發布時間:2026-04-24 06:26:15 人氣:227617 來源:
腐蝕對密封件的性能影響很大。由於密封件比主機的零件小,而且更精密,通常要選用比主機封耐腐蝕的材料。
類型1.全麵腐蝕與局部腐蝕。
全麵腐蝕,即零件接觸介質的表麵產生均勻腐蝕,其特征是零件的重量減輕,甚至會全部被腐蝕;失去強度;減低硬度。如用1Cr18Ni9Ti不鏽鋼製作的多彈簧,用於稀硫酸時就會出現這種情況。局部腐蝕,可以簡單地用零件上的蝕斑、shikonglaipanming。jubufushishiduoxianghejinzhongdemouyixianghuodanxianggurongtidemouyiyuansu,beijiezhixuanzexingrongjiedefushixingtai。liru,gujiyingzhihejinyongyugaowenqiangjianzhongshi,zhanjiexiangjinshuguyibeifushi,yingzhixiangtanhuawugujiashiquqiangdu,zaijixielidezuoyongxiachanshengjingliboluo。youru,fanyingshaojietanhuagui,yinyouliguibeifushierbiaomianchengxianmadian(PH>10時)。
處(chu)理(li)強(qiang)腐(fu)蝕(shi)流(liu)體(ti)時(shi),采(cai)用(yong)外(wai)裝(zhuang)式(shi)或(huo)雙(shuang)端(duan)麵(mian)密(mi)封(feng),可(ke)以(yi)最(zui)大(da)限(xian)度(du)減(jian)輕(qing)腐(fu)蝕(shi)對(dui)密(mi)封(feng)件(jian)的(de)影(ying)響(xiang),因(yin)為(wei)它(ta)與(yu)工(gong)藝(yi)流(liu)體(ti)相(xiang)接(jie)觸(chu)的(de)零(ling)件(jian)數(shu)最(zui)少(shao)。這(zhe)也(ye)是(shi)在(zai)強(qiang)腐(fu)蝕(shi)條(tiao)件(jian)下(xia),選(xuan)擇(ze)密(mi)封(feng)結(jie)構(gou)的(de)一(yi)條(tiao)最(zui)中(zhong)古(gu)窯(yao)的(de)原(yuan)則(ze)。
類型2.應力腐蝕。
應(ying)力(li)腐(fu)蝕(shi)是(shi)金(jin)屬(shu)材(cai)料(liao)在(zai)承(cheng)受(shou)應(ying)力(li)狀(zhuang)態(tai)下(xia)處(chu)於(yu)腐(fu)蝕(shi)環(huan)境(jing)中(zhong)所(suo)產(chan)生(sheng)的(de)腐(fu)蝕(shi)現(xian)象(xiang)。不(bu)論(lun)是(shi)外(wai)部(bu)載(zai)荷(he)或(huo)殘(can)餘(yu)應(ying)力(li),腐(fu)蝕(shi)都(dou)會(hui)加(jia)劇(ju)。容(rong)易(yi)產(chan)生(sheng)應(ying)力(li)腐(fu)蝕(shi)的(de)材(cai)料(liao)的(de)奧(ao)氏(shi)體(ti)不(bu)鏽(xiu)鋼(gang)、銅tong合he金jin等deng。應ying力li腐fu蝕shi的de過guo程cheng一yi般ban是shi在zai金jin屬shu表biao麵mian上shang形xing成cheng選xuan擇ze性xing的de腐fu蝕shi溝gou槽cao,再zai繼ji續xu產chan生sheng局ju部bu腐fu蝕shi,最zui後hou在zai應ying力li的de作zuo用yong下xia,從cong溝gou槽cao底di部bu產chan生sheng裂lie紋wen。典dian型xing的de實shi例li是shi104型盱眙機械密封的傳動套,它的材料為1Cr18Ni9Ti,當(dang)用(yong)於(yu)氨(an)水(shui)泵(beng)上(shang)時(shi),傳(chuan)動(dong)套(tao)的(de)傳(chuan)動(dong)耳(er)環(huan)最(zui)容(rong)易(yi)出(chu)現(xian)應(ying)力(li)腐(fu)蝕(shi)裂(lie)紋(wen),使(shi)耳(er)環(huan)損(sun)壞(huai)。為(wei)此(ci),將(jiang)其(qi)凹(ao)形(xing)耳(er)環(huan)改(gai)為(wei)實(shi)心(xin)凸(tu)耳(er),即(ji)可(ke)防(fang)止(zhi)產(chan)生(sheng)這(zhe)種(zhong)應(ying)力(li)腐(fu)蝕(shi)。

類型3.介質腐蝕。
mifengjianyuliutijiandegaosuyundong,zhishijiechumianshangfashengweiguanaotubuping。dangliutiweifushixingjiezhishi,jiangjiakuaimifengjiechubiaomiandehuaxuefanying,zhezhongfanyingyoushishiyoulide,youshishiyouhaide。ruguosuoxingchengdeyanghuacengbeipohuai,jichuxianfushi。youmosunyumoshidejiaotizuoyongerzaochengcailiaodepohuaichengweimoshi。tongchangmoshidui盱眙機械密封的非主要元件如彈簧座、推環、環(huan)座(zuo)等(deng)所(suo)帶(dai)來(lai)的(de)危(wei)害(hai)還(hai)不(bu)致(zhi)迅(xun)速(su)地(di)反(fan)應(ying)出(chu)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)態(tai)之(zhi)一(yi)。為(wei)此(ci),在(zai)腔(qiang)腐(fu)蝕(shi)性(xing)介(jie)質(zhi)中(zhong),摩(mo)擦(ca)副(fu)應(ying)采(cai)用(yong)耐(nai)腐(fu)蝕(shi)性(xing)能(neng)好(hao)的(de)材(cai)料(liao)。如(ru)采(cai)用(yong)99.5%的高純氧化鋁陶瓷,或不含遊離矽的熱壓燒結碳化矽等。
類型4.間隙腐蝕。
dangjiezhichuyujinshuyujinshuhuifeijinshuyuanjianzhijian,cunzaihenxiaodefengxishi,youyujiezhichengzhiliuzhuangtai,huiyinqifengxineijinshudefushijiasu,zhezhongfushixingtaichengweijianxifushi。liru盱眙機械密封彈簧座與軸之間,補償環輔助密封圈與軸之間(當然此處還存在微動磨損)出chu現xian的de溝gou槽cao或huo蝕shi點dian即ji是shi典dian型xing的de例li子zi。究jiu其qi原yuan因yin,是shi由you於yu縫feng內nei介jie質zhi處chu於yu滯zhi流liu狀zhuang態tai,使shi得de參can加jia腐fu蝕shi反fan應ying的de物wu質zhi難nan以yi向xiang縫feng內nei補bu充chong,而er縫feng內nei的de腐fu蝕shi產chan物wu又you難nan以yi向xiang外wai擴kuo散san,於yu是shi造zao成cheng縫feng內nei介jie質zhi隨sui著zhe腐fu蝕shi的de進jin行xing,在zai組zu成cheng的de濃nong度du、PH值等方麵愈來愈和整體介質產生很大差異,結果便導致縫內金屬表麵的腐蝕加劇。
間(jian)隙(xi)腐(fu)蝕(shi)對(dui)密(mi)封(feng)性(xing)能(neng)的(de)危(wei)害(hai)很(hen)大(da),密(mi)封(feng)圈(quan)與(yu)對(dui)偶(ou)軸(zhou)處(chu)產(chan)生(sheng)溝(gou)槽(cao),將(jiang)導(dao)致(zhi)補(bu)償(chang)環(huan)不(bu)能(neng)作(zuo)軸(zhou)向(xiang)位(wei)移(yi),失(shi)去(qu)追(zhui)隨(sui)性(xing)使(shi)端(duan)麵(mian)分(fen)離(li)而(er)泄(xie)漏(lou)。對(dui)於(yu)間(jian)隙(xi)腐(fu)蝕(shi),通(tong)常(chang)可(ke)以(yi)通(tong)過(guo)正(zheng)確(que)選(xuan)材(cai)和(he)合(he)理(li)的(de)結(jie)構(gou)設(she)計(ji)予(yu)以(yi)減(jian)輕(qing)。如(ru)選(xuan)用(yong)具(ju)有(you)良(liang)好(hao)的(de)抗(kang)間(jian)隙(xi)腐(fu)蝕(shi)性(xing)能(neng)的(de)材(cai)料(liao);在結構設計上應盡可能避免形成縫隙和積液死區;采用自衝洗方式進行循環,使密封腔內的介質處於不斷更換和流動狀態,防止介質組分的濃度變化;changqitingyongdejibeng,yingjiangjiyejishipaikongdengdeng,zaijiegoushangyaowanquanxiaochujianxishibukenengde,yinci,yibancaiyongbaohuxingdezhoucheng,zaiqimifengquananzhuangbuweikepentunaifushicailiaojiayifangzhi。
類型5.電化學腐蝕。
實際上,盱眙機械密封的各種腐蝕形態,或多或少都銅電化學腐蝕有關。就盱眙機械密封mocafueryan,changchanghuishoudaodianhuaxuefushideweihai,yinweimocafuzuduichangyongbutongzhongcailiao,dangtamenchuyudianjiezhirongyezhong,youyucailiaoguyoudefushidianweibutong,jiechushijiuhuichuchuxianbutongcailiaozhijiandedianouxiaoying,jiyizhongcailiaodefushihuishoudaocujin,lingyizhongcailiaodefushihuishoudaoyizhi。lirutongyuniegegangzudui,yongyuyanghuaxingjiezhizhongshi,niegegangfashengdianlifenjie。yanshui、海水、稀鹽酸、稀硫酸等都是典型電解質溶液,密封件易於產生電化學腐蝕,因而最好是選擇電位相近的材料或陶瓷與填充玻璃纖維聚四氟乙烯組對。