管(guan)道工程中(zhong)常用的(de)有色金屬(shu)(Non-ferrous Metal)有銅、鋁、鉛和鋅等。
1. 銅(Copper)
銅(tong)又分純銅(tong)(俗稱紫銅(tong))、黃銅(tong)和青銅(tong)等。有(you)關銅(tong)管的(de)標準(zhun)(zhun)規(gui)范包(bao)括 ASTM B42、ASTM B43、ASTM B315、ASTM B466、ASTM B467,有(you)關銅(tong)管件的(de)標準(zhun)(zhun)規(gui)范有(you)ASMEB16.24、ASME B16.22、ASME B16.15、ASME B16.18等。
a. 純銅(Copper)
純(chun)銅(tong)呈紫紅色,有良好(hao)的(de)導(dao)電性(xing)(xing)、導(dao)熱性(xing)(xing)和(he)耐(nai)大氣腐蝕性(xing)(xing),熔點(dian)為(wei)1083℃。在管(guan)(guan)道(dao)(dao)工程中常(chang)(chang)用(yong)(yong)純(chun)銅(tong)制(zhi)(zhi)成鋼管(guan)(guan)和(he)法蘭墊片。因純(chun)銅(tong)硬度(du)較低(di),退(tui)火(huo)后(hou)變得更(geng)柔軟(ruan),故(gu)常(chang)(chang)用(yong)(yong)來制(zhi)(zhi)作高壓(ya)管(guan)(guan)道(dao)(dao)中 的(de)法蘭墊片。純(chun)銅(tong)管(guan)(guan)的(de)低(di)溫性(xing)(xing)能(neng)比鋼材好(hao),故(gu)純(chun)銅(tong)管(guan)(guan)常(chang)(chang)用(yong)(yong)于空分設備管(guan)(guan)道(dao)(dao)、冷凍管(guan)(guan)道(dao)(dao)和(he)儀表(biao)管(guan)(guan)道(dao)(dao)。純(chun)銅(tong)的(de)高溫性(xing)(xing)能(neng)差(cha),在120℃以下(xia),允(yun)許抗(kang)拉強(qiang)度(du)為(wei)29.43MPa。溫度(du)若(ruo)再升高,其機械(xie)強(qiang)度(du)則急劇下(xia)降,當溫度(du)上升至(zhi)250℃時,其允(yun)許抗(kang)拉強(qiang)度(du)只相當于常(chang)(chang)溫時的(de)2/3,已不宜在壓(ya)力(li)下(xia)使(shi)用(yong)(yong)。
常用的純銅牌號為T2、T3、T4,雜質(zhi)含量T2最少,T4最多。
b. 黃銅(Brass)
黃銅(tong)是銅(tong)和(he)鋅的(de)(de)合金,其機械(xie)強(qiang)度(du)(du)高,有較好的(de)(de)耐腐蝕性和(he)澆鑄性,可(ke)用(yong)來制作管(guan)子、管(guan)件和(he)閥門等。化(hua)工上常用(yong)的(de)(de)有H80、H68、H62(“H”是黃銅(tong)代號,后邊的(de)(de)數字表示合金中銅(tong)的(de)(de)平均(jun)含(han)量)。H80比H68塑性好。進行強(qiang)度(du)(du)計算時(shi)(shi),在120℃以(yi)下(xia),黃銅(tong)允許(xu)抗拉強(qiang)度(du)(du)為29.43MPa。隨著溫(wen)度(du)(du)升高,其強(qiang)度(du)(du)則急(ji)劇下(xia)降,當溫(wen)度(du)(du)未超過225℃時(shi)(shi),黃銅(tong)閥件可(ke)用(yong)在壓力不超過1.6MPa的(de)(de)管(guan)道中。
c. 青銅(Bronze)
青(qing)(qing)(qing)(qing)(qing)銅(tong)(tong)是銅(tong)(tong)和(he)(he)錫(xi)(xi)的合(he)金,又(you)稱錫(xi)(xi)青(qing)(qing)(qing)(qing)(qing)銅(tong)(tong)。由于錫(xi)(xi)的價格(ge)較(jiao)高,故制(zhi)造(zao)青(qing)(qing)(qing)(qing)(qing)銅(tong)(tong)也常(chang)用其(qi)(qi)他元素代替,因而又(you)有無(wu)錫(xi)(xi)青(qing)(qing)(qing)(qing)(qing)銅(tong)(tong),如鋁青(qing)(qing)(qing)(qing)(qing)銅(tong)(tong)、鉛(qian)青(qing)(qing)(qing)(qing)(qing)銅(tong)(tong)、硅青(qing)(qing)(qing)(qing)(qing)銅(tong)(tong)等。青(qing)(qing)(qing)(qing)(qing)銅(tong)(tong)通常(chang)由澆鑄(zhu)而成(cheng),其(qi)(qi)強度(du)、硬度(du)及耐(nai)腐蝕(shi)性(xing)都(dou)比(bi)黃銅(tong)(tong)好。青(qing)(qing)(qing)(qing)(qing)銅(tong)(tong)常(chang)用于制(zhi)造(zao)蝸輪、齒(chi)輪、輪,以及管道工程(cheng)中的閥件和(he)(he)管件等。
2. 鋁(Aluminum)
鋁的(de)熔點(dian)為527℃,它具有良好的(de)導熱性(xing)和導電性(xing),強(qiang)度和硬(ying)度較(jiao)低,可塑性(xing)好。鋁容易氧化(hua)(hua),在空氣中,鋁的(de)表(biao)面能(neng)形成一層(ceng)極薄的(de)氧化(hua)(hua)鋁保護膜,防止繼續(xu)氧化(hua)(hua)。鋁合金薄板常作為壓力管道絕熱工(gong)程的(de)管子、塔、罐(guan)、換熱器、閥門(men)、法蘭以及其他平壁(bi)設備保護層(ceng)材料(liao)。
純鋁(lv)(lv)的(de)強度(du)(du)和(he)(he)硬度(du)(du)雖然很低,但若(ruo)加入(ru)其他(ta)元(yuan)素(su)可以提(ti)高(gao)。鋁(lv)(lv)合金(jin)分為鑄(zhu)造鋁(lv)(lv)合金(jin)和(he)(he)可壓(ya)迫變形(xing)的(de)鋁(lv)(lv)合金(jin)兩大(da)類。管(guan)(guan)(guan)道工程(cheng)中,常用L2和(he)(he)L3牌號的(de)鋁(lv)(lv)管(guan)(guan)(guan)輸送硝酸(suan)和(he)(he)醋(cu)酸(suan)等,但是(shi)鋁(lv)(lv)不能抵(di)抗堿性腐蝕。當溫度(du)(du)高(gao)于150℃時,鋁(lv)(lv)管(guan)(guan)(guan)不宜用于壓(ya)力(li)管(guan)(guan)(guan)道。鋁(lv)(lv)和(he)(he)鋁(lv)(lv)合金(jin)管(guan)(guan)(guan)的(de)標準規范有ASTM B241、ASTM B26、ASTM B108、ASTM B209、ASTM B210、ASTM B211、ASTM
B221、ASTMI B234、ASTM B247 以及 ASME B31.3的“附錄L-鋁合金管法蘭”。
3. 鉛(Lead)
鉛(qian)(qian)(qian)是一種(zhong)暗灰色的金(jin)屬,熔(rong)點為327℃,它有(you)很好的耐(nai)腐(fu)(fu)蝕性(xing)能,常(chang)(chang)(chang)用(yong)來制(zhi)作(zuo)硫酸設備和管(guan)(guan)(guan)道(dao)(dao)襯里。鉛(qian)(qian)(qian)質軟(ruan),可(ke)塑(su)性(xing)好,管(guan)(guan)(guan)道(dao)(dao)工程中(zhong)常(chang)(chang)(chang)用(yong)鉛(qian)(qian)(qian)管(guan)(guan)(guan)。在安(an)裝鑄鐵管(guan)(guan)(guan)承(cheng)插口(kou)時(shi),常(chang)(chang)(chang)用(yong)鉛(qian)(qian)(qian)作(zuo)為接口(kou)填(tian)塞材料,以牌號為Pb-6的鉛(qian)(qian)(qian)較(jiao)適宜。硬鉛(qian)(qian)(qian)是鉛(qian)(qian)(qian)和銻的合金(jin),它的抗腐(fu)(fu)蝕性(xing)略低于(yu)(yu)(yu)純鉛(qian)(qian)(qian),但機械強(qiang)度較(jiao)高,常(chang)(chang)(chang)用(yong)于(yu)(yu)(yu)制(zhi)造(zao)耐(nai)酸設備。鉛(qian)(qian)(qian)蒸氣(qi)有(you)毒(du),故(gu)熔(rong)化鉛(qian)(qian)(qian)時(shi),要(yao)防止燙傷和鉛(qian)(qian)(qian)中(zhong)毒(du)。在化工行業中(zhong),鉛(qian)(qian)(qian)主要(yao)用(yong)在處理硫酸的設備上。Pb-4用(yong)于(yu)(yu)(yu)設備內襯,Pb-6用(yong)于(yu)(yu)(yu)管(guan)(guan)(guan)道(dao)(dao)接頭,硬鉛(qian)(qian)(qian)可(ke)制(zhi)造(zao)硫酸工業用(yong)的泵、閥門(men)、管(guan)(guan)(guan)道(dao)(dao)等。
4. 鋅(Zinc)
鋅(xin)(xin)呈淺灰色,熔點為(wei)419℃,它(ta)有較(jiao)好的耐腐蝕性和力學性能(neng)。有些鋼管和管件為(wei)增強耐腐蝕性能(neng),常(chang)在表面(mian)鍍一層鋅(xin)(xin),如(ru)室內給水(shui)工程中常(chang)用(yong)的鍍鋅(xin)(xin)管。