摘要：<span style="font-family:宋體;">不鏽鋼中鉬含量的影響</span> <p> <span style="font-family:宋體;">一般來(lái)說(shuō)</span><span>,</span><span style="font-family:宋體;">簡(jiǎn)單的鉻鎳</span><span>(</span><span style="font-family:宋體;">及鉻錳氮</span><span>)</span><span style="font-family:宋體;">奧氏體不鏽鋼僅用於要求不鏽性和耐氧化性介質(zhì)</span><span>(</span><span style="font-family:宋體;">比如硝酸等</span><span>)</span><span style="font-family:宋體;">的使用條件下</span><span>,</span><span style="font-family:宋體;">鉬作為奧氏體不鏽鋼中的重要合金元素加入到鋼中使其使用範(fàn)圍進(jìn)一步擴(kuò)大</span><span>,</span><span style="font-family:宋體;">鉬的作用主要是提高鋼在還原性介質(zhì)</span><span>(</span><span style="font-family:宋體;">比</span><span>H2SO4,H3PO4,</span><span style="font-family:宋體;">以及一些有機(jī)酸和尿素環(huán)境</span><span>)</span><span style="font-family:宋體;">的耐蝕性</span><span>,</span><span style="font-family:宋體;">並提高鋼的耐點(diǎn)腐蝕及縫隙腐蝕等性能</span><span>. <br /> 1</span><span style="font-family:宋體;">鉬對(duì)組織的影響</span><span> <br /> </span><span style="font-family:宋體;">鉬和鉻都是形成和穩(wěn)定鐵素體並擴(kuò)大鐵素體相區(qū)的元素</span><span>,</span><span style="font-family:宋體;">鉬形成鐵素體的能力與鉻相當(dāng)</span><span>.</span><span style="font-family:宋體;">鉬還促進(jìn)奧氏體不鏽鋼中金屬間相</span><span>,</span><span style="font-family:宋體;">比如</span><span>σ</span><span style="font-family:宋體;">相</span><span>,,κ</span><span style="font-family:宋體;">相</span><span>,</span><span style="font-family:宋體;">和</span><span>Laves</span><span style="font-family:宋體;">相等的沉澱</span><span>,</span><span style="font-family:宋體;">對(duì)鋼的耐蝕性和力學(xué)性能都會(huì)產(chǎn)生不利影響</span><span>,</span><span style="font-family:宋體;">告彆是導(dǎo)致塑性</span><span>,</span><span style="font-family:宋體;">韌性下降</span><span>,</span><span style="font-family:宋體;">為使奧氏體不鏽鋼保持單一的奧氏體組織</span><span>,</span><span style="font-family:宋體;">隨著鋼中鉬含量的增加</span><span>,</span><span style="font-family:宋體;">奧氏體形成元素</span><span>(</span><span style="font-family:宋體;">鎳</span><span>,</span><span style="font-family:宋體;">氮及錳等</span><span>)</span><span style="font-family:宋體;">的含量也要相應(yīng)提高</span><span>,</span><span style="font-family:宋體;">以保持鋼中鐵素體與奧氏體形成元素之間的平衡</span><span>.<br /> 2</span><span style="font-family:宋體;">鉬對(duì)性能的影響</span><span> <br /> </span><span style="font-family:宋體;">鉬對(duì)奧氏體不鏽鋼的氧化作用不顯著</span><span>,</span><span style="font-family:宋體;">因此當(dāng)鉻鎳奧氏體不鏽鋼保持單一的奧氏體組織且無(wú)金屬間析出時(shí)</span><span>,</span><span style="font-family:宋體;">鉬的加入對(duì)其室溫力學(xué)性能影響不大</span><span>,</span><span style="font-family:宋體;">但是</span><span>,</span><span style="font-family:宋體;">隨著鉬含量的增加</span><span>,</span><span style="font-family:宋體;">鋼的高溫強(qiáng)度提高</span><span>,</span><span style="font-family:宋體;">比如持久</span><span>,</span><span style="font-family:宋體;">蠕變等性能均獲較大改善</span><span>,</span><span style="font-family:宋體;">因此含鉬不鏽鋼也常在高溫下應(yīng)用</span><span>,</span><span style="font-family:宋體;">然而</span><span>,</span><span style="font-family:宋體;">鉬的加入使鋼的高溫變形抗力增大</span><span>,</span><span style="font-family:宋體;">加之鋼中常常存在少量</span><span>δ</span><span style="font-family:宋體;">鐵素體因而含鉬不鏽鋼的熱衷加工性比不含鉬鋼為差</span><span>,</span><span style="font-family:宋體;">而且鉬含量越高</span><span>,</span><span style="font-family:宋體;">熱加工性能越壞</span><span>,</span><span style="font-family:宋體;">另外</span><span>,</span><span style="font-family:宋體;">含鉬奧氏體不鏽鋼中容易一百萬(wàn)</span><span>κ(σ)</span><span style="font-family:宋體;">相沉澱</span><span>,</span><span style="font-family:宋體;">這將顯著惡化鋼的塑性和韌性</span><span>,</span><span style="font-family:宋體;">因此在含鉬奧氏體不鏽鋼的生產(chǎn)</span><span>,</span><span style="font-family:宋體;">設(shè)備製造和應(yīng)用過(guò)程中</span><span>,</span><span style="font-family:宋體;">要注意防止鋼中金屬間相的形成</span><span>.<br /> </span><span style="font-family:宋體;">鉬在奧氏體不鏽鋼中的主要作用是提高鋼的耐還原性介質(zhì)的腐蝕性能和耐點(diǎn)腐蝕</span><span>,</span><span style="font-family:宋體;">耐縫隙腐蝕等的性能</span><span>.</span><span style="font-family:宋體;">分彆為鉬對(duì)鉻鎳奧氏體不鏽鋼在硝酸</span><span>,</span><span style="font-family:宋體;">硫酸</span><span>,</span><span style="font-family:宋體;">醋酸</span><span>,</span><span style="font-family:宋體;">磷酸和尿素等介質(zhì)中耐蝕性的影響</span><span>,</span><span style="font-family:宋體;">可以看出</span><span>,</span><span style="font-family:宋體;">除在氧化性介質(zhì)</span><span>HNO3</span><span style="font-family:宋體;">中處</span><span>,</span><span style="font-family:宋體;">鉬的作用都是有益的</span><span>,</span><span style="font-family:宋體;">因此含鉬的奧氏體不鏽鋼一般不用天耐硝酸的腐蝕</span><span>,</span><span style="font-family:宋體;">除非硝酸中含</span><span>F-,Cl-</span><span style="font-family:宋體;">等離子</span><span>,<br /> </span><span style="font-family:宋體;">雖然鉬作用為合金元素對(duì)奧氏體不鏽鋼耐還原性介質(zhì)</span><span>,</span><span style="font-family:宋體;">麵點(diǎn)腐蝕及縫隙腐蝕的原因尚不完全清楚</span><span>,</span><span style="font-family:宋體;">但大量實(shí)驗(yàn)已指出</span><span>,</span><span style="font-family:宋體;">鉬的耐蝕作用僅相當(dāng)鋼中含有較高量的鉻時(shí)才有效</span><span>,</span><span style="font-family:宋體;">鉬主要是強(qiáng)化鋼中鉻的耐蝕作用</span><span>,</span><span style="font-family:宋體;">與此同時(shí)</span><span>,</span><span style="font-family:宋體;">鉬形成酸鹽後的緩蝕作用也已為實(shí)驗(yàn)所證實(shí)</span><span>.<br /> </span><span style="font-family:宋體;">在耐高濃氯化物溶液的應(yīng)力腐蝕方麵</span><span>,</span><span style="font-family:宋體;">雖然鉬作為合金元素對(duì)奧氏體不鏽鋼耐還原性介質(zhì)</span><span>,</span><span style="font-family:宋體;">耐點(diǎn)腐蝕及縫隙腐蝕的原因尚不完全清楚</span><span>,</span><span style="font-family:宋體;">但大量實(shí)驗(yàn)已指出</span><span>,</span><span style="font-family:宋體;">鉬的作用僅當(dāng)鋼中含有較高量的鉻時(shí)才有效</span><span>,</span><span style="font-family:宋體;">鉬主要是強(qiáng)化鋼中鉻的耐蝕作用</span><span>,</span><span style="font-family:宋體;">與此同時(shí)</span><span>,</span><span style="font-family:宋體;">鉬形成鉬酸鹽後的緩衝作用也已為實(shí)驗(yàn)所證實(shí)</span><span>.<br /> </span><span style="font-family:宋體;">在耐高濃氯化物沉淪的應(yīng)力腐蝕方麵</span><span>,</span><span style="font-family:宋體;">雖然一此實(shí)驗(yàn)指同</span><span>.32_1.html</span><span style="font-family:宋體;">以下的鉬對(duì)奧氏體不鏽鋼的耐應(yīng)力腐蝕性能有害</span><span>,,</span><span style="font-family:宋體;">但是由於常見(jiàn)鉻鎳奧氏體不鏽鋼多在含有微量氯化物及飽和氧的水介質(zhì)中使用</span><span>,</span><span style="font-family:宋體;">其應(yīng)力腐蝕又以點(diǎn)腐蝕為起源</span><span>,</span><span style="font-family:宋體;">因此含鉬的鉻鎳鉬奧氏體不鏽鋼由於耐點(diǎn)腐蝕性能較高</span><span>,</span><span style="font-family:宋體;">所以在實(shí)際應(yīng)用中常常比不含鉬鋼具有更好的耐氯化物應(yīng)力腐蝕性能</span><span>.</span> </p> <p> <span></span> </p>