發布時間:2026-04-21 07:29:51 人氣:303545 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穆棱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shi104型穆棱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穆棱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yong99.5%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穆棱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hePH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;對dui於yu長chang期qi停ting用yong的de泵beng,應ying及ji時shi排pai出chu積ji聚ju的de液ye體ti等deng。不bu可ke能neng完wan全quan消xiao除chu結jie構gou上shang的de差cha距ju。所suo以yi一yi般ban采cai用yong防fang護hu軸zhou承cheng,可ke以yi在zai密mi封feng圈quan安an裝zhuang部bu位wei噴pen塗tu耐nai腐fu蝕shi材cai料liao來lai防fang止zhi。
5.電化學腐蝕。事實上,穆棱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。就穆棱機械密封摩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。