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西安雙相不鏽鋼管的焊接要求

日期:2024-03-29 14:12
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摘要:<span style="font-family:宋體;font-size:small;"> </span> <p style="margin:0cm 0cm 0pt;"> <span style="font-family:宋體;mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;"><span style="font-size:small;">西安雙相不鏽鋼管的焊接要求</span></span> </p> <span style="font-family:宋體;font-size:small;"> </span> <p style="margin:0cm 0cm 0pt;"> <span style="font-size:small;"><span style="font-family:宋體;mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">在石油化工裝置中一種新型鋼材</span><span style="font-family:'Times New Roman';"><span lang="EN-US">-</span></span><span style="font-family:宋體;mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">雙相不鏽鋼的應用越來越多。因為雙相不鏽鋼的屈服強度是普通不鏽鋼的</span><span style="font-family:'Times New Roman';"><span lang="EN-US">2</span></span><span style="font-family:宋體;mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">倍,抗腐蝕性能(特彆是在腐蝕性介質中)明顯優於普通不鏽鋼,在石油化工裝置施工中多用在很重要的位置。因此,一般雙相不鏽鋼的焊縫要求</span><span style="font-family:'Times New Roman';"><span lang="EN-US">100%RT</span></span><span style="font-family:宋體;mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">檢驗,對其焊接接頭的綜合性能的要求也高於一般奧氏體不鏽鋼。所以,必須選派焊接經驗豐富的奧氏體不鏽鋼焊工,經培訓和考試合格後,才能持證上崗進行焊接作業。</span></span><span lang="EN-US"><br /> <span style="font-family:'Times New Roman';font-size:small;"> 1&nbsp; &nbsp; </span></span><span style="font-family:宋體;mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;"><span style="font-size:small;">焊接性分析</span></span><span lang="EN-US"><br /> <span style="font-family:'Times New Roman';font-size:small;"> </span></span><span style="font-size:small;"><span style="font-family:宋體;mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">雙相不鏽鋼焊接時,焊接熱影響區(</span><span style="font-family:'Times New Roman';"><span lang="EN-US">HAZ</span></span><span style="font-family:宋體;mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">)</span></span><span style="font-family:'Times New Roman';font-size:small;"> </span><span style="font-size:small;"><span style="font-family:宋體;mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">存在高溫區和低溫區,低溫區基本處於</span><span style="font-family:'Times New Roman';"><span lang="EN-US">δ+γ</span></span><span style="font-family:宋體;mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">(鐵素體</span><span style="font-family:'Times New Roman';"><span lang="EN-US">+</span></span><span style="font-family:宋體;mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">奧氏體)平衡組織,而高溫區幾乎為單相</span><span style="font-family:'Times New Roman';"><span lang="EN-US">δ</span></span><span style="font-family:宋體;mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">組織,因為焊縫根部和表麵</span><span style="font-family:'Times New Roman';"><span lang="EN-US">N</span></span><span style="font-family:宋體;mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">的擴散,導致靠近焊縫表麵的部位,由於</span><span style="font-family:'Times New Roman';"><span lang="EN-US">N</span></span><span style="font-family:宋體;mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">的損失,鐵素體增加,從而促進氮化物的產生,使焊接接頭性能惡化,焊接采用高線能量時,可以得到較多的</span><span style="font-family:'Times New Roman';"><span lang="EN-US">γ</span></span><span style="font-family:宋體;mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">相,鐵素體含量低會促進</span><span style="font-family:'Times New Roman';"><span lang="EN-US">δ</span></span><span style="font-family:宋體;mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">相產生,所以容易產生</span><span style="font-family:'Times New Roman';"><span lang="EN-US">δ</span></span><span style="font-family:宋體;mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">相和粗晶組織;線能量較低時,得不到足夠的</span><span style="font-family:'Times New Roman';"><span lang="EN-US">γ</span></span><span style="font-family:宋體;mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">相。如果焊接金屬中</span><span style="font-family:'Times New Roman';"><span lang="EN-US">δ</span></span><span style="font-family:宋體;mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">相過多,</span><span style="font-family:'Times New Roman';"><span lang="EN-US">N</span></span><span style="font-family:宋體;mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">很容易與</span><span style="font-family:'Times New Roman';"><span lang="EN-US">cγ</span></span><span style="font-family:宋體;mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">形成化合物,而且析出二次</span><span style="font-family:'Times New Roman';"><span lang="EN-US">γ</span></span><span style="font-family:宋體;mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">變為針狀和羽毛狀,具有魏氏體組織特性,導致焊接接頭力學性能和耐腐蝕性下降。雙相鋼一般不會產生</span><span style="font-family:'Times New Roman';"><span lang="EN-US">δ</span></span><span style="font-family:宋體;mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">相,但如果焊接線能量較高,導致使焊接頭塑性大幅度下降。</span></span><span lang="EN-US"><br /> <span style="font-family:'Times New Roman';font-size:small;"> 2&nbsp; &nbsp; </span></span><span style="font-family:宋體;mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;"><span style="font-size:small;">焊接工藝</span></span><span lang="EN-US"><br /> <span style="font-family:'Times New Roman';font-size:small;"> 2.1&nbsp; &nbsp; </span></span><span style="font-size:small;"><span style="font-family:宋體;mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">工藝參數及電特性(見表</span><span style="font-family:'Times New Roman';"><span lang="EN-US">2</span></span><span style="font-family:宋體;mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">)</span></span><span lang="EN-US"><br /> <span style="font-family:'Times New Roman';font-size:small;"> 2.2&nbsp; &nbsp; </span></span><span style="font-family:宋體;mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;"><span style="font-size:small;">焊接方法</span></span><span lang="EN-US"><br /> <span style="font-family:'Times New Roman';font-size:small;"> </span></span><span style="font-size:small;"><span style="font-family:宋體;mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">雙相不鏽鋼薄壁管全部采用</span><span style="font-family:'Times New Roman';"><span lang="EN-US">GTAW</span></span><span style="font-family:宋體;mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">焊接,直流正極性。</span></span><span lang="EN-US"><br /> <span style="font-family:'Times New Roman';font-size:small;"> 2.3&nbsp; &nbsp; </span></span><span style="font-family:宋體;mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;"><span style="font-size:small;">焊接設備</span></span><span lang="EN-US"><br /> <span style="font-family:'Times New Roman';font-size:small;"> </span></span><span style="font-size:small;"><span style="font-family:宋體;mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">焊機采用高頻引弧焊機,直流正極性,鎢極直徑</span><span style="font-family:'Times New Roman';"><span lang="EN-US">Φ2.5mm</span></span><span style="font-family:宋體;mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">,鎢極端頭用磨光機磨出錐形,采用大噴嘴。</span></span><span lang="EN-US"><br /> <span style="font-family:'Times New Roman';font-size:small;"> 2.4&nbsp; &nbsp; </span></span><span style="font-family:宋體;mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;"><span style="font-size:small;">氣體保護</span></span><span lang="EN-US"><br /> <span style="font-family:'Times New Roman';font-size:small;"> </span></span><span style="font-size:small;"><span style="font-family:宋體;mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">焊接保護氣體采用混合氣體</span><span style="font-family:'Times New Roman';"><span lang="EN-US">Ar97.5%+N2.5% </span></span><span style="font-family:宋體;mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">進行保護,保護氣采用成品混合氣,要求生產的成品混合比為</span><span style="font-family:'Times New Roman';"><span lang="EN-US">Ar97.5%+N2.5%</span></span><span style="font-family:宋體;mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">,由於混合氣體中</span><span style="font-family:'Times New Roman';"><span lang="EN-US">Ar</span></span><span style="font-family:宋體;mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">比</span><span style="font-family:'Times New Roman';"><span lang="EN-US">N</span></span><span style="font-family:宋體;mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">多,放置一段時間後將會產生分層,影響氣體保護效果,現場所采用搖勺或加氣體分配器進行配比,確保氣體保護質量。</span></span><span lang="EN-US"><br /> <span style="font-family:'Times New Roman';font-size:small;"> 2.5&nbsp; &nbsp; </span></span><span style="font-family:宋體;mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;"><span style="font-size:small;">環境要求</span></span><span lang="EN-US"><br /> <span style="font-family:'Times New Roman';font-size:small;"> </span></span><span style="font-size:small;"><span style="font-family:宋體;mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">雙相不鏽鋼焊接要求環境清潔。無鐵離子汙染,預置工作將在室內進行,地麵采用膠皮隔離、安裝必須做好環境保護。采用防風防塵設施,環境溫度</span><span style="font-family:'Times New Roman';"><span lang="EN-US">70</span></span><span style="font-family:宋體;mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">℃,相對溫度</span><span style="font-family:'Times New Roman';"><span lang="EN-US">≤90%</span></span><span style="font-family:宋體;mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">,所有與雙相鋼焊接坡口相接觸的,如:焊材、工具、手套等,都必須無鐵鏽汙染。坡口均采用坡口機加工,坡口角度為單邊</span><span style="font-family:'Times New Roman';"><span lang="EN-US">30°±2.5°</span></span><span style="font-family:宋體;mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">,鈍邊</span><span style="font-family:'Times New Roman';"><span lang="EN-US">0~ 0.5mm</span></span><span style="font-family:宋體;mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">,單麵坡口(見附圖),加工坡口不允許母材產生過燒變色;其兩側各</span><span style="font-family:'Times New Roman';"><span lang="EN-US">50mm</span></span><span style="font-family:宋體;mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">以內的內外表麵要進行嚴格清理,清理程序是磨光機打磨、丙酮(或無水乙醇)清洗,清洗後不能直接進行焊接作業,待坡口端麵晾乾後方可焊接作業;焊絲也用沾丙酮(或無水乙醇)的海綿擦拭乾淨。對鐵離子、水鏽、油、灰塵、油漆、記號筆印都必須清理乾淨,防止其影響化學成份和機械性能。另外,還要注意坡口形狀必須無凹凸和劃痕,這樣焊接時電弧在焊道的每一點上都能保證停留相同的時間,焊接線能量才能確保一致。</span></span><span lang="EN-US"><br /> <span style="font-family:'Times New Roman';font-size:small;"> 2.6&nbsp; &nbsp; </span></span><span style="font-family:宋體;mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;"><span style="font-size:small;">焊接措施</span></span><span lang="EN-US"><br /> <span style="font-family:'Times New Roman';font-size:small;"> </span></span><span style="font-size:small;"><span style="font-family:宋體;mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">儘量采用多層焊,因為後續焊道對前層焊道有熱處理作用,焊縫中的</span><span style="font-family:'Times New Roman';"><span lang="EN-US">δ</span></span><span style="font-family:宋體;mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">相進一步轉化為</span><span style="font-family:'Times New Roman';"><span lang="EN-US">γ</span></span><span style="font-family:宋體;mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">相,使焊接接頭的組織和性能顯著改善,而後一道焊縫處於非工作介質麵,因為對焊接接頭影響不大,保護氣采用</span><span style="font-family:'Times New Roman';"><span lang="EN-US">Ar97.5%+N2.5%</span></span><span style="font-family:宋體;mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">。因為焊接根部保護氣體中加氮氣增加焊縫金屬氮量,由於采用多層焊工藝,焊接材料中含</span><span style="font-family:'Times New Roman';"><span lang="EN-US">N</span></span><span style="font-family:宋體;mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">量與母材相當,而後一道焊縫處於非工作介質麵,因為對焊接接頭影響不大,采用合適的線能量焊接,使焊接接頭得到足夠的</span><span style="font-family:'Times New Roman';"><span lang="EN-US">γ</span></span><span style="font-family:宋體;mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">相,使</span><span style="font-family:'Times New Roman';"><span lang="EN-US">Cγ</span></span><span style="font-family:宋體;mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">、</span><span style="font-family:'Times New Roman';"><span lang="EN-US">N1 </span></span><span style="font-family:宋體;mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">和</span><span style="font-family:'Times New Roman';"><span lang="EN-US">M</span></span><span style="font-family:宋體;mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">有足夠的時間擴散。</span></span><span lang="EN-US"><br /> <span style="font-family:'Times New Roman';font-size:small;"> 2.7&nbsp; &nbsp; </span></span><span style="font-family:宋體;mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;"><span style="font-size:small;">坡口的組對及點焊</span></span><span lang="EN-US"><br /> <span style="font-family:'Times New Roman';font-size:small;"> </span></span><span style="font-size:small;"><span style="font-family:宋體;mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">坡口組對前應仔細檢查坡口管徑是否相同,錯邊應控製在</span><span style="font-family:'Times New Roman';"><span lang="EN-US">0.5~1mm</span></span><span style="font-family:宋體;mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">之間,並用磨光機打磨清理坡口及坡口正反麵兩側</span><span style="font-family:'Times New Roman';"><span lang="EN-US">50mm</span></span><span style="font-family:宋體;mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">以內的表麵,並用丙酮擦試乾淨,坡口打磨時不允許使母材產生過熱變色。點焊時,應采用與正式的焊接工藝相同的參數,點焊長度為</span><span style="font-family:'Times New Roman';"><span lang="EN-US">7~8mm</span></span><span style="font-family:宋體;mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">,高度為</span><span style="font-family:'Times New Roman';"><span lang="EN-US">2~ 3mm</span></span><span style="font-family:宋體;mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">,點焊點應為過橋型式,不應焊透,以防內部氧化,點焊電流不宜過大,點焊點位置應在組對管子的上部及兩側,點固三點,從第四點起焊,當焊到點焊時,將點固點打磨清理乾淨,焊縫組對間隙應控製在</span><span style="font-family:'Times New Roman';"><span lang="EN-US">2~2.5mm</span></span><span style="font-family:宋體;mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">,間隙不應過大,並留有</span><span style="font-family:'Times New Roman';"><span lang="EN-US">0~0.5mm</span></span><span style="font-family:宋體;mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">的鈍邊。</span></span><span lang="EN-US"><br /> <span style="font-family:'Times New Roman';font-size:small;"> 2.8&nbsp; &nbsp; </span></span><span style="font-family:宋體;mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;"><span style="font-size:small;">雙相不鏽鋼的焊接操作</span></span><span lang="EN-US"><br /> <span style="font-family:'Times New Roman';font-size:small;"> </span></span><span style="font-size:small;"><span style="font-family:宋體;mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">雙相不鏽鋼焊接時,應采用正反麵氣體保護焊,正麵背麵都應采用混合氣體</span><span style="font-family:'Times New Roman';"><span lang="EN-US">Ar97.5%+N2.5% </span></span><span style="font-family:宋體;mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">進行保護,焊接前不得在焊件表麵引弧和試驗電流,焊接時應按指定的焊接作業指導書進行施焊。在焊接前,管子兩端用布或膠皮封好,並留有進氣孔和排氣孔,焊縫間隙用膠布貼好,並留有</span><span style="font-family:'Times New Roman';"><span lang="EN-US">20~30mm</span></span><span style="font-family:宋體;mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">的長度,使管子內部的空氣能夠排出,確保焊縫內部的氣體保護效果。焊接時,焊槍不宜擺動,手法要穩,嚴格控製線能量,儘量采用小焊絲,嚴格控製電流,弧長儘量壓低控製電壓,儘量用大噴嘴,提高氣體保護效果,降底</span><span style="font-family:'Times New Roman';"><span lang="EN-US">O</span></span><span style="font-family:宋體;mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">、</span><span style="font-family:'Times New Roman';"><span lang="EN-US">H</span></span><span style="font-family:宋體;mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">汙染;引、收弧避開點焊點,防止產生二次</span><span style="font-family:'Times New Roman';"><span lang="EN-US">γ</span></span><span style="font-family:宋體;mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">和</span><span style="font-family:'Times New Roman';"><span lang="EN-US">δ</span></span><span style="font-family:宋體;mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">相,引弧點必須在焊道內進行,不能在母材表麵引弧,防止</span><span style="font-family:'Times New Roman';"><span lang="EN-US">F</span></span><span style="font-family:宋體;mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">量超標;點焊點打磨後,封底焊焊接過程中通過觀察焊道顏色來確定焊接氣體保護效果,采用混合氣體施焊時焊道好為金黃色,稍差一些為黃銅色,儘量減少焊縫發藍,杜絕焊道發灰和發黑,並嚴格控製層間溫度,控製熔池在紅熱狀態下停留時間。一般來講,隻要保證在</span><span style="font-family:'Times New Roman';"><span lang="EN-US">5~15s</span></span><span style="font-family:宋體;mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">時間內熔池由紅轉至常規顏色,就能達到要求。打底焊的層間溫度</span><span style="font-family:'Times New Roman';"><span lang="EN-US">≤100</span></span><span style="font-family:宋體;mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">℃,可用遠紅外激光測溫儀測量。當層間溫度<</span><span style="font-family:'Times New Roman';"><span lang="EN-US">100</span></span><span style="font-family:宋體;mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">℃時,才能進行下一層焊接,焊接電流不能超過打底焊的電流,焊**層必須認真清理前一層焊道,除消除雜質外,連氧化色也需磨去,焊縫內部餘高應控製在</span><span style="font-family:'Times New Roman';"><span lang="EN-US">0.5 ~1mm</span></span><span style="font-family:宋體;mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">;焊縫收弧時應將弧坑填滿,多層焊的層間接頭應相互錯開,如果焊接作業時不慎出現夾鎢時,應停止焊接作業,用磨光機消除鎢點,鎢極端部重新磨尖,達到要求後方可重新進行焊接作業,要求與開始焊接作業相同。</span></span><span lang="EN-US"><br /> <span style="font-family:'Times New Roman';font-size:small;"> 2.9&nbsp; &nbsp; </span></span><span style="font-family:宋體;mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;"><span style="font-size:small;">焊後清理和焊接檢驗</span></span><span lang="EN-US"><br /> <span style="font-family:'Times New Roman';font-size:small;"> </span></span><span style="font-size:small;"><span style="font-family:宋體;mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">雙相不鏽鋼的焊後清理也很重要,氧化色必須**,因為氧化色下麵就是貧鉻層,若不去除將會導致耐蝕性能下降,去除氧化色可用專用不鏽鋼絲刷趁熱擦刷;也可用酸或酸洗膏清洗。去除焊接飛濺,打磨收起弧點,去除咬邊和粗毛刺。可用較細的砂輪片或拋光砂輪片研磨,杜絕粗糙打磨痕跡,否則易造成縫隙腐蝕;油汙、著色劑、色筆印、灰塵均有可能成為孔腐蝕和縫隙腐蝕的起始點,可用硝酸</span><span style="font-family:'Times New Roman';"><span lang="EN-US">+</span></span><span style="font-family:宋體;mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">氫氟酸清洗,然後清水衝洗乾淨;焊工應對焊道表麵進行清理,要求外觀良好,寬度以每邊蓋過坡口邊緣</span><span style="font-family:'Times New Roman';"><span lang="EN-US">2mm</span></span><span style="font-family:宋體;mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">為宜,角焊縫的焊腳高度符合設計規定外形平穩過渡,焊縫不允許咬邊、裂紋、未焊透、氣孔、夾雜存在。射線探傷方法按《壓力容器無損檢測》</span><span style="font-family:'Times New Roman';"><span lang="EN-US">JB4730-g4</span></span><span style="font-family:宋體;mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">執行,所有焊道必須進行硬度測定,測定母材</span><span style="font-family:'Times New Roman';"><span lang="EN-US">-HAZ-</span></span><span style="font-family:宋體;mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">焊道</span><span style="font-family:'Times New Roman';"><span lang="EN-US">-HAZ-</span></span><span style="font-family:宋體;mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">母材。</span></span><span lang="EN-US"><br /> <span style="font-family:'Times New Roman';font-size:small;"> 3&nbsp; &nbsp; </span></span><span style="font-family:宋體;mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;"><span style="font-size:small;">結束語</span></span><span lang="EN-US"><br /> <span style="font-family:'Times New Roman';font-size:small;"> </span></span><span style="font-size:small;"><span style="font-family:宋體;mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">采用上述焊接工藝和焊接操作要領,在儀征化纖</span><span style="font-family:'Times New Roman';"><span lang="EN-US">45</span></span><span style="font-family:宋體;mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">萬噸</span><span style="font-family:'Times New Roman';"><span lang="EN-US">/</span></span><span style="font-family:宋體;mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">年</span><span style="font-family:'Times New Roman';"><span lang="EN-US">PTA</span></span><span style="font-family:宋體;mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">裝置施工過程中進行雙相不鏽鋼薄壁管現場施焊,取得了焊縫連續</span><span style="font-family:'Times New Roman';"><span lang="EN-US">5</span></span><span style="font-family:宋體;mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">個月</span><span style="font-family:'Times New Roman';"><span lang="EN-US">RT100%</span></span><span style="font-family:宋體;mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">合格,年度雙相不鏽鋼焊接接頭綜合合格率達到</span><span style="font-family:'Times New Roman';"><span lang="EN-US">99%</span></span><span style="font-family:宋體;mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">以上的施焊業績。</span></span> </p> <span style="font-family:宋體;font-size:small;"> </span>

西安雙相不鏽鋼管的焊接要求

在石油化工裝置中一種新型鋼材-雙相不鏽鋼的應用越來越多。因為雙相不鏽鋼的屈服強度是普通不鏽鋼的2倍,抗腐蝕性能(特彆是在腐蝕性介質中)明顯優於普通不鏽鋼,在石油化工裝置施工中多用在很重要的位置。因此,一般雙相不鏽鋼的焊縫要求100%RT檢驗,對其焊接接頭的綜合性能的要求也高於一般奧氏體不鏽鋼。所以,必須選派焊接經驗豐富的奧氏體不鏽鋼焊工,經培訓和考試合格後,才能持證上崗進行焊接作業。
1   
焊接性分析
雙相不鏽鋼焊接時,焊接熱影響區(HAZ 存在高溫區和低溫區,低溫區基本處於δ+γ(鐵素體+奧氏體)平衡組織,而高溫區幾乎為單相δ組織,因為焊縫根部和表麵N的擴散,導致靠近焊縫表麵的部位,由於N的損失,鐵素體增加,從而促進氮化物的產生,使焊接接頭性能惡化,焊接采用高線能量時,可以得到較多的γ相,鐵素體含量低會促進δ相產生,所以容易產生δ相和粗晶組織;線能量較低時,得不到足夠的γ相。如果焊接金屬中δ相過多,N很容易與形成化合物,而且析出二次γ變為針狀和羽毛狀,具有魏氏體組織特性,導致焊接接頭力學性能和耐腐蝕性下降。雙相鋼一般不會產生δ相,但如果焊接線能量較高,導致使焊接頭塑性大幅度下降。
2   
焊接工藝
2.1   
工藝參數及電特性(見表2
2.2   
焊接方法
雙相不鏽鋼薄壁管全部采用GTAW焊接,直流正極性。
2.3   
焊接設備
焊機采用高頻引弧焊機,直流正極性,鎢極直徑Φ2.5mm,鎢極端頭用磨光機磨出錐形,采用大噴嘴。
2.4   
氣體保護
焊接保護氣體采用混合氣體Ar97.5%+N2.5% 進行保護,保護氣采用成品混合氣,要求生產的成品混合比為Ar97.5%+N2.5%,由於混合氣體中ArN多,放置一段時間後將會產生分層,影響氣體保護效果,現場所采用搖勺或加氣體分配器進行配比,確保氣體保護質量。
2.5   
環境要求
雙相不鏽鋼焊接要求環境清潔。無鐵離子汙染,預置工作將在室內進行,地麵采用膠皮隔離、安裝必須做好環境保護。采用防風防塵設施,環境溫度70℃,相對溫度≤90%,所有與雙相鋼焊接坡口相接觸的,如:焊材、工具、手套等,都必須無鐵鏽汙染。坡口均采用坡口機加工,坡口角度為單邊30°±2.5°,鈍邊0~ 0.5mm,單麵坡口(見附圖),加工坡口不允許母材產生過燒變色;其兩側各50mm以內的內外表麵要進行嚴格清理,清理程序是磨光機打磨、丙酮(或無水乙醇)清洗,清洗後不能直接進行焊接作業,待坡口端麵晾乾後方可焊接作業;焊絲也用沾丙酮(或無水乙醇)的海綿擦拭乾淨。對鐵離子、水鏽、油、灰塵、油漆、記號筆印都必須清理乾淨,防止其影響化學成份和機械性能。另外,還要注意坡口形狀必須無凹凸和劃痕,這樣焊接時電弧在焊道的每一點上都能保證停留相同的時間,焊接線能量才能確保一致。
2.6   
焊接措施
儘量采用多層焊,因為後續焊道對前層焊道有熱處理作用,焊縫中的δ相進一步轉化為γ相,使焊接接頭的組織和性能顯著改善,而後一道焊縫處於非工作介質麵,因為對焊接接頭影響不大,保護氣采用Ar97.5%+N2.5%。因為焊接根部保護氣體中加氮氣增加焊縫金屬氮量,由於采用多層焊工藝,焊接材料中含N量與母材相當,而後一道焊縫處於非工作介質麵,因為對焊接接頭影響不大,采用合適的線能量焊接,使焊接接頭得到足夠的γ相,使N1 M有足夠的時間擴散。
2.7   
坡口的組對及點焊
坡口組對前應仔細檢查坡口管徑是否相同,錯邊應控製在0.5~1mm之間,並用磨光機打磨清理坡口及坡口正反麵兩側50mm以內的表麵,並用丙酮擦試乾淨,坡口打磨時不允許使母材產生過熱變色。點焊時,應采用與正式的焊接工藝相同的參數,點焊長度為7~8mm,高度為2~ 3mm,點焊點應為過橋型式,不應焊透,以防內部氧化,點焊電流不宜過大,點焊點位置應在組對管子的上部及兩側,點固三點,從第四點起焊,當焊到點焊時,將點固點打磨清理乾淨,焊縫組對間隙應控製在2~2.5mm,間隙不應過大,並留有0~0.5mm的鈍邊。
2.8   
雙相不鏽鋼的焊接操作
雙相不鏽鋼焊接時,應采用正反麵氣體保護焊,正麵背麵都應采用混合氣體Ar97.5%+N2.5% 進行保護,焊接前不得在焊件表麵引弧和試驗電流,焊接時應按指定的焊接作業指導書進行施焊。在焊接前,管子兩端用布或膠皮封好,並留有進氣孔和排氣孔,焊縫間隙用膠布貼好,並留有20~30mm的長度,使管子內部的空氣能夠排出,確保焊縫內部的氣體保護效果。焊接時,焊槍不宜擺動,手法要穩,嚴格控製線能量,儘量采用小焊絲,嚴格控製電流,弧長儘量壓低控製電壓,儘量用大噴嘴,提高氣體保護效果,降底OH汙染;引、收弧避開點焊點,防止產生二次γδ相,引弧點必須在焊道內進行,不能在母材表麵引弧,防止F量超標;點焊點打磨後,封底焊焊接過程中通過觀察焊道顏色來確定焊接氣體保護效果,采用混合氣體施焊時焊道好為金黃色,稍差一些為黃銅色,儘量減少焊縫發藍,杜絕焊道發灰和發黑,並嚴格控製層間溫度,控製熔池在紅熱狀態下停留時間。一般來講,隻要保證在5~15s時間內熔池由紅轉至常規顏色,就能達到要求。打底焊的層間溫度≤100℃,可用遠紅外激光測溫儀測量。當層間溫度<100℃時,才能進行下一層焊接,焊接電流不能超過打底焊的電流,焊**層必須認真清理前一層焊道,除消除雜質外,連氧化色也需磨去,焊縫內部餘高應控製在0.5 ~1mm;焊縫收弧時應將弧坑填滿,多層焊的層間接頭應相互錯開,如果焊接作業時不慎出現夾鎢時,應停止焊接作業,用磨光機消除鎢點,鎢極端部重新磨尖,達到要求後方可重新進行焊接作業,要求與開始焊接作業相同。
2.9   
焊後清理和焊接檢驗
雙相不鏽鋼的焊後清理也很重要,氧化色必須**,因為氧化色下麵就是貧鉻層,若不去除將會導致耐蝕性能下降,去除氧化色可用專用不鏽鋼絲刷趁熱擦刷;也可用酸或酸洗膏清洗。去除焊接飛濺,打磨收起弧點,去除咬邊和粗毛刺。可用較細的砂輪片或拋光砂輪片研磨,杜絕粗糙打磨痕跡,否則易造成縫隙腐蝕;油汙、著色劑、色筆印、灰塵均有可能成為孔腐蝕和縫隙腐蝕的起始點,可用硝酸+氫氟酸清洗,然後清水衝洗乾淨;焊工應對焊道表麵進行清理,要求外觀良好,寬度以每邊蓋過坡口邊緣2mm為宜,角焊縫的焊腳高度符合設計規定外形平穩過渡,焊縫不允許咬邊、裂紋、未焊透、氣孔、夾雜存在。射線探傷方法按《壓力容器無損檢測》JB4730-g4執行,所有焊道必須進行硬度測定,測定母材-HAZ-焊道-HAZ-母材。
3   
結束語
采用上述焊接工藝和焊接操作要領,在儀征化纖45萬噸/PTA裝置施工過程中進行雙相不鏽鋼薄壁管現場施焊,取得了焊縫連續5個月RT100%合格,年度雙相不鏽鋼焊接接頭綜合合格率達到99%以上的施焊業績。

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