管道工程中常用的有色金(jin)屬(Non-ferrous Metal)有銅(tong)、鋁、鉛(qian)和(he)鋅等(deng)。
1. 銅(Copper)
銅又(you)分純銅(俗稱紫銅)、黃銅和青(qing)銅等。有(you)關銅管(guan)的(de)標準(zhun)規范(fan)包括 ASTM B42、ASTM B43、ASTM B315、ASTM B466、ASTM B467,有(you)關銅管(guan)件的(de)標準(zhun)規范(fan)有(you)ASMEB16.24、ASME B16.22、ASME B16.15、ASME B16.18等。
a. 純(chun)銅(Copper)
純(chun)銅(tong)(tong)呈紫紅色,有良(liang)好的(de)(de)導電性(xing)、導熱性(xing)和耐(nai)大氣腐蝕性(xing),熔點(dian)為1083℃。在管(guan)道(dao)工程中常(chang)用(yong)純(chun)銅(tong)(tong)制成鋼(gang)(gang)管(guan)和法(fa)蘭(lan)墊片。因(yin)純(chun)銅(tong)(tong)硬度較低(di),退火后變得更柔軟,故常(chang)用(yong)來(lai)制作高壓(ya)管(guan)道(dao)中 的(de)(de)法(fa)蘭(lan)墊片。純(chun)銅(tong)(tong)管(guan)的(de)(de)低(di)溫(wen)性(xing)能比(bi)鋼(gang)(gang)材好,故純(chun)銅(tong)(tong)管(guan)常(chang)用(yong)于(yu)空分(fen)設備管(guan)道(dao)、冷(leng)凍管(guan)道(dao)和儀表管(guan)道(dao)。純(chun)銅(tong)(tong)的(de)(de)高溫(wen)性(xing)能差,在120℃以下,允許抗拉(la)強度為29.43MPa。溫(wen)度若再升高,其(qi)機械強度則急劇下降(jiang),當溫(wen)度上升至250℃時,其(qi)允許抗拉(la)強度只相當于(yu)常(chang)溫(wen)時的(de)(de)2/3,已不(bu)宜在壓(ya)力下使(shi)用(yong)。
常(chang)用的純銅(tong)牌號(hao)為T2、T3、T4,雜質含量T2最少,T4最多。
b. 黃銅(Brass)
黃銅(tong)(tong)是(shi)銅(tong)(tong)和(he)鋅(xin)的(de)合金,其機械強度高,有較好(hao)的(de)耐腐蝕性和(he)澆鑄性,可用來制作管子(zi)、管件(jian)和(he)閥門(men)等。化工上常用的(de)有H80、H68、H62(“H”是(shi)黃銅(tong)(tong)代號(hao),后邊的(de)數字表示合金中(zhong)(zhong)銅(tong)(tong)的(de)平均含量)。H80比H68塑性好(hao)。進行(xing)強度計算時,在120℃以下(xia),黃銅(tong)(tong)允許(xu)抗拉強度為29.43MPa。隨著溫度升高,其強度則急劇下(xia)降,當溫度未超過(guo)225℃時,黃銅(tong)(tong)閥件(jian)可用在壓力不超過(guo)1.6MPa的(de)管道中(zhong)(zhong)。
c. 青銅(Bronze)
青銅(tong)(tong)(tong)是銅(tong)(tong)(tong)和錫的(de)(de)合金(jin),又稱錫青銅(tong)(tong)(tong)。由于(yu)(yu)錫的(de)(de)價格較高,故制(zhi)造青銅(tong)(tong)(tong)也常(chang)(chang)用其他元素代替,因而又有無錫青銅(tong)(tong)(tong),如(ru)鋁青銅(tong)(tong)(tong)、鉛青銅(tong)(tong)(tong)、硅青銅(tong)(tong)(tong)等。青銅(tong)(tong)(tong)通常(chang)(chang)由澆鑄(zhu)而成,其強度、硬度及耐腐蝕(shi)性都比黃銅(tong)(tong)(tong)好。青銅(tong)(tong)(tong)常(chang)(chang)用于(yu)(yu)制(zhi)造蝸輪(lun)、齒輪(lun)、輪(lun),以(yi)及管道工(gong)程中的(de)(de)閥件和管件等。
2. 鋁(Aluminum)
鋁(lv)的(de)熔點為(wei)527℃,它(ta)具有良好的(de)導熱性(xing)(xing)和導電性(xing)(xing),強度(du)和硬度(du)較低,可(ke)塑性(xing)(xing)好。鋁(lv)容易氧化,在空(kong)氣中,鋁(lv)的(de)表面(mian)能形成一層極(ji)薄的(de)氧化鋁(lv)保護(hu)膜,防止繼(ji)續氧化。鋁(lv)合金(jin)薄板常作(zuo)為(wei)壓力(li)管(guan)道(dao)絕熱工程的(de)管(guan)子、塔(ta)、罐、換熱器(qi)、閥門、法蘭以及其他平壁(bi)設(she)備保護(hu)層材料。
純鋁的(de)強(qiang)度(du)和硬度(du)雖然很(hen)低,但若加入其他元(yuan)素可(ke)以提高。鋁合(he)金(jin)分為(wei)鑄(zhu)造鋁合(he)金(jin)和可(ke)壓(ya)迫變形(xing)的(de)鋁合(he)金(jin)兩大類(lei)。管道工程中,常用L2和L3牌號(hao)的(de)鋁管輸送硝酸(suan)和醋酸(suan)等,但是鋁不能(neng)抵(di)抗(kang)堿性腐蝕(shi)。當溫(wen)度(du)高于(yu)150℃時,鋁管不宜用于(yu)壓(ya)力管道。鋁和鋁合(he)金(jin)管的(de)標(biao)準規范有(you)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(guan)法蘭”。
3. 鉛(Lead)
鉛(qian)(qian)(qian)(qian)是(shi)一種暗灰(hui)色的(de)金(jin)屬,熔點(dian)為(wei)327℃,它有很好的(de)耐(nai)腐蝕性(xing)(xing)能,常(chang)用(yong)(yong)來制作(zuo)硫酸(suan)(suan)設備(bei)和(he)管道襯里。鉛(qian)(qian)(qian)(qian)質軟(ruan),可塑性(xing)(xing)好,管道工(gong)程中(zhong)常(chang)用(yong)(yong)鉛(qian)(qian)(qian)(qian)管。在安裝鑄鐵管承(cheng)插口時(shi),常(chang)用(yong)(yong)鉛(qian)(qian)(qian)(qian)作(zuo)為(wei)接口填(tian)塞材料(liao),以牌(pai)號為(wei)Pb-6的(de)鉛(qian)(qian)(qian)(qian)較(jiao)適宜。硬鉛(qian)(qian)(qian)(qian)是(shi)鉛(qian)(qian)(qian)(qian)和(he)銻(ti)的(de)合(he)金(jin),它的(de)抗腐蝕性(xing)(xing)略低于(yu)純鉛(qian)(qian)(qian)(qian),但(dan)機械強度較(jiao)高,常(chang)用(yong)(yong)于(yu)制造(zao)耐(nai)酸(suan)(suan)設備(bei)。鉛(qian)(qian)(qian)(qian)蒸氣有毒,故熔化鉛(qian)(qian)(qian)(qian)時(shi),要(yao)(yao)防止燙傷和(he)鉛(qian)(qian)(qian)(qian)中(zhong)毒。在化工(gong)行業(ye)中(zhong),鉛(qian)(qian)(qian)(qian)主(zhu)要(yao)(yao)用(yong)(yong)在處理硫酸(suan)(suan)的(de)設備(bei)上。Pb-4用(yong)(yong)于(yu)設備(bei)內襯,Pb-6用(yong)(yong)于(yu)管道接頭,硬鉛(qian)(qian)(qian)(qian)可制造(zao)硫酸(suan)(suan)工(gong)業(ye)用(yong)(yong)的(de)泵、閥門、管道等。
4. 鋅(xin)(Zinc)
鋅呈淺灰(hui)色,熔點為419℃,它有較好的(de)耐腐蝕性(xing)和力學性(xing)能(neng)。有些鋼管和管件為增(zeng)強耐腐蝕性(xing)能(neng),常在(zai)表(biao)面鍍一層(ceng)鋅,如(ru)室(shi)內給水工程中常用的(de)鍍鋅管。

