發布時間:2026-04-21 16:34:23 人氣:226163 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型平陸機械密封的傳動套,它的材料為1Cr18Ni9Ti,dangyongyuanshuibengshangshi,chuandongtaodechuandongerhuanzuirongyichuxianyinglifushiliewen,shierhuansunhuai。weici,jiangqiaoxingerhuangaiweishixintuer,jikefangzhichanshengzhezhongyinglifushi。

類型3.介質腐蝕。
mifengjianyuliutijiandegaosuyundong,zhishijiechumianshangfashengweiguanaotubuping。dangliutiweifushixingjiezhishi,jiangjiakuaimifengjiechubiaomiandehuaxuefanying,zhezhongfanyingyoushishiyoulide,youshishiyouhaide。ruguosuoxingchengdeyanghuacengbeipohuai,jichuxianfushi。youmosunyumoshidejiaotizuoyongerzaochengcailiaodepohuaichengweimoshi。tongchangmoshidui平陸機械密封的非主要元件如彈簧座、推環、huanzuodengsuodailaideweihaihaibuzhixunsudifanyingchumifengxingnengdebianhua,danqueshimocafushixiaodezhuyaoxingtaizhiyi。weici,zaiqiangfushixingjiezhizhong,mocafuyingcaiyongnaifushixingnenghaodecailiao。rucaiyong99.5%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平陸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;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,平陸機械密封的各種腐蝕形態,或多或少都銅電化學腐蝕有關。就平陸機械密封摩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。