)滲(shen)(shen)劑(ji)(ji)儲罐，向閥(fa)(fa)(fa)門(men)(men)(men)體(ti)腔內吹入(ru)二碳氣體(ti)(3~5min)可(ke)(ke)(ke)使浸(jin)(jin)(jin)滲(shen)(shen)劑(ji)(ji)固(gu)化(hua)，從而(er)縮短浸(jin)(jin)(jin)滲(shen)(shen)時間(或(huo)常溫下將浸(jin)(jin)(jin)滲(shen)(shen)過的(de)閥(fa)(fa)(fa)門(men)(men)(men)放置(zhi)20~26h，讓(rang)浸(jin)(jin)(jin)滲(shen)(shen)劑(ji)(ji)自然固(gu)化(hua))，打開(kai)(kai)閥(fa)(fa)(fa)門(men)(men)(men)，清理粘(zhan)結(jie)在閥(fa)(fa)(fa)門(men)(men)(men)體(ti)腔及銅合金密封(feng)圈(quan)表面(mian)的(de)浸(jin)(jin)(jin)滲(shen)(shen)劑(ji)(ji)固(gu)化(hua)后的(de)殘余物(wu)(殘余物(wu)有(you)的(de)粘(zhan)結(jie)力(li)和強(qiang)度，需要借(jie)助工具清理)，浸(jin)(jin)(jin)滲(shen)(shen)完(wan)成。按閥(fa)(fa)(fa)門(men)(men)(men)壓(ya)(ya)力(li)試(shi)(shi)驗(yan)要求對閥(fa)(fa)(fa)門(men)(men)(men)進行壓(ya)(ya)力(li)試(shi)(shi)驗(yan)。試(shi)(shi)驗(yan)時，如還(huan)有(you)因材料微(wei)空引起的(de)滲(shen)(shen)漏，可(ke)(ke)(ke)以重復(fu)上(shang)述浸(jin)(jin)(jin)滲(shen)(shen)過程，直至閥(fa)(fa)(fa)門(men)(men)(men)壓(ya)(ya)力(li)試(shi)(shi)驗(yan)合格。
2用甲(jia)基(ji)丙(bing)烯酸脂(zhi)浸滲(shen)劑(ji)浸滲(shen)
工(gong)藝步驟：加工(gong)裝配好(hao)閥(fa)(fa)門(men)(men)(men)(men)，用(yong)(yong)除脂劑(ji)(ji)對閥(fa)(fa)門(men)(men)(men)(men)體(ti)(ti)(ti)(ti)(ti)腔(qiang)(qiang)(qiang)及(ji)銅(tong)(tong)合(he)(he)金(jin)密封(feng)(feng)圈(quan)(quan)進行除脂處理，對除脂后的(de)(de)閥(fa)(fa)門(men)(men)(men)(men)體(ti)(ti)(ti)(ti)(ti)腔(qiang)(qiang)(qiang)及(ji)銅(tong)(tong)合(he)(he)金(jin)密封(feng)(feng)圈(quan)(quan)用(yong)(yong)清水(shui)(shui)沖洗2~3min，用(yong)(yong)空(kong)壓(ya)(ya)機(ji)(ji)吹干閥(fa)(fa)門(men)(men)(men)(men)體(ti)(ti)(ti)(ti)(ti)腔(qiang)(qiang)(qiang)及(ji)銅(tong)(tong)合(he)(he)金(jin)密封(feng)(feng)圈(quan)(quan)表(biao)面(mian)的(de)(de)水(shui)(shui)，封(feng)(feng)閉閥(fa)(fa)門(men)(men)(men)(men)兩端法蘭，微開(kai)啟閥(fa)(fa)門(men)(men)(men)(men)密封(feng)(feng)面(mian)(閘(zha)板密封(feng)(feng)圈(quan)(quan)不接(jie)觸閥(fa)(fa)座密封(feng)(feng)面(mian))，用(yong)(yong)真(zhen)空(kong)泵(beng)將閥(fa)(fa)門(men)(men)(men)(men)體(ti)(ti)(ti)(ti)(ti)腔(qiang)(qiang)(qiang)抽(chou)真(zhen)空(kong)(-0.1MPa)并(bing)(bing)保壓(ya)(ya)15min向閥(fa)(fa)門(men)(men)(men)(men)體(ti)(ti)(ti)(ti)(ti)腔(qiang)(qiang)(qiang)注(zhu)入(ru)(ru)甲(jia)基丙烯酸脂浸(jin)(jin)(jin)滲(shen)(shen)劑(ji)(ji)，注(zhu)入(ru)(ru)的(de)(de)浸(jin)(jin)(jin)滲(shen)(shen)劑(ji)(ji)液面(mian)高于密封(feng)(feng)圈(quan)(quan)上沿(yan)即可，關閉浸(jin)(jin)(jin)滲(shen)(shen)劑(ji)(ji)輸入(ru)(ru)閥(fa)(fa)，再(zai)用(yong)(yong)真(zhen)空(kong)泵(beng)將閥(fa)(fa)門(men)(men)(men)(men)體(ti)(ti)(ti)(ti)(ti)腔(qiang)(qiang)(qiang)抽(chou)真(zhen)空(kong)(-0.1MPa)并(bing)(bing)保壓(ya)(ya)15min左右，將閥(fa)(fa)門(men)(men)(men)(men)體(ti)(ti)(ti)(ti)(ti)腔(qiang)(qiang)(qiang)恢復常(chang)壓(ya)(ya)至(zhi)零(ling)位，用(yong)(yong)空(kong)壓(ya)(ya)機(ji)(ji)給閥(fa)(fa)門(men)(men)(men)(men)體(ti)(ti)(ti)(ti)(ti)腔(qiang)(qiang)(qiang)加壓(ya)(ya)0.4~0.6MPa保持壓(ya)(ya)力15min后，再(zai)將閥(fa)(fa)門(men)(men)(men)(men)體(ti)(ti)(ti)(ti)(ti)腔(qiang)(qiang)(qiang)卸壓(ya)(ya)至(zhi)零(ling)位，回收閥(fa)(fa)門(men)(men)(men)(men)體(ti)(ti)(ti)(ti)(ti)腔(qiang)(qiang)(qiang)內(nei)浸(jin)(jin)(jin)滲(shen)(shen)劑(ji)(ji)放入(ru)(ru)浸(jin)(jin)(jin)滲(shen)(shen)劑(ji)(ji)儲罐，打開(kai)閥(fa)(fa)門(men)(men)(men)(men)，用(yong)(yong)清水(shui)(shui)沖洗閥(fa)(fa)門(men)(men)(men)(men)體(ti)(ti)(ti)(ti)(ti)腔(qiang)(qiang)(qiang)及(ji)銅(tong)(tong)合(he)(he)金(jin)密封(feng)(feng)圈(quan)(quan)表(biao)面(mian)3~5min給閥(fa)(fa)門(men)(men)(men)(men)體(ti)(ti)(ti)(ti)(ti)腔(qiang)(qiang)(qiang)注(zhu)入(ru)(ru)90℃~95℃的(de)(de)熱(re)水(shui)(shui)并(bing)(bing)保持20min進行固化，或將電熱(re)吹風(feng)機(ji)(ji)固定在一個能移動的(de)(de)小支(zhi)架上，對銅(tong)(tong)密封(feng)(feng)圈(quan)(quan)(浸(jin)(jin)(jin)滲(shen)(shen)表(biao)面(mian))加熱(re)(90℃~95℃，450W電熱(re)吹風(feng)機(ji)(ji)口距工(gong)件表(biao)面(mian)250~270mm)30min進行浸(jin)(jin)(jin)滲(shen)(shen)固化，浸(jin)(jin)(jin)滲(shen)(shen)完(wan)成。按閥(fa)(fa)門(men)(men)(men)(men)壓(ya)(ya)力試驗要求對閥(fa)(fa)門(men)(men)(men)(men)進行壓(ya)(ya)力試驗。