管道工程中常(chang)用的有(you)色(se)金(jin)屬(shu)(Non-ferrous Metal)有(you)銅、鋁、鉛和鋅等。
1. 銅(tong)(Copper)
銅(tong)又(you)分純(chun)銅(tong)(俗稱紫銅(tong))、黃銅(tong)和青銅(tong)等。有關銅(tong)管的標準規范包括 ASTM B42、ASTM B43、ASTM B315、ASTM B466、ASTM B467,有關銅(tong)管件的標準規范有ASMEB16.24、ASME B16.22、ASME B16.15、ASME B16.18等。
a. 純銅(Copper)
純(chun)(chun)銅(tong)(tong)呈(cheng)紫紅色,有良好的(de)(de)導(dao)電性(xing)、導(dao)熱(re)性(xing)和耐大氣(qi)腐蝕性(xing),熔點為1083℃。在(zai)(zai)管(guan)道(dao)(dao)(dao)工程中(zhong)常用(yong)(yong)純(chun)(chun)銅(tong)(tong)制成鋼(gang)管(guan)和法蘭(lan)墊片。因純(chun)(chun)銅(tong)(tong)硬度較低,退火(huo)后變得(de)更柔軟,故常用(yong)(yong)來制作高壓(ya)管(guan)道(dao)(dao)(dao)中(zhong) 的(de)(de)法蘭(lan)墊片。純(chun)(chun)銅(tong)(tong)管(guan)的(de)(de)低溫(wen)(wen)性(xing)能(neng)比鋼(gang)材好,故純(chun)(chun)銅(tong)(tong)管(guan)常用(yong)(yong)于空分(fen)設備管(guan)道(dao)(dao)(dao)、冷凍管(guan)道(dao)(dao)(dao)和儀表管(guan)道(dao)(dao)(dao)。純(chun)(chun)銅(tong)(tong)的(de)(de)高溫(wen)(wen)性(xing)能(neng)差,在(zai)(zai)120℃以下,允(yun)許抗(kang)拉(la)(la)強(qiang)度為29.43MPa。溫(wen)(wen)度若再升(sheng)高,其機(ji)械(xie)強(qiang)度則急劇(ju)下降,當溫(wen)(wen)度上(shang)升(sheng)至250℃時,其允(yun)許抗(kang)拉(la)(la)強(qiang)度只相當于常溫(wen)(wen)時的(de)(de)2/3,已不(bu)宜(yi)在(zai)(zai)壓(ya)力下使(shi)用(yong)(yong)。
常(chang)用的純銅(tong)牌號為T2、T3、T4,雜(za)質含量T2最少,T4最多。
b. 黃銅(Brass)
黃(huang)銅(tong)(tong)(tong)是(shi)銅(tong)(tong)(tong)和鋅的(de)(de)合金(jin),其(qi)(qi)機械強(qiang)度高,有(you)較好的(de)(de)耐腐(fu)蝕性和澆鑄性,可(ke)用來(lai)制作管(guan)(guan)(guan)子、管(guan)(guan)(guan)件和閥(fa)門等(deng)。化工上(shang)常用的(de)(de)有(you)H80、H68、H62(“H”是(shi)黃(huang)銅(tong)(tong)(tong)代(dai)號,后邊的(de)(de)數字表示合金(jin)中銅(tong)(tong)(tong)的(de)(de)平均含量)。H80比H68塑(su)性好。進(jin)行強(qiang)度計算時,在(zai)120℃以下(xia),黃(huang)銅(tong)(tong)(tong)允(yun)許抗拉(la)強(qiang)度為29.43MPa。隨著(zhu)溫(wen)度升高,其(qi)(qi)強(qiang)度則急(ji)劇下(xia)降(jiang),當溫(wen)度未超(chao)過(guo)225℃時,黃(huang)銅(tong)(tong)(tong)閥(fa)件可(ke)用在(zai)壓(ya)力不超(chao)過(guo)1.6MPa的(de)(de)管(guan)(guan)(guan)道中。
c. 青銅(Bronze)
青銅(tong)是銅(tong)和錫(xi)的合金,又稱錫(xi)青銅(tong)。由于錫(xi)的價(jia)格較高,故(gu)制(zhi)造青銅(tong)也常(chang)用其他元素代替,因而又有無錫(xi)青銅(tong),如鋁青銅(tong)、鉛青銅(tong)、硅青銅(tong)等。青銅(tong)通常(chang)由澆鑄而成,其強(qiang)度(du)(du)、硬度(du)(du)及(ji)耐腐蝕性(xing)都比(bi)黃銅(tong)好。青銅(tong)常(chang)用于制(zhi)造蝸輪、齒(chi)輪、輪,以及(ji)管道工程中的閥(fa)件(jian)和管件(jian)等。
2. 鋁(Aluminum)
鋁(lv)(lv)的(de)熔點為527℃,它具(ju)有良(liang)好的(de)導熱性(xing)和導電性(xing),強度和硬度較(jiao)低,可塑性(xing)好。鋁(lv)(lv)容易氧(yang)化,在空氣中,鋁(lv)(lv)的(de)表(biao)面能形成一層(ceng)(ceng)極薄的(de)氧(yang)化鋁(lv)(lv)保護膜,防止繼續(xu)氧(yang)化。鋁(lv)(lv)合(he)金(jin)薄板常(chang)作為壓力管道絕(jue)熱工程(cheng)的(de)管子、塔、罐(guan)、換熱器、閥門、法蘭以及其他平壁設備保護層(ceng)(ceng)材(cai)料。
純鋁的(de)強(qiang)度(du)和硬(ying)度(du)雖(sui)然很低,但(dan)若加入(ru)其(qi)他元素(su)可以提高。鋁合金(jin)分為鑄造鋁合金(jin)和可壓(ya)迫變形的(de)鋁合金(jin)兩(liang)大類。管(guan)道工程(cheng)中(zhong),常用(yong)L2和L3牌號的(de)鋁管(guan)輸送硝酸(suan)和醋酸(suan)等(deng),但(dan)是鋁不能(neng)抵抗(kang)堿性(xing)腐蝕。當(dang)溫度(du)高于(yu)150℃時,鋁管(guan)不宜用(yong)于(yu)壓(ya)力(li)管(guan)道。鋁和鋁合金(jin)管(guan)的(de)標(biao)準(zhun)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(de)“附錄L-鋁合金管法蘭”。
3. 鉛(Lead)
鉛(qian)(qian)是一種暗(an)灰色的金(jin)屬,熔點為(wei)327℃,它有很好的耐腐蝕性能,常(chang)用(yong)來制(zhi)作硫(liu)酸(suan)設(she)備和(he)管(guan)(guan)(guan)(guan)道襯(chen)里。鉛(qian)(qian)質(zhi)軟,可塑性好,管(guan)(guan)(guan)(guan)道工(gong)程中(zhong)常(chang)用(yong)鉛(qian)(qian)管(guan)(guan)(guan)(guan)。在(zai)(zai)安裝(zhuang)鑄鐵管(guan)(guan)(guan)(guan)承插口時,常(chang)用(yong)鉛(qian)(qian)作為(wei)接口填(tian)塞材料,以(yi)牌號為(wei)Pb-6的鉛(qian)(qian)較(jiao)適宜(yi)。硬鉛(qian)(qian)是鉛(qian)(qian)和(he)銻的合金(jin),它的抗(kang)腐蝕性略(lve)低(di)于(yu)純鉛(qian)(qian),但機械強度較(jiao)高,常(chang)用(yong)于(yu)制(zhi)造耐酸(suan)設(she)備。鉛(qian)(qian)蒸氣有毒(du),故熔化(hua)鉛(qian)(qian)時,要防止燙傷和(he)鉛(qian)(qian)中(zhong)毒(du)。在(zai)(zai)化(hua)工(gong)行業中(zhong),鉛(qian)(qian)主要用(yong)在(zai)(zai)處理硫(liu)酸(suan)的設(she)備上。Pb-4用(yong)于(yu)設(she)備內襯(chen),Pb-6用(yong)于(yu)管(guan)(guan)(guan)(guan)道接頭,硬鉛(qian)(qian)可制(zhi)造硫(liu)酸(suan)工(gong)業用(yong)的泵、閥(fa)門、管(guan)(guan)(guan)(guan)道等。
4. 鋅(Zinc)
鋅(xin)(xin)(xin)呈淺灰色,熔點為(wei)419℃,它有較好的耐腐蝕性和(he)力學性能。有些鋼(gang)管(guan)和(he)管(guan)件為(wei)增強耐腐蝕性能,常在表面鍍(du)一層鋅(xin)(xin)(xin),如(ru)室內給水工程中常用的鍍(du)鋅(xin)(xin)(xin)管(guan)。

