表面熔(rong)覆(fu)(fu)(fu)技(ji)術(shu)可以以較低(di)的(de)(de)成(cheng)本(ben)改善材(cai)料的(de)(de)表面性能，延長材(cai)料的(de)(de)使用(yong)壽命(ming)。與其它熔(rong)覆(fu)(fu)(fu)技(ji)術(shu)相比，氬弧(hu)熔(rong)覆(fu)(fu)(fu)技(ji)術(shu)具有(you)投(tou)資和運行費用(yong)低(di)、操作(zuo)方便等優(you)點，而且(qie)在(zai)氬氣的(de)(de)保護(hu)下熔(rong)池中(zhong)合金元素的(de)(de)燒(shao)損(sun)和氧化損(sun)失(shi)也較少，但其熔(rong)覆(fu)(fu)(fu)效率(lv)低(di)，熔(rong)覆(fu)(fu)(fu)層產生裂(lie)紋或剝(bo)離的(de)(de)傾(qing)向(xiang)較大(da)，這大(da)大(da)限制(zhi)了該(gai)技(ji)術(shu)的(de)(de)發(fa)展(zhan)。科研工(gong)作(zuo)者提出以固體(ti)廢棄物粉(fen)煤灰為活性劑，采用(yong)活性氬弧(hu)熔(rong)覆(fu)(fu)(fu)技(ji)術(shu)在(zai)Q235鋼表面制(zhi)備了B4C增強(qiang)鐵基活性氬弧(hu)熔(rong)覆(fu)(fu)(fu)層，取得了良好效果。

　　粉(fen)煤(mei)(mei)灰(hui)是從煤(mei)(mei)燃燒后的(de)(de)煙(yan)氣(qi)中收(shou)捕的(de)(de)細灰(hui)，粉(fen)煤(mei)(mei)灰(hui)的(de)(de)化學成分主(zhu)要(yao)為SiO2、Al2O3和堿(jian)性(xing)金屬氧(yang)化物，可作為焊接(jie)活(huo)性(xing)劑使(shi)用(yong)。活(huo)性(xing)氬(ya)弧熔(rong)(rong)覆技術(shu)在等熱(re)量輸入條件下可使(shi)焊縫熔(rong)(rong)深大幅增加，使(shi)熔(rong)(rong)覆層與母(mu)材金屬更(geng)好地結合在一起。該(gai)技術(shu)在提高熔(rong)(rong)覆效率(lv)，降低生產成本的(de)(de)同時，也可改善(shan)熔(rong)(rong)覆層的(de)(de)性(xing)能(neng)。

　　他們所(suo)用的(de)熔覆(fu)(fu)層(ceng)材料為(wei)6%B4C、5%硼砂和還原鐵(tie)粉(fen)組(zu)成的(de)混合粉(fen)，在(zai)60MPa壓力下壓制成預置熔覆(fu)(fu)塊(kuai)(kuai)，將熔覆(fu)(fu)塊(kuai)(kuai)置于Q235鋼(gang)表面(mian)進行單道氬弧熔覆(fu)(fu)。熔覆(fu)(fu)工藝(yi)參數為(wei)：熔覆(fu)(fu)電(dian)流145A，熔覆(fu)(fu)速度120mm/min，氬氣(qi)流量7L/min，弧長4mm，鎢極直徑2mm。作為(wei)活性(xing)(xing)劑的(de)粉(fen)煤(mei)灰，其成分為(wei)：SiO2：59.82%，Al2O3：17.32%，Fe2O3：8.23%，CaO：3.64%，K2O：2.75%，MnO：2.61%，Na2O：1.37%，TiO2：0.79%，P2O5：0.26%，MnO：0.11%其它(ta)3.1%。試驗前在(zai)800°C下保溫2小(xiao)時進行熱活化；將其均勻(yun)地涂覆(fu)(fu)在(zai)預置熔覆(fu)(fu)塊(kuai)(kuai)表面(mian)，烘干，然后進行活性(xing)(xing)氬弧熔覆(fu)(fu)。

　　對(dui)所獲活性氬(ya)(ya)弧熔覆層(ceng)(ceng)的相分析表明，其(qi)中不僅存在Fe3C，Fe2B，Fe3B，還存在Fe3.5B和(he)Fe23(C,B)等新相，但卻沒有(you)B4C。這說(shuo)明涂覆粉(fen)煤灰活性劑后(hou)，提高了(le)焊(han)接熱輸(shu)入，使B4C全部(bu)分解，從(cong)而使得有(you)更多的硼與鐵發生(sheng)反應(ying)，并且部(bu)分碳(tan)元素溶(rong)于母(mu)材中形(xing)成了(le)含碳(tan)的固溶(rong)體和(he)碳(tan)化(hua)(hua)物，這些新生(sheng)成的硼化(hua)(hua)物，碳(tan)化(hua)(hua)物及(ji)固溶(rong)體對(dui)提高熔覆層(ceng)(ceng)的硬度及(ji)耐磨(mo)性具(ju)有(you)一定作用。顯微組織檢測表明，活性氬(ya)(ya)弧熔覆層(ceng)(ceng)的晶粒(li)較普(pu)通氬(ya)(ya)弧熔覆層(ceng)(ceng)的更細(xi)小致密，排(pai)布得較為(wei)規則(ze)，這說(shuo)明涂覆粉(fen)煤灰會促進一些細(xi)小第二(er)相的生(sheng)成，并增加了(le)形(xing)核質點的數量。

　　顯(xian)微(wei)硬(ying)度測試(shi)表(biao)明，普(pu)(pu)通(tong)(tong)(tong)氬(ya)(ya)(ya)(ya)弧(hu)熔(rong)(rong)(rong)(rong)覆(fu)(fu)(fu)層(ceng)(ceng)的(de)(de)(de)(de)(de)(de)顯(xian)微(wei)硬(ying)度約為(wei)(wei)300HV，活(huo)性(xing)(xing)氬(ya)(ya)(ya)(ya)弧(hu)熔(rong)(rong)(rong)(rong)覆(fu)(fu)(fu)層(ceng)(ceng)的(de)(de)(de)(de)(de)(de)顯(xian)微(wei)硬(ying)度約為(wei)(wei)360HV，而母(mu)材(cai)的(de)(de)(de)(de)(de)(de)顯(xian)微(wei)硬(ying)度約為(wei)(wei)130HV。磨損試(shi)驗表(biao)明，母(mu)材(cai)的(de)(de)(de)(de)(de)(de)磨損量最(zui)大，普(pu)(pu)通(tong)(tong)(tong)氬(ya)(ya)(ya)(ya)弧(hu)熔(rong)(rong)(rong)(rong)覆(fu)(fu)(fu)層(ceng)(ceng)的(de)(de)(de)(de)(de)(de)次(ci)之，活(huo)性(xing)(xing)氬(ya)(ya)(ya)(ya)弧(hu)熔(rong)(rong)(rong)(rong)覆(fu)(fu)(fu)層(ceng)(ceng)的(de)(de)(de)(de)(de)(de)最(zui)小。普(pu)(pu)通(tong)(tong)(tong)氬(ya)(ya)(ya)(ya)弧(hu)熔(rong)(rong)(rong)(rong)覆(fu)(fu)(fu)層(ceng)(ceng)的(de)(de)(de)(de)(de)(de)耐(nai)(nai)(nai)磨性(xing)(xing)為(wei)(wei)母(mu)材(cai)的(de)(de)(de)(de)(de)(de)1.98倍，活(huo)性(xing)(xing)氬(ya)(ya)(ya)(ya)弧(hu)熔(rong)(rong)(rong)(rong)覆(fu)(fu)(fu)層(ceng)(ceng)的(de)(de)(de)(de)(de)(de)則提高(gao)至(zhi)2.3倍；活(huo)性(xing)(xing)氬(ya)(ya)(ya)(ya)弧(hu)熔(rong)(rong)(rong)(rong)覆(fu)(fu)(fu)層(ceng)(ceng)的(de)(de)(de)(de)(de)(de)耐(nai)(nai)(nai)磨性(xing)(xing)為(wei)(wei)普(pu)(pu)通(tong)(tong)(tong)氬(ya)(ya)(ya)(ya)弧(hu)熔(rong)(rong)(rong)(rong)覆(fu)(fu)(fu)層(ceng)(ceng)的(de)(de)(de)(de)(de)(de)1.16倍。另外，活(huo)性(xing)(xing)氬(ya)(ya)(ya)(ya)弧(hu)熔(rong)(rong)(rong)(rong)覆(fu)(fu)(fu)層(ceng)(ceng)和(he)普(pu)(pu)通(tong)(tong)(tong)氬(ya)(ya)(ya)(ya)弧(hu)熔(rong)(rong)(rong)(rong)覆(fu)(fu)(fu)層(ceng)(ceng)的(de)(de)(de)(de)(de)(de)相對耐(nai)(nai)(nai)沖(chong)蝕性(xing)(xing)能分別為(wei)(wei)母(mu)材(cai)的(de)(de)(de)(de)(de)(de)4.70倍和(he)2.52倍；活(huo)性(xing)(xing)氬(ya)(ya)(ya)(ya)弧(hu)熔(rong)(rong)(rong)(rong)覆(fu)(fu)(fu)層(ceng)(ceng)的(de)(de)(de)(de)(de)(de)耐(nai)(nai)(nai)沖(chong)蝕性(xing)(xing)能為(wei)(wei)普(pu)(pu)通(tong)(tong)(tong)氬(ya)(ya)(ya)(ya)弧(hu)熔(rong)(rong)(rong)(rong)覆(fu)(fu)(fu)層(ceng)(ceng)的(de)(de)(de)(de)(de)(de)1.86倍。

　　上(shang)述試驗證明(ming)，以粉煤(mei)灰為活性(xing)劑，采(cai)用活性(xing)氬(ya)弧熔覆(fu)技術在鋼材表面(mian)制備活性(xing)氬(ya)弧熔覆(fu)層可以明(ming)顯提高鋼材的耐磨粒磨損性(xing)能和(he)耐沖蝕磨損性(xing)能。