發布時間:2026-04-23 03:04:08 人氣:304360 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)理塘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。
在zai處chu理li強qiang腐fu蝕shi性xing流liu體ti時shi,采cai用yong外wai密mi封feng或huo雙shuang端duan密mi封feng可ke以yi最zui大da限xian度du地di減jian少shao腐fu蝕shi對dui密mi封feng的de影ying響xiang,因yin為wei它ta與yu工gong藝yi流liu體ti接jie觸chu的de零ling件jian數shu量liang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最zui古gu老lao的de窯yao理li之zhi一yi。
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型理塘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理塘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理塘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)就(jiu)是(shi)典(dian)型(xing)的(de)例(li)子(zi)。原(yuan)因(yin)是(shi)接(jie)頭(tou)內(nei)的(de)介(jie)質(zhi)處(chu)於(yu)停(ting)滯(zhi)狀(zhuang)態(tai),使(shi)得(de)參(can)與(yu)腐(fu)蝕(shi)反(fan)應(ying)的(de)物(wu)質(zhi)難(nan)以(yi)加(jia)入(ru)接(jie)頭(tou)內(nei),接(jie)頭(tou)內(nei)的(de)腐(fu)蝕(shi)產(chan)物(wu)難(nan)以(yi)向(xiang)外(wai)擴(kuo)散(san)。隨(sui)著(zhe)腐(fu)蝕(shi)的(de)進(jin)行(xing),接(jie)頭(tou)中(zhong)的(de)介(jie)質(zhi)在(zai)成(cheng)分(fen)濃(nong)度(du)和(he)PH值zhi上shang與yu整zheng個ge介jie質zhi越yue來lai越yue不bu同tong,導dao致zhi接jie頭tou中zhong金jin屬shu表biao麵mian的de腐fu蝕shi加jia劇ju。間jian隙xi腐fu蝕shi對dui密mi封feng性xing能neng非fei常chang有you害hai。密mi封feng圈quan與yu雙shuang軸zhou之zhi間jian的de凹ao槽cao會hui導dao致zhi補bu償chang環huan無wu法fa軸zhou向xiang位wei移yi,失shi去qu隨sui動dong性xing,導dao致zhi端duan麵mian分fen離li和he泄xie漏lou。間jian隙xi腐fu蝕shi通tong常chang可ke以yi通tong過guo適shi當dang的de材cai料liao選xuan擇ze和he合he理li的de結jie構gou設she計ji來lai緩huan解jie。比bi如ru選xuan擇ze抗kang間jian隙xi腐fu蝕shi性xing能neng好hao的de材cai料liao;zaijiegoushejizhong,yingjinkenengbimianyetijijudejianxihesiqu。caiyongzichongxixunhuan,shimifengqiangneidejiezhichuyubuduangenghuanheliudongdezhuangtai,fangzhijiezhichengfendenongdubianhua;duiyuchangqitingyongdebeng,yingjishipaichujijudeyetideng。bukenengwanquanxiaochujiegoushangdechaju。suoyiyibancaiyongfanghuzhoucheng,keyizaimifengquananzhuangbuweipentunaifushicailiaolaifangzhi。
5.電化學腐蝕。事實上,理塘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。就理塘機械密封摩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。