在使用過程中，大多數鐵嶺機械密封都屬于接觸式密封，其機理是靠動密封環與靜密封環的接觸端面在密封流體壓力和彈性元件壓緊力的作用下緊密貼合，并相對滑動而達到密封。工作時，鐵嶺機械密封端面上同時發生摩擦、滑動與磨損等現象，摩擦是它的基本特征。鐵嶺機械密封端面(mian)摩(mo)(mo)擦(ca)(ca)(ca)(ca)(ca)(ca)的(de)(de)(de)工況(kuang)一般分為：流(liu)體(ti)摩(mo)(mo)擦(ca)(ca)(ca)(ca)(ca)(ca)、混合摩(mo)(mo)擦(ca)(ca)(ca)(ca)(ca)(ca)和邊界摩(mo)(mo)擦(ca)(ca)(ca)(ca)(ca)(ca)三(san)類，但不能長時間干(gan)摩(mo)(mo)擦(ca)(ca)(ca)(ca)(ca)(ca)。干(gan)摩(mo)(mo)擦(ca)(ca)(ca)(ca)(ca)(ca)狀態時，兩端面(mian)間的(de)(de)(de)固體(ti)表面(mian)微凸體(ti)將(jiang)直接(jie)接(jie)觸而引起劇(ju)烈(lie)的(de)(de)(de)磨損。磨損時一方(fang)面(mian)會(hui)使摩(mo)(mo)擦(ca)(ca)(ca)(ca)(ca)(ca)表面(mian)物質喪失或遷移，導(dao)致表面(mian)損壞；另一方(fang)面(mian)會(hui)產生大量的(de)(de)(de)摩(mo)(mo)擦(ca)(ca)(ca)(ca)(ca)(ca)熱(re)直至燒毀密(mi)封(feng)。在無流(liu)體(ti)介質的(de)(de)(de)工況(kuang)下，如何(he)減少磨損降低摩(mo)(mo)擦(ca)(ca)(ca)(ca)(ca)(ca)熱(re)，那(nei)就要依靠干(gan)磨密(mi)封(feng)了。

　　干(gan)磨密(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)封(feng)(feng)(feng)(feng)(feng)(feng)(feng)(feng)屬(shu)于浮動(dong)(dong)(dong)(dong)密(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)封(feng)(feng)(feng)(feng)(feng)(feng)(feng)(feng)的(de)一種，常用(yong)材(cai)質為耐(nai)磨碳精，結構(gou)包(bao)括環(huan)(huan)行(xing)(xing)(xing)密(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)封(feng)(feng)(feng)(feng)(feng)(feng)(feng)(feng)腔體和環(huan)(huan)行(xing)(xing)(xing)軸(zhou)套(tao)，密(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)封(feng)(feng)(feng)(feng)(feng)(feng)(feng)(feng)腔體內(nei)有(you)(you)環(huan)(huan)行(xing)(xing)(xing)槽，槽內(nei)至(zhi)少裝有(you)(you)二(er)個截(jie)面(mian)(mian)為矩形的(de)環(huan)(huan)行(xing)(xing)(xing)石墨密(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)封(feng)(feng)(feng)(feng)(feng)(feng)(feng)(feng)環(huan)(huan)，石墨密(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)封(feng)(feng)(feng)(feng)(feng)(feng)(feng)(feng)環(huan)(huan)的(de)內(nei)徑與環(huan)(huan)行(xing)(xing)(xing)軸(zhou)套(tao)之間(jian)有(you)(you)0.01-0.04的(de)間(jian)隙(xi)，軸(zhou)套(tao)外表面(mian)(mian)涂(tu)有(you)(you)耐(nai)磨涂(tu)層，涂(tu)層材(cai)料(liao)一般為三(san)氧(yang)化二(er)鋁或(huo)三(san)氧(yang)化二(er)鉻。干(gan)磨密(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)封(feng)(feng)(feng)(feng)(feng)(feng)(feng)(feng)有(you)(you)時(shi)需(xu)要(yao)(yao)增加隔離氣(qi)，通(tong)常使用(yong)氮氣(qi)，氮氣(qi)耗(hao)量能控(kong)制在25-40。主(zhu)要(yao)(yao)應用(yong)于密(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)封(feng)(feng)(feng)(feng)(feng)(feng)(feng)(feng)易燃(ran)有(you)(you)毒介質，由于操作維(wei)修(xiu)簡單，密(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)封(feng)(feng)(feng)(feng)(feng)(feng)(feng)(feng)性好(hao)，不需(xu)要(yao)(yao)復雜的(de)潤(run)滑(hua)冷卻系統(tong)，可以干(gan)運(yun)行(xing)(xing)(xing)，得(de)到廣泛的(de)應用(yong)。干(gan)磨密(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)封(feng)(feng)(feng)(feng)(feng)(feng)(feng)(feng)包(bao)括有(you)(you)外罩及(ji)架(jia)設于外罩上且可呈相對旋轉及(ji)貼合(he)(he)的(de)動(dong)(dong)(dong)(dong)密(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)封(feng)(feng)(feng)(feng)(feng)(feng)(feng)(feng)環(huan)(huan)及(ji)靜密(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)封(feng)(feng)(feng)(feng)(feng)(feng)(feng)(feng)環(huan)(huan)，靜密(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)封(feng)(feng)(feng)(feng)(feng)(feng)(feng)(feng)環(huan)(huan)與外罩固(gu)定連接，靜密(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)封(feng)(feng)(feng)(feng)(feng)(feng)(feng)(feng)環(huan)(huan)及(ji)動(dong)(dong)(dong)(dong)密(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)封(feng)(feng)(feng)(feng)(feng)(feng)(feng)(feng)環(huan)(huan)上分開設有(you)(you)供旋轉軸(zhou)安裝的(de)通(tong)孔，且動(dong)(dong)(dong)(dong)密(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)封(feng)(feng)(feng)(feng)(feng)(feng)(feng)(feng)環(huan)(huan)與靜密(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)封(feng)(feng)(feng)(feng)(feng)(feng)(feng)(feng)環(huan)(huan)貼合(he)(he)的(de)端面(mian)(mian)分別為動(dong)(dong)(dong)(dong)密(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)封(feng)(feng)(feng)(feng)(feng)(feng)(feng)(feng)面(mian)(mian)及(ji)靜密(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)封(feng)(feng)(feng)(feng)(feng)(feng)(feng)(feng)面(mian)(mian)，外罩上設有(you)(you)促使動(dong)(dong)(dong)(dong)密(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)封(feng)(feng)(feng)(feng)(feng)(feng)(feng)(feng)環(huan)(huan)與靜密(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)封(feng)(feng)(feng)(feng)(feng)(feng)(feng)(feng)環(huan)(huan)緊密(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)貼合(he)(he)的(de)彈性抵壓件。除了(le)要(yao)(yao)保持密(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)(mi)封(feng)(feng)(feng)(feng)(feng)(feng)(feng)(feng)面(mian)(mian)平行(xing)(xing)(xing)之外，主(zhu)要(yao)(yao)是摩擦副的(de)材(cai)料(liao)問題(ti)。

　　摩擦材料應具(ju)備下列(lie)條件：

　　(1)機械強度高，能(neng)耐壓(ya)和耐壓(ya)力變(bian)形(xing)；

　　(2)具有耐干磨性(xing)，耐高載荷性(xing)，自(zi)潤(run)滑性(xing)好；

　　(3)配對(dui)材料的磨合性好，無(wu)過大(da)的磨損和對(dui)偶(ou)腐蝕(shi)；

　　(4)耐(nai)磨性好，摩擦材(cai)料雖(sui)然是易損(sun)件(jian)，起到保護制動(dong)或傳(chuan)動(dong)裝置的(de)作用(yong)，但要求具(ju)有一定(ding)的(de)耐(nai)磨性，使(shi)用(yong)壽命盡量要長，刮(gua)傷、腐蝕和粘附對偶(ou)，都會造(zao)成(cheng)制動(dong)或傳(chuan)動(dong)的(de)震(zhen)動(dong)和不穩(wen)定(ding)；

　　(5)導(dao)(dao)熱(re)性(xing)(xing)和散熱(re)性(xing)(xing)好，導(dao)(dao)熱(re)性(xing)(xing)是傳(chuan)導(dao)(dao)熱(re)量(liang)的(de)能力大小，即包(bao)括吸熱(re)，也(ye)(ye)包(bao)括散熱(re)，所以，導(dao)(dao)熱(re)性(xing)(xing)好的(de)必(bi)然散熱(re)性(xing)(xing)也(ye)(ye)好；

　　(6)抗(kang)熱裂(lie)性好，根本解(jie)決抗(kang)熱裂(lie)性問題可(ke)能(neng)需(xu)要改變封孔方法；

　　(7)耐(nai)腐(fu)蝕(shi)性(xing)強，一些有色金(jin)屬合金(jin)能(neng)將良好的摩擦(ca)學特(te)性(xing)與有些流(liu)體(ti)的耐(nai)腐(fu)蝕(shi)性(xing)結合；

　　(8)線膨脹(zhang)系(xi)數(shu)小，熱膨脹(zhang)會造成摩(mo)擦材料與摩(mo)擦對偶(ou)之間的間隙過小，發生拖(tuo)摩(mo)，損毀制動、傳動裝置(zhi)。