發布時間:2026-04-14 21:32:16 人氣:300263 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路橋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型路橋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路橋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.間jian隙xi腐fu蝕shi。當dang介jie質zhi處chu於yu金jin屬shu與yu金jin屬shu或huo非fei金jin屬shu構gou件jian之zhi間jian,且qie存cun在zai小xiao間jian隙xi時shi,由you於yu介jie質zhi處chu於yu停ting滯zhi狀zhuang態tai,間jian隙xi內nei金jin屬shu的de腐fu蝕shi會hui加jia速su,這zhe種zhong現xian象xiang稱cheng為wei間jian隙xi腐fu蝕shi。例li如ru路橋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)PHzhishangyuzhenggejiezhiyuelaiyuebutong,daozhijietouzhongjinshubiaomiandefushijiaju。jianxifushiduimifengxingnengfeichangyouhai。mifengquanyushuangzhouzhijiandeaocaohuidaozhibuchanghuanwufazhouxiangweiyi,shiqusuidongxing,daozhiduanmianfenlihexielou。jianxifushitongchangkeyitongguoshidangdecailiaoxuanzehehelidejiegoushejilaihuanjie。biruxuanzekangjianxifushixingnenghaodecailiao;在zai結jie構gou設she計ji中zhong,應ying盡jin可ke能neng避bi免mian液ye體ti積ji聚ju的de間jian隙xi和he死si區qu。采cai用yong自zi衝chong洗xi循xun環huan,使shi密mi封feng腔qiang內nei的de介jie質zhi處chu於yu不bu斷duan更geng換huan和he流liu動dong的de狀zhuang態tai,防fang止zhi介jie質zhi成cheng分fen的de濃nong度du變bian化hua;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,路橋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。就路橋機械密封摩(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。