双相不锈钢焊接的细则

摘要：<span style="font-family:宋體(tǐ);font-size:small;"> </span> <p style="margin:0cm 0cm 0pt;"> <span style="font-family:宋體(tǐ);mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;"><span style="font-size:small;">双相不锈钢焊接的细则</span></span> </p> <span style="font-family:宋體(tǐ);font-size:small;"> </span> <p style="margin:0cm 0cm 0pt;"> <span style="font-family:宋體(tǐ);mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;"><span style="font-size:small;">奥氏體(tǐ)不锈钢的焊接问题常常与焊缝金属本身有(yǒu)关，尤其是在全奥氏體(tǐ)或奥氏體(tǐ)占优势的焊缝凝固过程中产生的热裂纹倾向。对于一般奥氏體(tǐ)不锈钢，调整填充金属的成分(fēn)，使之具有(yǒu)一定的铁素體(tǐ)含量，</span></span> </p> <span style="font-family:宋體(tǐ);font-size:small;"> </span> <p style="margin:0cm 0cm 0pt;"> <a name="一、通用(yòng)焊接准则"></a><span style="font-family:宋體(tǐ);mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;"><span style="font-size:small;">一、通用(yòng)焊接准则</span></span> </p> <span style="font-family:宋體(tǐ);font-size:small;"> </span> <p style="margin:0cm 0cm 0pt;"> <span style="font-family:宋體(tǐ);mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;"><span style="font-size:small;">双相不锈钢和奥氏體(tǐ)不锈钢的區(qū)别</span></span> </p> <span style="font-family:宋體(tǐ);font-size:small;"> </span> <p style="margin:0cm 0cm 0pt;"> <span style="font-family:宋體(tǐ);mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;"><span style="font-size:small;">奥氏體(tǐ)不锈钢的焊接问题常常与焊缝金属本身有(yǒu)关，尤其是在全奥氏體(tǐ)或奥氏體(tǐ)占优势的焊缝凝固过程中产生的热裂纹倾向。对于一般奥氏體(tǐ)不锈钢，调整填充金属的成分(fēn)，使之具有(yǒu)一定的铁素體(tǐ)含量，可(kě)将这些问题减至低程度。高合金奥氏體(tǐ)不锈</span></span><span style="font-family:'Times New Roman';font-size:small;"> </span><span style="font-family:宋體(tǐ);mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;"><span style="font-size:small;">钢需要使用(yòng)镍基填充金属，奥氏體(tǐ)凝固不可(kě)避免，需要通过降低热输入、多(duō)道焊来控制。</span></span> </p> <span style="font-family:宋體(tǐ);font-size:small;"> </span> <p style="margin:0cm 0cm 0pt;"> <span style="font-family:宋體(tǐ);mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;"><span style="font-size:small;">由于双相不锈钢铁素體(tǐ)含量高，</span></span><span style="font-family:'Times New Roman';font-size:small;"> </span><span style="font-size:small;"><span style="font-family:宋體(tǐ);mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">具有(yǒu)非常好的抗热裂性，焊接时很(hěn)少考虑热裂。双相不锈钢焊接主要的问题与热影响區(qū)有(yǒu)关，而不是焊缝金属。热影响區(qū)的问题是耐蚀性及韧性损失或焊后开裂。為(wèi)了避免发生上述问题，焊接工艺的重点是大程度减少在</span><span style="font-family:'Times New Roman';"><span lang="EN-US">“</span></span><span style="font-family:宋體(tǐ);mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">红热</span><span style="font-family:'Times New Roman';"><span lang="EN-US">” </span></span><span style="font-family:宋體(tǐ);mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">温度范围总的停留时间，而不是控制任何一道焊接的热输入。经验表明，这种方法可(kě)使焊接工艺从技术和经济角度都优化。</span></span> </p> <span style="font-family:宋體(tǐ);font-size:small;"> </span> <p style="margin:0cm 0cm 0pt;"> <span style="font-family:宋體(tǐ);mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;"><span style="font-size:small;">这里将给出双相不锈钢焊接的一些一般准则，以及这些基本知识和准则在具體(tǐ)焊接方法中的应用(yòng)。</span></span> </p> <span style="font-family:宋體(tǐ);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(tǐ);mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">原材料的选择</span></span> </p> <span style="font-family:宋體(tǐ);font-size:small;"> </span> <p style="margin:0cm 0cm 0pt;"> <span style="font-size:small;"><span style="font-family:宋體(tǐ);mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">双相不锈钢对焊接的适应性可(kě)随化學(xué)成分(fēn)和生产工艺的变化而发生显著变化。已反复强调过母材含有(yǒu)足量氮的重要性。如果原材料缓慢地冷却通过</span><span style="font-family:'Times New Roman';"><span lang="EN-US">700 - 1000</span></span><span style="font-family:宋體(tǐ);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"> (1300 - 1800</span></span><span style="font-family:宋體(tǐ);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">) </span></span><span style="font-family:宋體(tǐ);mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">温度區(qū)间，或允许在水淬前空冷通过该區(qū)间一分(fēn)钟左右，那么本应留给焊工</span></span><span style="font-family:'Times New Roman';font-size:small;"> </span><span style="font-size:small;"><span style="font-family:宋體(tǐ);mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">完成焊接而不产生任何有(yǒu)害相析出的时间被耗尽。需要注意的是，实际进行加工制造的材料，其成分(fēn)和生产过程的冶金条件应当与用(yòng)于焊接工艺评定的材料的质量条件相同。此系列文(wén)章的</span><span style="font-family:'Times New Roman';"><span lang="EN-US"> “</span></span><span style="font-family:宋體(tǐ);mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">终端用(yòng)户技术条件和质量控制</span><span style="font-family:'Times New Roman';"><span lang="EN-US">” </span></span><span style="font-family:宋體(tǐ);mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">部分(fēn)给出了根据成分(fēn)和合适试验规范选择原材料的方法。</span></span> </p> <span style="font-family:宋體(tǐ);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(tǐ);mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">焊前清理(lǐ)</span></span> </p> <span style="font-family:宋體(tǐ);font-size:small;"> </span> <p style="margin:0cm 0cm 0pt;"> <span style="font-family:宋體(tǐ);mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;"><span style="font-size:small;">焊前应清理(lǐ)全部加热部位，这一要求不仅适用(yòng)于双相不锈钢，而且适用(yòng)于所有(yǒu)不锈钢。确定母材和填充金属化學(xué)成分(fēn)的前提条件是没有(yǒu)额外的污染源。灰尘、油脂、油污、油漆和任何形式的水分(fēn)都会干扰焊接操作并对焊件的耐蚀性和力學(xué)性能(néng)产生不</span></span><span style="font-family:'Times New Roman';font-size:small;"> </span><span style="font-family:宋體(tǐ);mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;"><span style="font-size:small;">利影响。如果焊前不对材料进行彻底清理(lǐ)，则无论多(duō)少工艺评定均是无效的。</span></span> </p> <span style="font-family:宋體(tǐ);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(tǐ);mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">接头设计</span></span> </p> <span style="font-family:宋體(tǐ);font-size:small;"> </span> <p style="margin:0cm 0cm 0pt;"> <span style="font-family:宋體(tǐ);mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;"><span style="font-size:small;">双相不锈钢的接头设计必须有(yǒu)助于完全焊透并避免在凝固的焊缝金属中存在未熔合的母材。好采用(yòng)机加工而不采用(yòng)砂轮打磨坡口，以便使焊接區(qū)厚度或间隙均匀。必须打磨时，应特别注意坡口加工及其装配的均匀一致。為(wèi)了保证完全熔合和焊透，应当去掉任何打磨毛刺。对于奥氏體(tǐ)不锈钢，有(yǒu)经验的焊工可(kě)通过控制焊炬克服坡口加工的某些缺陷。但对于双相不锈钢，这些技巧会造成材料在有(yǒu)害温度區(qū)间停留时间比预期的时间長(cháng)，导致结果超出合格工艺要求。</span></span> </p> <span style="font-family:宋體(tǐ);font-size:small;"> </span> <p style="margin:0cm 0cm 0pt;"> <span style="font-size:small;"><span style="font-family:宋體(tǐ);mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">双相不锈钢的一些接头设计如图</span><span style="font-family:'Times New Roman';"><span lang="EN-US">18</span></span><span style="font-family:宋體(tǐ);mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">所示。其他(tā)设计如能(néng)保证焊缝完全焊透且烧穿的危低，则它们也是合理(lǐ)的。</span></span> </p> <span style="font-family:宋體(tǐ);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(tǐ);mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">预热</span></span> </p> <span style="font-family:宋體(tǐ);font-size:small;"> </span> <p style="margin:0cm 0cm 0pt;"> <span style="font-size:small;"><span style="font-family:宋體(tǐ);mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">由于预热可(kě)能(néng)是有(yǒu)害的，所以一般不推荐预热。如果没有(yǒu)特殊正当的理(lǐ)由，不应当把预热作為(wèi)一个工序。若用(yòng)于消除天冷或夜间冷凝形成的湿气时，预热可(kě)能(néng)是有(yǒu)益的。当采用(yòng)预热去除湿气时，应将钢均匀地加热到约</span><span style="font-family:'Times New Roman';"><span lang="EN-US">100</span></span><span style="font-family:宋體(tǐ);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"> (200</span></span><span style="font-family:宋體(tǐ);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">) </span></span><span style="font-family:宋體(tǐ);mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">且只能(néng)在坡口清理(lǐ)后进行。</span></span> </p> <span style="font-family:宋體(tǐ);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">5.</span></span><span style="font-family:宋體(tǐ);mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">热输入与层间温度</span></span> </p> <span style="font-family:宋體(tǐ);font-size:small;"> </span> <p style="margin:0cm 0cm 0pt;"> <span style="font-family:宋體(tǐ);mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;"><span style="font-size:small;">双相不锈钢能(néng)够容许相对高的热输入。焊缝金属凝固后的双相组织的抗热裂性大大优于奥氏體(tǐ)焊缝金属。</span></span><span style="font-family:'Times New Roman';font-size:small;"> </span><span style="font-family:宋體(tǐ);mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;"><span style="font-size:small;">双相不锈钢具有(yǒu)较高的导热率和较小(xiǎo)的热膨胀系数，焊缝处没有(yǒu)像奥氏體(tǐ)不锈钢那样高的局部热应力。尽管有(yǒu)必要对焊缝要求提出严格限制，但热裂纹不是个常见的问题。</span></span> </p> <span style="font-family:宋體(tǐ);font-size:small;"> </span> <p style="margin:0cm 0cm 0pt;"> <span style="font-family:宋體(tǐ);mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;"><span style="font-size:small;">极低的热输入可(kě)导致母材熔合區(qū)和热影响區(qū)铁素體(tǐ)含量过高，韧性和耐蚀性降低。极高的热输入增加了形成金属间相的危险。為(wèi)了防止热影响區(qū)的问题，焊接工艺规程应允许该區(qū)域焊后快速冷却。工件温度很(hěn)重要，</span></span><span style="font-family:'Times New Roman';font-size:small;"> </span><span style="font-family:宋體(tǐ);mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;"><span style="font-size:small;">因為(wèi)它对热影响區(qū)的冷却影响大。</span></span><span style="font-family:'Times New Roman';font-size:small;"> </span><span style="font-size:small;"><span style="font-family:宋體(tǐ);mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">作為(wèi)一般准则，经济型和标准双相不锈钢的高层间温度限制在</span><span style="font-family:'Times New Roman';"><span lang="EN-US">150</span></span><span style="font-family:宋體(tǐ);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"> (300</span></span><span style="font-family:宋體(tǐ);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">)</span></span><span style="font-family:宋體(tǐ);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(tǐ);mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">超级双相不锈钢限制在</span><span style="font-family:'Times New Roman';"><span lang="EN-US">100</span></span><span style="font-family:宋體(tǐ);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"> (210</span></span><span style="font-family:宋體(tǐ);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">)</span></span><span style="font-family:宋體(tǐ);mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">。进行焊接工艺评定时应采用(yòng)该限制值，生产性焊接中也应监测以确保层间温度不高于工艺评定时所采用(yòng)的温度。電(diàn)子温度探头和热電(diàn)偶是监控层间温度较好的手段。在焊接工艺评定中，使多(duō)道焊试件的层间温度低于实际制造中能(néng)够经济合理(lǐ)地达到的层间温度，这种做法是不慎重的。进行大量焊接时，规划好焊接工序使各道次间有(yǒu)足够的冷却时间是良好、经济的做法。</span></span> </p> <span style="font-family:宋體(tǐ);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">6.</span></span><span style="font-family:宋體(tǐ);mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">焊后热处理(lǐ)</span></span> </p> <span style="font-family:宋體(tǐ);font-size:small;"> </span> <p style="margin:0cm 0cm 0pt;"> <span style="font-family:宋體(tǐ);mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;"><span style="font-size:small;">双相不锈钢不需要进行焊后应力消除处理(lǐ)，且这样做可(kě)能(néng)是有(yǒu)害的，</span></span><span style="font-family:'Times New Roman';font-size:small;"> </span><span style="font-family:宋體(tǐ);mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;"><span style="font-size:small;">因為(wèi)热处理(lǐ)可(kě)</span></span><span style="font-family:'Times New Roman';font-size:small;"> </span><span style="font-size:small;"><span style="font-family:宋體(tǐ);mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">使金属间相</span><span style="font-family:'Times New Roman';"><span lang="EN-US"> (700 - 1000°C/1300 - 1830°F) </span></span><span style="font-family:宋體(tǐ);mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">或</span><span style="font-family:'Times New Roman';"><span lang="EN-US"> α’ (475</span></span><span style="font-family:宋體(tǐ);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">/ 885</span></span><span style="font-family:宋體(tǐ);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">) </span></span><span style="font-family:宋體(tǐ);mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">脆性相析出，降低韧性和耐蚀性。焊后热处理(lǐ)温度超过</span><span style="font-family:'Times New Roman';"><span lang="EN-US">315</span></span><span style="font-family:宋體(tǐ);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"> (600</span></span><span style="font-family:宋體(tǐ);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">) </span></span><span style="font-family:宋體(tǐ);mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">会导致有(yǒu)害相的析出。</span></span> </p> <span style="font-family:宋體(tǐ);font-size:small;"> </span> <p style="margin:0cm 0cm 0pt;"> <span style="font-size:small;"><span style="font-family:宋體(tǐ);mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">双相不锈钢的焊后热处理(lǐ)应当包括完全固溶退火，然后水淬</span><span style="font-family:'Times New Roman';"><span lang="EN-US"> (</span></span><span style="font-family:宋體(tǐ);mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">见表</span><span style="font-family:'Times New Roman';"><span lang="EN-US"> 11)</span></span><span style="font-family:宋體(tǐ);mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">。自熔焊后应考虑完全固溶退火，</span></span><span style="font-family:'Times New Roman';font-size:small;"> </span><span style="font-family:宋體(tǐ);mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;"><span style="font-size:small;">因為(wèi)如果在焊接过程中没有(yǒu)采用(yòng)过合金化的填充金属，则显微组织中铁素體(tǐ)含量将很(hěn)高。</span></span> </p> <span style="font-family:宋體(tǐ);font-size:small;"> </span> <p style="margin:0cm 0cm 0pt;"> <span style="font-family:宋體(tǐ);mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;"><span style="font-size:small;">如果焊后打算进行完全固溶退火和淬火，例如零部件的制造，则热处理(lǐ)应视為(wèi)焊接工艺的一部分(fēn)。退火处理(lǐ)可(kě)解决铁素體(tǐ)过多(duō)及金属间相相关的问题，制造工艺允许在终退火处理(lǐ)前存在一些不太如意的中间状态。</span></span> </p> <span style="font-family:宋體(tǐ);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">7.</span></span><span style="font-family:宋體(tǐ);mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">理(lǐ)想的相平衡</span></span> </p> <span style="font-family:宋體(tǐ);font-size:small;"> </span> <p style="margin:0cm 0cm 0pt;"> <span style="font-size:small;"><span style="font-family:宋體(tǐ);mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">常常说双相不锈钢的相平衡為(wèi)</span><span style="font-family:'Times New Roman';"><span lang="EN-US"> “50-50”</span></span><span style="font-family:宋體(tǐ);mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">，等量的奥氏體(tǐ)与铁素體(tǐ)。</span></span><span style="font-family:'Times New Roman';font-size:small;"> </span><span style="font-size:small;"><span style="font-family:宋體(tǐ);mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">然而，严格说来这是不正确的，因為(wèi)现代双相不锈钢中铁素體(tǐ)约為(wèi)</span><span style="font-family:'Times New Roman';"><span lang="EN-US">40</span></span><span style="font-family:宋體(tǐ);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"> - 50</span></span><span style="font-family:宋體(tǐ);mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">％，其余為(wèi)奥氏體(tǐ)。通常认為(wèi)，当铁素體(tǐ)含量至少為(wèi)</span><span style="font-family:'Times New Roman';"><span lang="EN-US">25 - 30</span></span><span style="font-family:宋體(tǐ);mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">％、其余為(wèi)奥氏體(tǐ)时，可(kě)以获得双相不锈钢特有(yǒu)的优点。</span></span> </p> <span style="font-family:宋體(tǐ);font-size:small;"> </span> <p style="margin:0cm 0cm 0pt;"> <span style="font-family:宋體(tǐ);mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;"><span style="font-size:small;">在一些焊接方法中，特别是以焊剂保护為(wèi)基础的方法中，相平衡向奥氏體(tǐ)含量较高的方向调整以改善韧性，补偿因焊剂使焊缝氧含量增加引起的韧性损失。这些填充金属的韧性遠(yuǎn)低于钢板或钢管固溶处理(lǐ)后可(kě)能(néng)达到的很(hěn)高的韧性值，但焊缝金属的韧性仍足以满足预期的要求。没有(yǒu)一种焊接方法可(kě)使焊缝金属的韧性与锻轧材完全退火处理(lǐ)后所达到的韧性一样高。如果将焊缝金属的铁素體(tǐ)含量限制在轧钢厂退火处理(lǐ)的双相不锈钢所要求的小(xiǎo)值之上，会对可(kě)用(yòng)的焊接方法形成不必要的限制。</span></span> </p> <span style="font-family:宋體(tǐ);font-size:small;"> </span> <p style="margin:0cm 0cm 0pt;"> <span style="font-family:宋體(tǐ);mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;"><span style="font-size:small;">热影响區(qū)的相平衡，即原始锻轧钢板或钢管加上额外的焊接热循环，其铁素體(tǐ)含量通常略高于原始材料。用(yòng)金相法**测定热影响區(qū)的相平衡几乎是不可(kě)能(néng)的。如果该區(qū)域铁素體(tǐ)含量很(hěn)高，也许说明出现过极快速冷却的异常情况，从而导致铁素體(tǐ)含量过高和韧性降低。</span></span> </p> <span style="font-family:宋體(tǐ);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">8.</span></span><span style="font-family:宋體(tǐ);mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">异种金属的焊接</span></span> </p> <span style="font-family:宋體(tǐ);font-size:small;"> </span> <p style="margin:0cm 0cm 0pt;"> <span style="font-family:宋體(tǐ);mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;"><span style="font-size:small;">双相不锈钢可(kě)与其他(tā)双相不锈钢、奥氏體(tǐ)不锈钢、碳素钢和低合金钢焊接。</span></span> </p> <span style="font-family:宋體(tǐ);font-size:small;"> </span> <p style="margin:0cm 0cm 0pt;"> <span style="font-family:宋體(tǐ);mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;"><span style="font-size:small;">双相不锈钢与其他(tā)双相不锈钢焊接时，通常使用(yòng)镍含量高于母材的双相不锈钢填充金属。提高填充金属的镍含量可(kě)保证焊缝在冷却过程中形成足够的奥氏體(tǐ)。</span></span> </p> <span style="font-family:宋體(tǐ);font-size:small;"> </span> <p style="margin:0cm 0cm 0pt;"> <span style="font-size:small;"><span style="font-family:宋體(tǐ);mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">双相不锈钢与奥氏體(tǐ)不锈钢焊接时，常使用(yòng)低碳和钼含量介于二者之间的奥氏體(tǐ)不锈钢填充金属；通常使用(yòng)</span><span style="font-family:'Times New Roman';"><span lang="EN-US">AWS E 309LMo/ER309LMo</span></span><span style="font-family:宋體(tǐ);mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">。双相不锈钢与碳素钢和低合金钢的焊接一般采用(yòng)上述同样的填充金属或</span><span style="font-family:'Times New Roman';"><span lang="EN-US">AWS E309L/ER309L</span></span><span style="font-family:宋體(tǐ);mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">。如果使用(yòng)镍基填充金属，则它们不应当含有(yǒu)铌。由于奥氏體(tǐ)不锈钢的强度比双相不锈钢低，故使用(yòng)奥氏體(tǐ)不锈钢填充金属的焊接接头不如双相不锈钢母材强度高。</span></span> </p> <span style="font-family:宋體(tǐ);font-size:small;"> </span> <p style="margin:0cm 0cm 0pt;"> <span style="font-size:small;"><span style="font-family:宋體(tǐ);mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">表</span><span style="font-family:'Times New Roman';"><span lang="EN-US">16</span></span><span style="font-family:宋體(tǐ);mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">归纳了双相不锈钢与异种金属焊接时常用(yòng)的填充金属。这些例子给出了</span><span style="font-family:'Times New Roman';"><span lang="EN-US">AWS</span></span><span style="font-family:宋體(tǐ);mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">焊条牌号</span><span style="font-family:'Times New Roman';"><span lang="EN-US"> (E)</span></span><span style="font-family:宋體(tǐ);mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">，但是根据焊接工艺、接头形状和其他(tā)条件的不同，可(kě)考虑采用(yòng)焊丝</span><span style="font-family:'Times New Roman';"><span lang="EN-US"> (AWS</span></span><span style="font-family:宋體(tǐ);mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">牌号</span><span style="font-family:'Times New Roman';"><span lang="EN-US">ER) </span></span><span style="font-family:宋體(tǐ);mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">和药芯焊丝。</span></span> </p> <span style="font-family:宋體(tǐ);font-size:small;"> </span> <p style="margin:0cm 0cm 0pt;"> <span style="font-size:small;"><span style="font-family:宋體(tǐ);mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">表</span><span style="font-family:'Times New Roman';"><span lang="EN-US">16 </span></span><span style="font-family:宋體(tǐ);mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">异种金属焊接用(yòng)焊接材料</span></span> </p> <span style="font-family:宋體(tǐ);font-size:small;"> </span> <p style="margin:0cm 0cm 0pt;"> <a name="二、焊接工艺评定"></a><span style="font-family:宋體(tǐ);mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;"><span style="font-size:small;">二、焊接工艺评定</span></span> </p> <span style="font-family:宋體(tǐ);font-size:small;"> </span> <p style="margin:0cm 0cm 0pt;"> <span style="font-size:small;"><span style="font-family:宋體(tǐ);mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">对于标准奥氏體(tǐ)不锈钢，焊接工艺评定试验是相当简单的，仅进行一定数量的试验以证明材料、焊材和焊接方法是合格的。这些评定试验包括硬度试验和弯曲试验</span><span style="font-family:'Times New Roman';"><span lang="EN-US"> (</span></span><span style="font-family:宋體(tǐ);mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">分(fēn)别检验马氏體(tǐ)和热裂</span><span style="font-family:'Times New Roman';"><span lang="EN-US">)</span></span><span style="font-family:宋體(tǐ);mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">，反映了長(cháng)期使用(yòng)铁素體(tǐ)、马氏體(tǐ)或奥氏體(tǐ)不锈钢时可(kě)能(néng)出现的问题。双相不锈钢满足这些要求没有(yǒu)困难，但是这些试验不可(kě)能(néng)发现双相不锈钢中可(kě)能(néng)出现的金属间相或过量铁素體(tǐ)问题。同时，由于需要限制在热影响區(qū)温度范围内的总时间，双相不锈钢的性能(néng)将对截面厚度和实际焊接操作的细节很(hěn)敏感。因此，必须广义地考虑</span><span style="font-family:'Times New Roman';"><span lang="EN-US"> “</span></span><span style="font-family:宋體(tǐ);mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">评定</span><span style="font-family:'Times New Roman';"><span lang="EN-US">”</span></span><span style="font-family:宋體(tǐ);mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;">，即证明在制过程中将使用(yòng)的焊接工艺不会导致材料的工程特性，特别是韧性和耐蚀性出现不可(kě)接受的损失。</span></span> </p> <span style="font-family:宋體(tǐ);font-size:small;"> </span> <p style="margin:0cm 0cm 0pt;"> <span style="font-family:宋體(tǐ);mso-ascii-font-family:&quot;Times New Roman&quot;;mso-hansi-font-family:&quot;Times New Roman&quot;;"><span style="font-size:small;">对每种厚度和形状的焊接都进行焊接工艺评定是比较保险的做法，因為(wèi)方案上的微小(xiǎo)差别在实际制造结果中差别可(kě)能(néng)很(hěn)大。然而，实际加工的复杂性使得这样的试验成本很(hěn)高。如果每种焊接方法对厚断面进行焊接工艺评定，则可(kě)达到节约的目的。</span></span> </p> <span style="font-family:宋體(tǐ);font-size:small;"> </span> <p style="margin:0cm 0cm 0pt;"> <span lang="EN-US"><span style="font-family:'Times New Roman';font-size:small;">&nbsp;</span></span> </p> <span style="font-family:宋體(tǐ);font-size:small;"> </span>