管道工程中常用的有色(se)金屬(Non-ferrous Metal)有銅(tong)、鋁、鉛和鋅等。
1. 銅(Copper)
銅(tong)(tong)又分純銅(tong)(tong)(俗稱紫(zi)銅(tong)(tong))、黃銅(tong)(tong)和青銅(tong)(tong)等(deng)。有(you)關(guan)銅(tong)(tong)管的標準規范(fan)包括 ASTM B42、ASTM B43、ASTM B315、ASTM B466、ASTM B467,有(you)關(guan)銅(tong)(tong)管件的標準規范(fan)有(you)ASMEB16.24、ASME B16.22、ASME B16.15、ASME B16.18等(deng)。
a. 純銅(Copper)
純(chun)銅(tong)呈(cheng)紫(zi)紅色,有(you)良好(hao)的(de)(de)導(dao)電(dian)性(xing)、導(dao)熱性(xing)和(he)耐大氣腐蝕性(xing),熔點為1083℃。在(zai)管(guan)(guan)道工(gong)程(cheng)中(zhong)常(chang)用純(chun)銅(tong)制(zhi)成鋼(gang)管(guan)(guan)和(he)法(fa)蘭墊(dian)片。因純(chun)銅(tong)硬度(du)較低,退火(huo)后(hou)變得更柔軟(ruan),故常(chang)用來制(zhi)作高壓(ya)管(guan)(guan)道中(zhong) 的(de)(de)法(fa)蘭墊(dian)片。純(chun)銅(tong)管(guan)(guan)的(de)(de)低溫(wen)(wen)性(xing)能比鋼(gang)材(cai)好(hao),故純(chun)銅(tong)管(guan)(guan)常(chang)用于空分設(she)備管(guan)(guan)道、冷凍(dong)管(guan)(guan)道和(he)儀表管(guan)(guan)道。純(chun)銅(tong)的(de)(de)高溫(wen)(wen)性(xing)能差,在(zai)120℃以(yi)下,允許抗拉(la)強度(du)為29.43MPa。溫(wen)(wen)度(du)若再升(sheng)高,其(qi)機械強度(du)則急(ji)劇下降(jiang),當(dang)溫(wen)(wen)度(du)上升(sheng)至(zhi)250℃時(shi),其(qi)允許抗拉(la)強度(du)只相當(dang)于常(chang)溫(wen)(wen)時(shi)的(de)(de)2/3,已不(bu)宜在(zai)壓(ya)力下使(shi)用。
常用的純銅牌(pai)號為(wei)T2、T3、T4,雜質含量T2最少(shao),T4最多。
b. 黃銅(Brass)
黃銅(tong)是銅(tong)和(he)(he)鋅的(de)合金,其機械(xie)強度高(gao),有較好(hao)的(de)耐腐蝕性(xing)和(he)(he)澆鑄(zhu)性(xing),可用(yong)來制(zhi)作(zuo)管(guan)子、管(guan)件和(he)(he)閥門等(deng)。化(hua)工上常(chang)用(yong)的(de)有H80、H68、H62(“H”是黃銅(tong)代號,后(hou)邊的(de)數字(zi)表示合金中銅(tong)的(de)平均含量(liang))。H80比H68塑性(xing)好(hao)。進行強度計算(suan)時(shi),在(zai)120℃以(yi)下,黃銅(tong)允許(xu)抗(kang)拉強度為29.43MPa。隨著溫度升高(gao),其強度則急劇(ju)下降,當溫度未(wei)超過(guo)225℃時(shi),黃銅(tong)閥件可用(yong)在(zai)壓力(li)不(bu)超過(guo)1.6MPa的(de)管(guan)道中。
c. 青銅(Bronze)
青銅(tong)(tong)是銅(tong)(tong)和(he)錫的合(he)金,又稱錫青銅(tong)(tong)。由(you)于(yu)錫的價(jia)格較高,故制造青銅(tong)(tong)也常(chang)用(yong)其他元素代替(ti),因而又有(you)無錫青銅(tong)(tong),如(ru)鋁青銅(tong)(tong)、鉛青銅(tong)(tong)、硅青銅(tong)(tong)等。青銅(tong)(tong)通(tong)常(chang)由(you)澆鑄而成,其強度、硬(ying)度及耐腐蝕性都比黃(huang)銅(tong)(tong)好。青銅(tong)(tong)常(chang)用(yong)于(yu)制造蝸(gua)輪(lun)、齒輪(lun)、輪(lun),以(yi)及管道工(gong)程中的閥(fa)件和(he)管件等。
2. 鋁(Aluminum)
鋁(lv)的(de)熔點為527℃,它(ta)具有良好的(de)導熱(re)性(xing)和導電性(xing),強度(du)和硬度(du)較低(di),可塑性(xing)好。鋁(lv)容易氧(yang)化,在空氣中,鋁(lv)的(de)表面能形成一層極薄的(de)氧(yang)化鋁(lv)保護膜,防止繼續(xu)氧(yang)化。鋁(lv)合金薄板(ban)常作(zuo)為壓力(li)管道絕熱(re)工(gong)程的(de)管子、塔、罐、換熱(re)器、閥門、法蘭以及(ji)其(qi)他平壁(bi)設備保護層材料(liao)。
純鋁(lv)的強度(du)和硬度(du)雖(sui)然很低,但(dan)若加入其他元素(su)可以(yi)提高(gao)。鋁(lv)合金分為鑄造鋁(lv)合金和可壓(ya)迫變(bian)形(xing)的鋁(lv)合金兩大(da)類。管(guan)道工程中,常(chang)用L2和L3牌號的鋁(lv)管(guan)輸送(song)硝酸和醋酸等,但(dan)是(shi)鋁(lv)不能抵抗堿性腐蝕(shi)。當溫(wen)度(du)高(gao)于150℃時(shi),鋁(lv)管(guan)不宜用于壓(ya)力(li)管(guan)道。鋁(lv)和鋁(lv)合金管(guan)的標準規范有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(he)金管法蘭(lan)”。
3. 鉛(qian)(Lead)
鉛(qian)(qian)是一(yi)種暗灰色的(de)(de)(de)(de)金(jin)屬,熔點為(wei)(wei)327℃,它(ta)有(you)很好的(de)(de)(de)(de)耐腐(fu)蝕性能,常用(yong)(yong)來制(zhi)作硫(liu)酸設(she)備(bei)和管(guan)(guan)道(dao)襯(chen)里。鉛(qian)(qian)質(zhi)軟,可塑(su)性好,管(guan)(guan)道(dao)工(gong)程中常用(yong)(yong)鉛(qian)(qian)管(guan)(guan)。在(zai)安裝鑄鐵管(guan)(guan)承插口時,常用(yong)(yong)鉛(qian)(qian)作為(wei)(wei)接(jie)口填(tian)塞(sai)材料,以牌號為(wei)(wei)Pb-6的(de)(de)(de)(de)鉛(qian)(qian)較(jiao)適(shi)宜。硬(ying)鉛(qian)(qian)是鉛(qian)(qian)和銻的(de)(de)(de)(de)合金(jin),它(ta)的(de)(de)(de)(de)抗(kang)腐(fu)蝕性略低于純鉛(qian)(qian),但機械(xie)強度較(jiao)高,常用(yong)(yong)于制(zhi)造耐酸設(she)備(bei)。鉛(qian)(qian)蒸氣(qi)有(you)毒(du),故熔化(hua)鉛(qian)(qian)時,要(yao)防止燙(tang)傷和鉛(qian)(qian)中毒(du)。在(zai)化(hua)工(gong)行業中,鉛(qian)(qian)主要(yao)用(yong)(yong)在(zai)處理硫(liu)酸的(de)(de)(de)(de)設(she)備(bei)上。Pb-4用(yong)(yong)于設(she)備(bei)內襯(chen),Pb-6用(yong)(yong)于管(guan)(guan)道(dao)接(jie)頭,硬(ying)鉛(qian)(qian)可制(zhi)造硫(liu)酸工(gong)業用(yong)(yong)的(de)(de)(de)(de)泵、閥(fa)門、管(guan)(guan)道(dao)等。
4. 鋅(Zinc)
鋅呈(cheng)淺灰色,熔點為419℃,它有較好的耐(nai)腐(fu)蝕性和(he)力(li)學性能(neng)。有些鋼管(guan)和(he)管(guan)件為增強耐(nai)腐(fu)蝕性能(neng),常在表面鍍一層鋅,如室內給水工程中常用(yong)的鍍鋅管(guan)。

