發布時間:2026-04-20 11:46:44 人氣:225739 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、tonghejindeng。yinglifushideguochengyibanshizaijinshubiaomianshangxingchengxuanzexingdefushigoucao,zaijixuchanshengjubufushi,zuihouzaiyinglidezuoyongxia,conggoucaodibuchanshengliewen。dianxingdeshilishi104型富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)富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yong99.5%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。
當dang介jie質zhi處chu於yu金jin屬shu與yu金jin屬shu會hui非fei金jin屬shu元yuan件jian之zhi間jian,存cun在zai很hen小xiao的de縫feng隙xi時shi,由you於yu介jie質zhi呈cheng滯zhi流liu狀zhuang態tai,會hui引yin起qi縫feng隙xi內nei金jin屬shu的de腐fu蝕shi加jia速su,這zhe種zhong腐fu蝕shi形xing態tai稱cheng為wei間jian隙xi腐fu蝕shi。例li如ru富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。
jianxifushiduimifengxingnengdeweihaihenda,mifengquanyuduiouzhouchuchanshenggoucao,jiangdaozhibuchanghuanbunengzuozhouxiangweiyi,shiquzhuisuixingshiduanmianfenlierxielou。duiyujianxifushi,tongchangkeyitongguozhengquexuancaihehelidejiegoushejiyuyijianqing。ruxuanyongjuyoulianghaodekangjianxifushixingnengdecailiao;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,富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。就富平機械密封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。