發布時間:2026-04-25 04:29:34 人氣:305479 來源:川工密封
1.整體腐蝕和局部腐蝕。綜合腐蝕,即與介質接觸的零件表麵發生均勻腐蝕,其特點是零件重量減輕,甚至完全腐蝕;失去力量;降低硬度。如1Cr18Ni9Ti不(bu)鏽(xiu)鋼(gang)製(zhi)成(cheng)的(de)多(duo)彈(dan)簧(huang),在(zai)稀(xi)硫(liu)酸(suan)中(zhong)使(shi)用(yong)會(hui)出(chu)現(xian)這(zhe)種(zhong)情(qing)況(kuang)。局(ju)部(bu)腐(fu)蝕(shi)可(ke)以(yi)簡(jian)單(dan)地(di)通(tong)過(guo)零(ling)件(jian)上(shang)的(de)腐(fu)蝕(shi)點(dian)和(he)孔(kong)來(lai)識(shi)別(bie)。局(ju)部(bu)腐(fu)蝕(shi)是(shi)多(duo)相(xiang)合(he)金(jin)中(zhong)的(de)某(mou)一(yi)相(xiang)或(huo)單(dan)相(xiang)固(gu)溶(rong)體(ti)中(zhong)的(de)某(mou)一(yi)元(yuan)素(su)被(bei)介(jie)質(zhi)選(xuan)擇(ze)性(xing)溶(rong)解(jie)的(de)腐(fu)蝕(shi)形(xing)式(shi)。如(ru)鈷(gu)基(ji)硬(ying)質(zhi)合(he)金(jin)在(zai)高(gao)溫(wen)強(qiang)堿(jian)條(tiao)件(jian)下(xia)使(shi)用(yong),粘(zhan)結(jie)相(xiang)金(jin)屬(shu)鈷(gu)容(rong)易(yi)被(bei)腐(fu)蝕(shi),硬(ying)質(zhi)相(xiang)碳(tan)化(hua)鎢(wu)骨(gu)架(jia)失(shi)去(qu)強(qiang)度(du),在(zai)機(ji)械(xie)力(li)的(de)作(zuo)用(yong)下(xia)導(dao)致(zhi)晶(jing)粒(li)剝(bo)落(luo)。作(zuo)為(wei)另(ling)一(yi)個(ge)例(li)子(zi),由(you)於(yu)遊(you)離(li)矽(gui)的(de)腐(fu)蝕(shi),反(fan)應(ying)燒(shao)結(jie)碳(tan)化(hua)矽(gui)的(de)表(biao)麵(mian)顯(xian)示(shi)麻(ma)點(dian)(PH>10時).
腐(fu)蝕(shi)對(dui)密(mi)封(feng)件(jian)的(de)性(xing)能(neng)有(you)很(hen)大(da)影(ying)響(xiang)。由(you)於(yu)密(mi)封(feng)比(bi)主(zhu)機(ji)的(de)零(ling)件(jian)更(geng)小(xiao),精(jing)度(du)更(geng)高(gao),所(suo)以(yi)通(tong)常(chang)選(xuan)擇(ze)比(bi)主(zhu)機(ji)密(mi)封(feng)耐(nai)腐(fu)蝕(shi)的(de)材(cai)料(liao)。對(dui)於(yu)與(yu)介(jie)質(zhi)直(zhi)接(jie)接(jie)觸(chu)的(de)密(mi)封(feng)件(jian),可(ke)參(can)考(kao)相(xiang)關(guan)腐(fu)蝕(shi)手(shou)冊(ce)中(zhong)的(de)數(shu)據(ju)選(xuan)擇(ze)合(he)適(shi)的(de)材(cai)料(liao)。然(ran)而(er),這(zhe)些(xie)數(shu)據(ju)可(ke)能(neng)與(yu)大安機械密封係統中使用的條件不一致,因為它們大多是靜態條件下的腐蝕數據,並且工藝流程中的介質包含雜質或二次化合物。經驗表明,壓力、溫度和滑動速度都會加速腐蝕。隨著溫度的升高,密封件的腐蝕速率呈指數增長。
zaichuliqiangfushixingliutishi,caiyongwaimifenghuoshuangduanmifengkeyizuidaxiandudijianshaofushiduimifengdeyingxiang,yinweitayugongyiliutijiechudelingjianshuliangzuishao。zheyeshizaiqiangfushitiaojianxiaxuanzemifengjiegouzuigulaodeyaolizhiyi。
2.應力腐蝕。應力腐蝕是金屬材料在應力作用下在腐蝕環境中的腐蝕現象。無論是外載荷還是殘餘應力,都會加劇腐蝕。奧氏體不鏽鋼、銅(tong)合(he)金(jin)等(deng)。容(rong)易(yi)產(chan)生(sheng)應(ying)力(li)腐(fu)蝕(shi)。在(zai)應(ying)力(li)腐(fu)蝕(shi)過(guo)程(cheng)中(zhong),一(yi)般(ban)在(zai)金(jin)屬(shu)表(biao)麵(mian)形(xing)成(cheng)選(xuan)擇(ze)性(xing)腐(fu)蝕(shi)槽(cao),然(ran)後(hou)繼(ji)續(xu)局(ju)部(bu)腐(fu)蝕(shi),最(zui)後(hou)在(zai)應(ying)力(li)作(zuo)用(yong)下(xia)從(cong)槽(cao)底(di)產(chan)生(sheng)裂(lie)紋(wen)。典(dian)型(xing)的(de)例(li)子(zi)是(shi)104型大安機械密封的傳動套筒,由1Cr18Ni9Ti製(zhi)成(cheng)。在(zai)氨(an)水(shui)泵(beng)中(zhong)使(shi)用(yong)時(shi),傳(chuan)動(dong)套(tao)筒(tong)的(de)傳(chuan)動(dong)耳(er)環(huan)最(zui)容(rong)易(yi)產(chan)生(sheng)應(ying)力(li)腐(fu)蝕(shi)裂(lie)紋(wen),從(cong)而(er)損(sun)壞(huai)耳(er)環(huan)。所(suo)以(yi)把(ba)凹(ao)耳(er)釘(ding)換(huan)成(cheng)實(shi)心(xin)耳(er)片(pian)可(ke)以(yi)防(fang)止(zhi)這(zhe)種(zhong)應(ying)力(li)腐(fu)蝕(shi)。
3.介jie質zhi腐fu蝕shi。密mi封feng件jian和he流liu體ti之zhi間jian的de高gao速su運yun動dong導dao致zhi接jie觸chu表biao麵mian上shang的de微wei小xiao不bu均jun勻yun。當dang流liu體ti為wei腐fu蝕shi性xing介jie質zhi時shi,會hui加jia速su密mi封feng接jie觸chu麵mian的de化hua學xue反fan應ying,有you時shi有you益yi,有you時shi有you害hai。如ru果guo形xing成cheng的de氧yang化hua層ceng被bei破po壞huai,就jiu會hui發fa生sheng腐fu蝕shi。磨mo損sun和he磨mo蝕shi交jiao替ti作zuo用yong對dui材cai料liao造zao成cheng的de損sun傷shang稱cheng為wei磨mo蝕shi。通tong常chang,磨mo損sun對dui大安機械密封的非主要部件造成的損壞,如彈簧座、推環、環(huan)座(zuo)等(deng)。並(bing)不(bu)能(neng)迅(xun)速(su)反(fan)映(ying)密(mi)封(feng)性(xing)能(neng)的(de)變(bian)化(hua),但(dan)卻(que)是(shi)摩(mo)擦(ca)副(fu)失(shi)效(xiao)的(de)主(zhu)要(yao)形(xing)式(shi)之(zhi)一(yi)。因(yin)此(ci),在(zai)腔(qiang)體(ti)的(de)腐(fu)蝕(shi)介(jie)質(zhi)中(zhong),摩(mo)擦(ca)副(fu)應(ying)由(you)耐(nai)腐(fu)蝕(shi)性(xing)好(hao)的(de)材(cai)料(liao)製(zhi)成(cheng)。例(li)如(ru),使(shi)用(yong)99.5%高純度氧化鋁陶瓷或不含遊離矽的熱壓燒結碳化矽。
4.jianxifushi。dangjiezhichuyujinshuyujinshuhuofeijinshugoujianzhijian,qiecunzaixiaojianxishi,youyujiezhichuyutingzhizhuangtai,jianxineijinshudefushihuijiasu,zhezhongxianxiangchengweijianxifushi。liru大安機械密封彈簧座與軸之間的溝槽或衝蝕點,補償環輔助密封環與軸之間的溝槽或衝蝕點(這裏當然有微動磨損)jiushidianxingdelizi。yuanyinshijietouneidejiezhichuyutingzhizhuangtai,shidecanyufushifanyingdewuzhinanyijiarujietounei,jietouneidefushichanwunanyixiangwaikuosan。suizhefushidejinxing,jietouzhongdejiezhizaichengfennongduhePHzhishangyuzhenggejiezhiyuelaiyuebutong,daozhijietouzhongjinshubiaomiandefushijiaju。jianxifushiduimifengxingnengfeichangyouhai。mifengquanyushuangzhouzhijiandeaocaohuidaozhibuchanghuanwufazhouxiangweiyi,shiqusuidongxing,daozhiduanmianfenlihexielou。jianxifushitongchangkeyitongguoshidangdecailiaoxuanzehehelidejiegoushejilaihuanjie。biruxuanzekangjianxifushixingnenghaodecailiao;在(zai)結(jie)構(gou)設(she)計(ji)中(zhong),應(ying)盡(jin)可(ke)能(neng)避(bi)免(mian)液(ye)體(ti)積(ji)聚(ju)的(de)間(jian)隙(xi)和(he)死(si)區(qu)。采(cai)用(yong)自(zi)衝(chong)洗(xi)循(xun)環(huan),使(shi)密(mi)封(feng)腔(qiang)內(nei)的(de)介(jie)質(zhi)處(chu)於(yu)不(bu)斷(duan)更(geng)換(huan)和(he)流(liu)動(dong)的(de)狀(zhuang)態(tai),防(fang)止(zhi)介(jie)質(zhi)成(cheng)分(fen)的(de)濃(nong)度(du)變(bian)化(hua);對(dui)於(yu)長(chang)期(qi)停(ting)用(yong)的(de)泵(beng),應(ying)及(ji)時(shi)排(pai)出(chu)積(ji)聚(ju)的(de)液(ye)體(ti)等(deng)。不(bu)可(ke)能(neng)完(wan)全(quan)消(xiao)除(chu)結(jie)構(gou)上(shang)的(de)差(cha)距(ju)。所(suo)以(yi)一(yi)般(ban)采(cai)用(yong)防(fang)護(hu)軸(zhou)承(cheng),可(ke)以(yi)在(zai)密(mi)封(feng)圈(quan)安(an)裝(zhuang)部(bu)位(wei)噴(pen)塗(tu)耐(nai)腐(fu)蝕(shi)材(cai)料(liao)來(lai)防(fang)止(zhi)。
5.電化學腐蝕。事實上,大安機械密封的各種腐蝕形式或多或少都與銅的電化學腐蝕有關。就大安機械密封摩(mo)擦(ca)副(fu)而(er)言(yan),它(ta)們(men)經(jing)常(chang)受(shou)到(dao)電(dian)化(hua)學(xue)腐(fu)蝕(shi)的(de)損(sun)害(hai),因(yin)為(wei)摩(mo)擦(ca)副(fu)中(zhong)通(tong)常(chang)使(shi)用(yong)不(bu)同(tong)的(de)材(cai)料(liao)。當(dang)它(ta)們(men)處(chu)於(yu)電(dian)解(jie)質(zhi)溶(rong)液(ye)中(zhong)時(shi),不(bu)同(tong)材(cai)料(liao)接(jie)觸(chu)時(shi)會(hui)出(chu)現(xian)點(dian)耦(ou)合(he)效(xiao)應(ying),即(ji)一(yi)種(zhong)材(cai)料(liao)的(de)腐(fu)蝕(shi)得(de)到(dao)促(cu)進(jin),另(ling)一(yi)種(zhong)材(cai)料(liao)的(de)腐(fu)蝕(shi)得(de)到(dao)抑(yi)製(zhi)。例(li)如(ru),當(dang)銅(tong)和(he)鎳(nie)鉻(ge)鋼(gang)用(yong)於(yu)氧(yang)化(hua)介(jie)質(zhi)時(shi),鎳(nie)鎘(ge)鋼(gang)被(bei)電(dian)離(li)和(he)分(fen)解(jie)。鹽(yan)水(shui)、海水、稀鹽酸、稀硫酸等。都是典型的電解質溶液,密封件容易發生電化學腐蝕。所以最好選擇材料或者電位相近的陶瓷,以及玻璃纖維填充的PTFE。