發布時間:2026-04-22 03:33:54 人氣:226448 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、蝕shi孔kong來lai判pan明ming。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態tai。例li如ru,鈷gu基ji硬ying質zhi合he金jin用yong於yu高gao溫wen強qiang堿jian中zhong時shi,粘zhan結jie相xiang金jin屬shu鈷gu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產chan生sheng晶jing粒li剝bo落luo。又you如ru,反fan應ying燒shao結jie碳tan化hua矽gui,因yin遊you離li矽gui被bei腐fu蝕shi而er表biao麵mian呈cheng現xian麻ma點dian(PH>10時)。
chuliqiangfushiliutishi,caiyongwaizhuangshihuoshuangduanmianmifeng,keyizuidaxiandujianqingfushiduimifengjiandeyingxiang,yinweitayugongyiliutixiangjiechudelingjianshuzuishao。zheyeshizaiqiangfushitiaojianxia,xuanzemifengjiegoudeyitiaozuizhongguyaodeyuanze。
類型2.應力腐蝕。
yinglifushishijinshucailiaozaichengshouyinglizhuangtaixiachuyufushihuanjingzhongsuochanshengdefushixianxiang。bulunshiwaibuzaihehuocanyuyingli,fushidouhuijiaju。rongyichanshengyinglifushidecailiaodeaoshitibuxiugang、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型阜平機械密封的傳動套,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。
密(mi)封(feng)件(jian)與(yu)流(liu)體(ti)間(jian)的(de)高(gao)速(su)運(yun)動(dong),致(zhi)使(shi)接(jie)觸(chu)麵(mian)上(shang)發(fa)生(sheng)微(wei)觀(guan)凹(ao)凸(tu)不(bu)平(ping)。當(dang)流(liu)體(ti)為(wei)腐(fu)蝕(shi)性(xing)介(jie)質(zhi)時(shi),將(jiang)加(jia)快(kuai)密(mi)封(feng)接(jie)觸(chu)表(biao)麵(mian)的(de)化(hua)學(xue)反(fan)應(ying),這(zhe)種(zhong)反(fan)應(ying)有(you)時(shi)是(shi)有(you)利(li)的(de),有(you)時(shi)是(shi)有(you)害(hai)的(de)。如(ru)果(guo)所(suo)形(xing)成(cheng)的(de)氧(yang)化(hua)層(ceng)被(bei)破(po)壞(huai),即(ji)出(chu)現(xian)腐(fu)蝕(shi)。由(you)磨(mo)損(sun)與(yu)磨(mo)蝕(shi)的(de)交(jiao)替(ti)作(zuo)用(yong)而(er)造(zao)成(cheng)材(cai)料(liao)的(de)破(po)壞(huai)稱(cheng)為(wei)磨(mo)蝕(shi)。通(tong)常(chang)磨(mo)蝕(shi)對(dui)阜平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阜平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)chuxiandegoucaohuoshidianjishidianxingdelizi。jiuqiyuanyin,shiyouyufengneijiezhichuyuzhiliuzhuangtai,shidecanjiafushifanyingdewuzhinanyixiangfengneibuchong,erfengneidefushichanwuyounanyixiangwaikuosan,yushizaochengfengneijiezhisuizhefushidejinxing,zaizuchengdenongdu、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;長chang期qi停ting用yong的de機ji泵beng,應ying將jiang積ji液ye及ji時shi排pai空kong等deng等deng,在zai結jie構gou上shang要yao完wan全quan消xiao除chu間jian隙xi是shi不bu可ke能neng的de,因yin此ci,一yi般ban采cai用yong保bao護hu性xing的de軸zhou承cheng,在zai其qi密mi封feng圈quan安an裝zhuang部bu位wei可ke噴pen塗tu耐nai腐fu蝕shi材cai料liao加jia以yi防fang止zhi。
類型5.電化學腐蝕。
實際上,阜平機械密封的各種腐蝕形態,或多或少都銅電化學腐蝕有關。就阜平機械密封摩(mo)擦(ca)副(fu)而(er)言(yan),常(chang)常(chang)會(hui)受(shou)到(dao)電(dian)化(hua)學(xue)腐(fu)蝕(shi)的(de)危(wei)害(hai),因(yin)為(wei)摩(mo)擦(ca)副(fu)組(zu)對(dui)常(chang)用(yong)不(bu)同(tong)種(zhong)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),由(you)於(yu)材(cai)料(liao)固(gu)有(you)的(de)腐(fu)蝕(shi)電(dian)位(wei)不(bu)同(tong),接(jie)觸(chu)時(shi)就(jiu)會(hui)出(chu)出(chu)現(xian)不(bu)同(tong)材(cai)料(liao)之(zhi)間(jian)的(de)點(dian)偶(ou)效(xiao)應(ying),即(ji)一(yi)種(zhong)材(cai)料(liao)的(de)腐(fu)蝕(shi)會(hui)受(shou)到(dao)促(cu)進(jin),另(ling)一(yi)種(zhong)材(cai)料(liao)的(de)腐(fu)蝕(shi)會(hui)受(shou)到(dao)抑(yi)製(zhi)。例(li)如(ru)銅(tong)與(yu)鎳(nie)鉻(ge)鋼(gang)組(zu)對(dui),用(yong)於(yu)氧(yang)化(hua)性(xing)介(jie)質(zhi)中(zhong)時(shi),鎳(nie)鎘(ge)鋼(gang)發(fa)生(sheng)電(dian)離(li)分(fen)解(jie)。鹽(yan)水(shui)、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。