管道(dao)工程中常(chang)用的(de)有色金屬(Non-ferrous Metal)有銅、鋁、鉛和鋅(xin)等。
1. 銅(Copper)
銅(tong)(tong)又(you)分(fen)純銅(tong)(tong)(俗稱紫銅(tong)(tong))、黃銅(tong)(tong)和青銅(tong)(tong)等。有關銅(tong)(tong)管的標(biao)準規(gui)范包括 ASTM B42、ASTM B43、ASTM B315、ASTM B466、ASTM B467,有關銅(tong)(tong)管件的標(biao)準規(gui)范有ASMEB16.24、ASME B16.22、ASME B16.15、ASME B16.18等。
a. 純銅(tong)(Copper)
純(chun)銅(tong)呈紫紅色,有(you)良好的(de)(de)(de)導(dao)電性(xing)、導(dao)熱性(xing)和耐大氣腐蝕性(xing),熔點(dian)為(wei)1083℃。在管(guan)(guan)(guan)道(dao)工程中常(chang)用(yong)純(chun)銅(tong)制(zhi)成(cheng)鋼管(guan)(guan)(guan)和法(fa)蘭(lan)墊(dian)片。因(yin)純(chun)銅(tong)硬度(du)(du)較低(di),退火(huo)后變得更柔軟,故(gu)常(chang)用(yong)來制(zhi)作高壓(ya)管(guan)(guan)(guan)道(dao)中 的(de)(de)(de)法(fa)蘭(lan)墊(dian)片。純(chun)銅(tong)管(guan)(guan)(guan)的(de)(de)(de)低(di)溫性(xing)能比鋼材好,故(gu)純(chun)銅(tong)管(guan)(guan)(guan)常(chang)用(yong)于(yu)空分設備(bei)管(guan)(guan)(guan)道(dao)、冷凍管(guan)(guan)(guan)道(dao)和儀表(biao)管(guan)(guan)(guan)道(dao)。純(chun)銅(tong)的(de)(de)(de)高溫性(xing)能差,在120℃以下,允許抗拉強(qiang)度(du)(du)為(wei)29.43MPa。溫度(du)(du)若再升高,其(qi)機械強(qiang)度(du)(du)則急劇下降,當溫度(du)(du)上升至(zhi)250℃時,其(qi)允許抗拉強(qiang)度(du)(du)只相(xiang)當于(yu)常(chang)溫時的(de)(de)(de)2/3,已不宜在壓(ya)力(li)下使(shi)用(yong)。
常用的純銅牌號為(wei)T2、T3、T4,雜(za)質含量T2最(zui)少,T4最(zui)多。
b. 黃銅(tong)(Brass)
黃銅是銅和鋅的(de)合(he)金,其機械(xie)強(qiang)度(du)高,有較好的(de)耐(nai)腐蝕(shi)性和澆鑄性,可(ke)用(yong)來制作管子(zi)、管件(jian)和閥(fa)門等。化工(gong)上常用(yong)的(de)有H80、H68、H62(“H”是黃銅代號,后邊的(de)數字表示(shi)合(he)金中銅的(de)平均含量(liang))。H80比(bi)H68塑性好。進行強(qiang)度(du)計算時,在120℃以下,黃銅允許抗拉強(qiang)度(du)為29.43MPa。隨著溫度(du)升高,其強(qiang)度(du)則急劇下降,當溫度(du)未超(chao)過225℃時,黃銅閥(fa)件(jian)可(ke)用(yong)在壓力不超(chao)過1.6MPa的(de)管道中。
c. 青銅(Bronze)
青(qing)(qing)(qing)銅(tong)(tong)(tong)(tong)是銅(tong)(tong)(tong)(tong)和錫(xi)的(de)(de)合金,又稱錫(xi)青(qing)(qing)(qing)銅(tong)(tong)(tong)(tong)。由于(yu)錫(xi)的(de)(de)價格較高,故制造(zao)青(qing)(qing)(qing)銅(tong)(tong)(tong)(tong)也(ye)常(chang)用其他元(yuan)素代(dai)替,因而又有無錫(xi)青(qing)(qing)(qing)銅(tong)(tong)(tong)(tong),如(ru)鋁青(qing)(qing)(qing)銅(tong)(tong)(tong)(tong)、鉛青(qing)(qing)(qing)銅(tong)(tong)(tong)(tong)、硅(gui)青(qing)(qing)(qing)銅(tong)(tong)(tong)(tong)等。青(qing)(qing)(qing)銅(tong)(tong)(tong)(tong)通常(chang)由澆鑄而成,其強(qiang)度(du)、硬度(du)及耐腐(fu)蝕性都(dou)比黃銅(tong)(tong)(tong)(tong)好。青(qing)(qing)(qing)銅(tong)(tong)(tong)(tong)常(chang)用于(yu)制造(zao)蝸輪(lun)、齒輪(lun)、輪(lun),以(yi)及管道工程中的(de)(de)閥(fa)件(jian)和管件(jian)等。
2. 鋁(Aluminum)
鋁(lv)(lv)的(de)熔點為527℃,它具有良好的(de)導熱(re)性(xing)(xing)和導電性(xing)(xing),強度(du)和硬(ying)度(du)較低,可(ke)塑性(xing)(xing)好。鋁(lv)(lv)容易氧化(hua),在空氣中(zhong),鋁(lv)(lv)的(de)表面能形成一(yi)層極薄的(de)氧化(hua)鋁(lv)(lv)保護膜,防止繼續(xu)氧化(hua)。鋁(lv)(lv)合金薄板常作為壓力管道絕熱(re)工程的(de)管子、塔、罐、換(huan)熱(re)器、閥門、法蘭以及其他平壁設備保護層材料(liao)。
純鋁(lv)的強度和硬(ying)度雖然(ran)很低,但(dan)若加入其他元素可(ke)以提高。鋁(lv)合金(jin)(jin)分為鑄造鋁(lv)合金(jin)(jin)和可(ke)壓(ya)迫變(bian)形的鋁(lv)合金(jin)(jin)兩大類。管(guan)道(dao)工程中,常用(yong)L2和L3牌(pai)號的鋁(lv)管(guan)輸送硝酸(suan)和醋(cu)酸(suan)等,但(dan)是鋁(lv)不能抵抗堿性腐蝕。當溫度高于150℃時,鋁(lv)管(guan)不宜用(yong)于壓(ya)力(li)管(guan)道(dao)。鋁(lv)和鋁(lv)合金(jin)(jin)管(guan)的標準規范(fan)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(de)“附錄L-鋁合金(jin)管(guan)法(fa)蘭(lan)”。
3. 鉛(Lead)
鉛(qian)是(shi)一種(zhong)暗灰(hui)色的(de)金(jin)屬,熔點(dian)為(wei)(wei)327℃,它有很好(hao)的(de)耐腐(fu)蝕性能(neng),常(chang)(chang)用(yong)(yong)(yong)來(lai)制(zhi)(zhi)作硫酸設(she)備(bei)和(he)管(guan)道襯里。鉛(qian)質(zhi)軟,可塑性好(hao),管(guan)道工程(cheng)中(zhong)常(chang)(chang)用(yong)(yong)(yong)鉛(qian)管(guan)。在安裝鑄(zhu)鐵管(guan)承插口(kou)時,常(chang)(chang)用(yong)(yong)(yong)鉛(qian)作為(wei)(wei)接口(kou)填(tian)塞(sai)材料,以(yi)牌號為(wei)(wei)Pb-6的(de)鉛(qian)較適宜(yi)。硬鉛(qian)是(shi)鉛(qian)和(he)銻的(de)合金(jin),它的(de)抗腐(fu)蝕性略低于(yu)(yu)純鉛(qian),但機械(xie)強度較高,常(chang)(chang)用(yong)(yong)(yong)于(yu)(yu)制(zhi)(zhi)造耐酸設(she)備(bei)。鉛(qian)蒸氣有毒,故熔化(hua)(hua)鉛(qian)時,要防止燙(tang)傷和(he)鉛(qian)中(zhong)毒。在化(hua)(hua)工行業(ye)中(zhong),鉛(qian)主要用(yong)(yong)(yong)在處理硫酸的(de)設(she)備(bei)上。Pb-4用(yong)(yong)(yong)于(yu)(yu)設(she)備(bei)內襯,Pb-6用(yong)(yong)(yong)于(yu)(yu)管(guan)道接頭(tou),硬鉛(qian)可制(zhi)(zhi)造硫酸工業(ye)用(yong)(yong)(yong)的(de)泵、閥門、管(guan)道等。
4. 鋅(Zinc)
鋅呈(cheng)淺(qian)灰色,熔點為(wei)419℃,它有較好(hao)的(de)耐(nai)腐蝕(shi)性(xing)(xing)和(he)力學性(xing)(xing)能。有些鋼管(guan)和(he)管(guan)件為(wei)增強耐(nai)腐蝕(shi)性(xing)(xing)能,常在表面鍍(du)一層鋅,如室內(nei)給水工(gong)程中常用的(de)鍍(du)鋅管(guan)。

