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不鏽鋼管的焊接方法

日期:2024-07-04 17:37
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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:"Times New Roman";mso-hansi-font-family:"Times New Roman";"><span style="font-size:small;">不鏽鋼管的焊接方法</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:"Times New Roman";mso-hansi-font-family:"Times New Roman";">不鏽鋼管的焊接通常由打底焊、填充焊、蓋麵焊幾部分組成。不鏽鋼管打底焊是不鏽鋼管焊接中*關鍵的一環,它不僅關係到工程的質量,而且關係到工程的進度,目前不鏽鋼打底分為背麵充氬和不充氬兩種工藝。背麵充氬保護又分為實芯焊絲</span><span style="font-family:'Times New Roman';"><span lang="EN-US">+TIG</span></span><span style="font-family:宋體;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:"Times New Roman";">工藝和實芯焊絲</span><span style="font-family:'Times New Roman';"><span lang="EN-US">+TIG+</span></span><span style="font-family:宋體;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:"Times New Roman";">水溶性紙工藝兩種;背麵不充氬保護又分為藥芯焊絲打底焊和焊棒</span><span style="font-family:'Times New Roman';"><span lang="EN-US">(</span></span><span style="font-family:宋體;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:"Times New Roman";">藥皮焊絲</span><span style="font-family:'Times New Roman';"><span lang="EN-US">)</span></span><span style="font-family:宋體;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:"Times New Roman";">打底</span><span style="font-family:'Times New Roman';"><span lang="EN-US">TIG</span></span><span style="font-family:宋體;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:"Times New Roman";">焊。</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:"Times New Roman";mso-hansi-font-family:"Times New Roman";">不鏽鋼管的焊接通常由打底焊、填充焊、蓋麵焊幾部分組成。不鏽鋼管打底焊是不鏽鋼管焊接中*關鍵的一環,它不僅關係到工程的質量,而且關係到工程的進度,目前不鏽鋼打底分為背麵充氬和不充氬兩種工藝。背麵充氬保護又分為實芯焊絲</span><span style="font-family:'Times New Roman';"><span lang="EN-US">+TIG</span></span><span style="font-family:宋體;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:"Times New Roman";">工藝和實芯焊絲</span><span style="font-family:'Times New Roman';"><span lang="EN-US">+TIG+</span></span><span style="font-family:宋體;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:"Times New Roman";">水溶性紙工藝兩種;背麵不充氬保護又分為藥芯焊絲打底焊和焊棒</span><span style="font-family:'Times New Roman';"><span lang="EN-US">(</span></span><span style="font-family:宋體;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:"Times New Roman";">藥皮焊絲</span><span style="font-family:'Times New Roman';"><span lang="EN-US">)</span></span><span style="font-family:宋體;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:"Times New Roman";">打底</span><span style="font-family:'Times New Roman';"><span lang="EN-US">TIG</span></span><span style="font-family:宋體;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:"Times New Roman";">焊。</span></span> </p> <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:"Times New Roman";mso-hansi-font-family:"Times New Roman";"><span style="font-size:small;">不鏽鋼打底焊采用的幾種方法</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:"Times New Roman";mso-hansi-font-family:"Times New Roman";">不鏽鋼打底焊通常采用</span><span style="font-family:'Times New Roman';"><span lang="EN-US">TIG</span></span><span style="font-family:宋體;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:"Times New Roman";">工藝,根據現場的實際情況,我們可采用以下四種方法進行打底焊。</span></span> </p> <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:"Times New Roman";mso-hansi-font-family:"Times New Roman";"><span style="font-size:small;">①背麵采用堵板進行封堵通氣保護的方法;</span></span> </p> <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:"Times New Roman";mso-hansi-font-family:"Times New Roman";"><span style="font-size:small;">②隻采用可溶性紙或采用可溶性紙與堵板相結合進行封堵通氣保護的方法;</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:"Times New Roman";mso-hansi-font-family:"Times New Roman";">③采用藥芯焊絲打底</span><span style="font-family:'Times New Roman';"><span lang="EN-US">TIG</span></span><span style="font-family:宋體;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:"Times New Roman";">焊。</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:"Times New Roman";mso-hansi-font-family:"Times New Roman";">④采用藥皮焊絲(自保護焊絲)打底</span><span style="font-family:'Times New Roman';"><span lang="EN-US">TIG</span></span><span style="font-family:宋體;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:"Times New Roman";">焊。</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:'Times New Roman';"><span lang="EN-US">1.</span></span><span style="font-family:宋體;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:"Times New Roman";">背麵采用堵板進行封堵通氣保護的方法</span><span style="font-family:'Times New Roman';"><span lang="EN-US">(</span></span><span style="font-family:宋體;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:"Times New Roman";">即實芯焊絲</span><span style="font-family:'Times New Roman';"><span lang="EN-US">+TIG</span></span><span style="font-family:宋體;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:"Times New Roman";">)</span></span> </p> <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:"Times New Roman";mso-hansi-font-family:"Times New Roman";"><span style="font-size:small;">不鏽鋼管道預製時,焊口通常可進行轉動焊接,通氣非常容易,這時通常采用堵板對管道內焊口兩側進行封堵通氣進行保護的方法進行打底焊(見圖表一),同時外側用膠粘布進行封堵。</span></span> </p> <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:"Times New Roman";mso-hansi-font-family:"Times New Roman";"><span style="font-size:small;">焊接時,應采用提前通氣,滯後停氣的工藝,外側膠粘布邊焊邊撕去,由於堵板為膠皮與白鐵皮組成,不易損壞,所以這種焊接方法能很好的保證焊縫內側充滿氬氣及保證其純度,從而有效地保證焊縫內側金屬不被氧化,保證了焊縫打底焊的質量。</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:'Times New Roman';"><span lang="EN-US">2.</span></span><span style="font-family:宋體;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:"Times New Roman";">隻采用可溶性紙或采用可溶性紙與堵板相結合進行封堵通氣保護的方法(即實芯焊絲</span><span style="font-family:'Times New Roman';"><span lang="EN-US">+TIG+</span></span><span style="font-family:宋體;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:"Times New Roman";">水溶性紙)</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:"Times New Roman";mso-hansi-font-family:"Times New Roman";">不鏽鋼管道固定口安裝焊接時,內側通氣比較困難,有的一側較易進行封堵,在這種情況下,可采用水溶性紙</span><span style="font-family:'Times New Roman';"><span lang="EN-US">+</span></span><span style="font-family:宋體;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:"Times New Roman";">堵板進行封堵。即易通氣、好拆除的一側用堵板進行封堵,不易通氣、不好拆除堵板的一側用水溶性紙進行封堵,同時外側用膠粘布粘貼焊縫進行封堵(見圖表二)。</span></span> </p> <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:"Times New Roman";mso-hansi-font-family:"Times New Roman";"><span style="font-size:small;">不鏽鋼固定口焊接時,在很多情況下會出現焊縫兩側都無法通氣,這時如何保證焊縫內側充氬保護就成為了一個難題,在現場實際施工中,我們采用焊縫兩側用水溶性紙進行封堵,從焊縫中心通氣、外側用膠粘布粘貼進行封堵的方法(見圖表三),成功的解決了上述難題。</span></span> </p> <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:"Times New Roman";mso-hansi-font-family:"Times New Roman";"><span style="font-size:small;">采用水溶性紙封堵通氣時,由於從焊縫中心通氣,因此在*後的封口環節,應迅速拔掉通氣管,利用裡麵的剩餘氬氣進行保護,快速打完底,封好口。</span></span> </p> <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:"Times New Roman";mso-hansi-font-family:"Times New Roman";"><span style="font-size:small;">采用這種方法,應注意水溶性紙應采用雙層的,一定要粘貼好,否則容易造成水溶性紙損壞、脫落而使內側焊縫失去氬氣的保護,產生氧化,導致焊口割開重新施焊,既保證不了焊接質量,又嚴重影響了工期,因此焊接以前應嚴格檢查,粘貼好水溶性紙。</span></span> </p> <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:"Times New Roman";mso-hansi-font-family:"Times New Roman";"><span style="font-size:small;">在很多施工現場,我們都采用了此種焊接方法進行打底,其質量能得到有效的保證,同時也有一定的施工難度,因此應選用仔細、技術熟練的焊工擔任此項工作。</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:'Times New Roman';"><span lang="EN-US">3.</span></span><span style="font-family:宋體;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:"Times New Roman";">背麵不進行通氬氣保護,采用藥芯焊絲</span><span style="font-family:'Times New Roman';"><span lang="EN-US">+TIG</span></span><span style="font-family:宋體;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:"Times New Roman";">工藝</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:"Times New Roman";mso-hansi-font-family:"Times New Roman";">該方法在我國應用已有數年,現已生產出</span><span style="font-family:'Times New Roman';"><span lang="EN-US">E308T1-1</span></span><span style="font-family:宋體;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:"Times New Roman";">、</span><span style="font-family:'Times New Roman';"><span lang="EN-US">E308LT1-1</span></span><span style="font-family:宋體;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:"Times New Roman";">、</span><span style="font-family:'Times New Roman';"><span lang="EN-US">E309T1-1</span></span><span style="font-family:宋體;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:"Times New Roman";">、</span><span style="font-family:'Times New Roman';"><span lang="EN-US">E309LT1-1</span></span><span style="font-family:宋體;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:"Times New Roman";">、</span><span style="font-family:'Times New Roman';"><span lang="EN-US">347T1-1</span></span><span style="font-family:宋體;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:"Times New Roman";">、</span><span style="font-family:'Times New Roman';"><span lang="EN-US">E316T1-1</span></span><span style="font-family:宋體;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:"Times New Roman";">、</span><span style="font-family:'Times New Roman';"><span lang="EN-US">E316LT1-1</span></span><span style="font-family:宋體;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:"Times New Roman";">等藥芯焊絲,並已應用於現場的焊接,取得了較好的經濟效益。</span></span> </p> <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:"Times New Roman";mso-hansi-font-family:"Times New Roman";"><span style="font-size:small;">由於背麵不充氬,其優點顯而易見,主要表現為高效、簡便、成本低,適宜於施工現場安裝。但藥芯焊絲由於其結構特點,操作時對焊工的要求較高,其送絲速度快,送絲準確度要求高,掌握有一定難度,焊工應經專門培訓,技術熟練後方可參加焊接,在南京揚巴及國外工地,我們應用此方法,成功地解決了碰頭口、返修口無法通氬氣的問題。</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:'Times New Roman';"><span lang="EN-US">4.</span></span><span style="font-family:宋體;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:"Times New Roman";">背麵不進行通氬氣保護,采用藥皮焊絲(自保護藥芯焊絲)</span><span style="font-family:'Times New Roman';"><span lang="EN-US">+TIG</span></span><span style="font-family:宋體;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:"Times New Roman";">工藝</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:'Times New Roman';"><span lang="EN-US">20</span></span><span style="font-family:宋體;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:"Times New Roman";">世紀</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:"Times New Roman";mso-hansi-font-family:"Times New Roman";">年代,日本的神鋼等公司研製出了打底焊絲,近年來,我國也已研製開發出了不鏽鋼打底焊絲(即藥皮焊絲,如</span><span style="font-family:'Times New Roman';"><span lang="EN-US">TGF308</span></span><span style="font-family:宋體;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:"Times New Roman";">、</span><span style="font-family:'Times New Roman';"><span lang="EN-US">TGF308L</span></span><span style="font-family:宋體;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:"Times New Roman";">、</span><span style="font-family:'Times New Roman';"><span lang="EN-US">TGF309</span></span><span style="font-family:宋體;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:"Times New Roman";">、</span><span style="font-family:'Times New Roman';"><span lang="EN-US">TGF316L</span></span><span style="font-family:宋體;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:"Times New Roman";">、</span><span style="font-family:'Times New Roman';"><span lang="EN-US">TGF347</span></span><span style="font-family:宋體;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:"Times New Roman";">等),並應用於實際施工中,取得了良好的效果,在烏石化擴能改造項目我們就成功的運用了此方法。</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:"Times New Roman";mso-hansi-font-family:"Times New Roman";">不鏽鋼打底焊絲</span><span style="font-family:'Times New Roman';"><span lang="EN-US">+TIG</span></span><span style="font-family:宋體;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:"Times New Roman";">工藝的保護機理是背麵焊縫利用焊絲熔化產生的熔渣和其合金元素的冶金反應來進行保護,正麵焊縫依靠氬氣、渣和合金元素進行保護。</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:"Times New Roman";mso-hansi-font-family:"Times New Roman";">采用此種工藝,應注意以下操作要點:焊接過程中,焊把、焊絲、焊件之間保持正確的夾角,理想的焊把噴嘴後傾角為</span><span style="font-family:'Times New Roman';"><span lang="EN-US">70°—80°</span></span><span style="font-family:宋體;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:"Times New Roman";">,焊絲與焊件表麵夾角為</span><span style="font-family:'Times New Roman';"><span lang="EN-US">15°—20°</span></span><span style="font-family:宋體;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:"Times New Roman";">;正確控製熔池溫度,通過改變焊把與焊件的夾角、改變焊接速度等來改變熔池溫度,從而保證焊縫成形美觀(寬窄一致、不出現內凹、過凸等缺陷);</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:"Times New Roman";mso-hansi-font-family:"Times New Roman";">操作時,電流應比焊實芯焊絲時稍大,焊把應稍作擺動,以使鐵水和熔化的藥皮加速分離,便於觀察熔池和控製是否焊透;填充焊絲時,*好送到熔池的</span><span style="font-family:'Times New Roman';"><span lang="EN-US">1/2</span></span><span style="font-family:宋體;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:"Times New Roman";">處,並向內稍壓一下,以此手法來保證根部焊透、並防止出現內凹;</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:"Times New Roman";mso-hansi-font-family:"Times New Roman";">焊接過程中,焊絲應有規則的送入、取出,並保證焊絲始終處於氬氣的保護下,以免焊絲端部被氧化,影響焊接質量;注意起弧、收弧處的焊接質量,起弧處應將點焊處打磨成</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:"Times New Roman";mso-hansi-font-family:"Times New Roman";">緩坡,收弧時應注意產生弧坑、縮孔等缺陷。</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:"Times New Roman";mso-hansi-font-family:"Times New Roman";">采用藥皮焊絲打底焊,焊縫內部不用通氬氣,焊工操作起來簡便、快捷,具有高效、低成本的特點,同時也能很好地保證焊接質量(在烏石化擴能改造項目,我們采用此法焊接碰頭口、返修口共</span><span style="font-family:'Times New Roman';"><span lang="EN-US">28</span></span><span style="font-family:宋體;mso-ascii-font-family:"Times New Roman";mso-hansi-font-family:"Times New Roman";">道,焊接一次透視合格率</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:"Times New Roman";mso-hansi-font-family:"Times New Roman";">),值得我們推廣使用。</span></span> </p> <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:"Times New Roman";mso-hansi-font-family:"Times New Roman";"><span style="font-size:small;">上麵四種不鏽鋼打底焊方法各有優缺點,在實際施工中,我們應根據現場的具體條件,既要考慮施工成本的高低,又要考慮焊接質量及施工進度,合理地選擇施工工藝。</span></span> </p> <span style="font-family:宋體;font-size:small;"> </span> <p style="margin:0cm 0cm 0pt;"> <span lang="EN-US"><span style="font-family:'Times New Roman';font-size:small;"> </span></span> </p> <span style="font-family:宋體;font-size:small;"> </span>

不鏽鋼管的焊接方法

不鏽鋼管的焊接通常由打底焊、填充焊、蓋麵焊幾部分組成。不鏽鋼管打底焊是不鏽鋼管焊接中*關鍵的一環,它不僅關係到工程的質量,而且關係到工程的進度,目前不鏽鋼打底分為背麵充氬和不充氬兩種工藝。背麵充氬保護又分為實芯焊絲+TIG工藝和實芯焊絲+TIG+水溶性紙工藝兩種;背麵不充氬保護又分為藥芯焊絲打底焊和焊棒(藥皮焊絲)打底TIG焊。

不鏽鋼管的焊接通常由打底焊、填充焊、蓋麵焊幾部分組成。不鏽鋼管打底焊是不鏽鋼管焊接中*關鍵的一環,它不僅關係到工程的質量,而且關係到工程的進度,目前不鏽鋼打底分為背麵充氬和不充氬兩種工藝。背麵充氬保護又分為實芯焊絲+TIG工藝和實芯焊絲+TIG+水溶性紙工藝兩種;背麵不充氬保護又分為藥芯焊絲打底焊和焊棒(藥皮焊絲)打底TIG焊。

不鏽鋼打底焊采用的幾種方法

不鏽鋼打底焊通常采用TIG工藝,根據現場的實際情況,我們可采用以下四種方法進行打底焊。

①背麵采用堵板進行封堵通氣保護的方法;

②隻采用可溶性紙或采用可溶性紙與堵板相結合進行封堵通氣保護的方法;

③采用藥芯焊絲打底TIG焊。

④采用藥皮焊絲(自保護焊絲)打底TIG焊。

1.背麵采用堵板進行封堵通氣保護的方法(即實芯焊絲+TIG

不鏽鋼管道預製時,焊口通常可進行轉動焊接,通氣非常容易,這時通常采用堵板對管道內焊口兩側進行封堵通氣進行保護的方法進行打底焊(見圖表一),同時外側用膠粘布進行封堵。

焊接時,應采用提前通氣,滯後停氣的工藝,外側膠粘布邊焊邊撕去,由於堵板為膠皮與白鐵皮組成,不易損壞,所以這種焊接方法能很好的保證焊縫內側充滿氬氣及保證其純度,從而有效地保證焊縫內側金屬不被氧化,保證了焊縫打底焊的質量。

2.隻采用可溶性紙或采用可溶性紙與堵板相結合進行封堵通氣保護的方法(即實芯焊絲+TIG+水溶性紙)

不鏽鋼管道固定口安裝焊接時,內側通氣比較困難,有的一側較易進行封堵,在這種情況下,可采用水溶性紙+堵板進行封堵。即易通氣、好拆除的一側用堵板進行封堵,不易通氣、不好拆除堵板的一側用水溶性紙進行封堵,同時外側用膠粘布粘貼焊縫進行封堵(見圖表二)。

不鏽鋼固定口焊接時,在很多情況下會出現焊縫兩側都無法通氣,這時如何保證焊縫內側充氬保護就成為了一個難題,在現場實際施工中,我們采用焊縫兩側用水溶性紙進行封堵,從焊縫中心通氣、外側用膠粘布粘貼進行封堵的方法(見圖表三),成功的解決了上述難題。

采用水溶性紙封堵通氣時,由於從焊縫中心通氣,因此在*後的封口環節,應迅速拔掉通氣管,利用裡麵的剩餘氬氣進行保護,快速打完底,封好口。

采用這種方法,應注意水溶性紙應采用雙層的,一定要粘貼好,否則容易造成水溶性紙損壞、脫落而使內側焊縫失去氬氣的保護,產生氧化,導致焊口割開重新施焊,既保證不了焊接質量,又嚴重影響了工期,因此焊接以前應嚴格檢查,粘貼好水溶性紙。

在很多施工現場,我們都采用了此種焊接方法進行打底,其質量能得到有效的保證,同時也有一定的施工難度,因此應選用仔細、技術熟練的焊工擔任此項工作。

3.背麵不進行通氬氣保護,采用藥芯焊絲+TIG工藝

該方法在我國應用已有數年,現已生產出E308T1-1E308LT1-1E309T1-1E309LT1-1347T1-1E316T1-1E316LT1-1等藥芯焊絲,並已應用於現場的焊接,取得了較好的經濟效益。

由於背麵不充氬,其優點顯而易見,主要表現為高效、簡便、成本低,適宜於施工現場安裝。但藥芯焊絲由於其結構特點,操作時對焊工的要求較高,其送絲速度快,送絲準確度要求高,掌握有一定難度,焊工應經專門培訓,技術熟練後方可參加焊接,在南京揚巴及國外工地,我們應用此方法,成功地解決了碰頭口、返修口無法通氬氣的問題。

4.背麵不進行通氬氣保護,采用藥皮焊絲(自保護藥芯焊絲)+TIG工藝

20世紀90年代,日本的神鋼等公司研製出了打底焊絲,近年來,我國也已研製開發出了不鏽鋼打底焊絲(即藥皮焊絲,如TGF308TGF308LTGF309TGF316LTGF347等),並應用於實際施工中,取得了良好的效果,在烏石化擴能改造項目我們就成功的運用了此方法。

不鏽鋼打底焊絲+TIG工藝的保護機理是背麵焊縫利用焊絲熔化產生的熔渣和其合金元素的冶金反應來進行保護,正麵焊縫依靠氬氣、渣和合金元素進行保護。

采用此種工藝,應注意以下操作要點:焊接過程中,焊把、焊絲、焊件之間保持正確的夾角,理想的焊把噴嘴後傾角為70°—80°,焊絲與焊件表麵夾角為15°—20°;正確控製熔池溫度,通過改變焊把與焊件的夾角、改變焊接速度等來改變熔池溫度,從而保證焊縫成形美觀(寬窄一致、不出現內凹、過凸等缺陷);

操作時,電流應比焊實芯焊絲時稍大,焊把應稍作擺動,以使鐵水和熔化的藥皮加速分離,便於觀察熔池和控製是否焊透;填充焊絲時,*好送到熔池的1/2處,並向內稍壓一下,以此手法來保證根部焊透、並防止出現內凹;

焊接過程中,焊絲應有規則的送入、取出,並保證焊絲始終處於氬氣的保護下,以免焊絲端部被氧化,影響焊接質量;注意起弧、收弧處的焊接質量,起弧處應將點焊處打磨成45°緩坡,收弧時應注意產生弧坑、縮孔等缺陷。

采用藥皮焊絲打底焊,焊縫內部不用通氬氣,焊工操作起來簡便、快捷,具有高效、低成本的特點,同時也能很好地保證焊接質量(在烏石化擴能改造項目,我們采用此法焊接碰頭口、返修口共28道,焊接一次透視合格率100%),值得我們推廣使用。

上麵四種不鏽鋼打底焊方法各有優缺點,在實際施工中,我們應根據現場的具體條件,既要考慮施工成本的高低,又要考慮焊接質量及施工進度,合理地選擇施工工藝。

 

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