鉛的作用和錫鉛青銅

鉛不(bu)固溶(rong)于青(qing)銅(tong)(tong),以(yi)純(chun)組元狀態存在(zai),呈黑(hei)色夾(jia)雜(za)物(wu)分布(bu)在(zai)枝晶(jing)之間,可(ke)(ke)改(gai)善切削(xue)和(he)耐(nai)(nai)磨性(xing)(xing)。含鉛低時(如1~2%)主要(yao)改(gai)善切削(xue)性(xing)(xing),含鉛高時(4~5%)用(yong)(yong)作軸承材料,降低摩擦系數(shu)。所以(yi)錫鉛青(qing)銅(tong)(tong)用(yong)(yong)以(yi)制造耐(nai)(nai)蝕(shi)、耐(nai)(nai)磨、易切削(xue)零(ling)件或軸套、軸承內襯等零(ling)件。微(wei)量Zr、B、Ti可(ke)(ke)細化晶(jing)粒(li),改(gai)善錫青(qing)銅(tong)(tong)的(de)機(ji)械性(xing)(xing)能和(he)冷(leng)熱加(jia)工性(xing)(xing)能。As、Sb、Bi降低錫青(qing)銅(tong)(tong)的(de)塑性(xing)(xing),對冷(leng)熱加(jia)工性(xing)(xing)能有害。