论文部分内容阅读
15CrMoR钢是一种珠光体组织的耐热钢,虽然焊接性与低合金结构钢相似,但由于钢中加说入了Cr、Mo、V、W、Nb、Ti等合金元素,使碳当量增加,从而增大了钢的淬硬倾向,容易产生冷裂纹。我厂在焊接重油加氢高压空冷器管束中集箱时,由于所用母材与焊缝金属中碳及合金元素含量差异较大,在焊接过程中,当滞后相变的母材热影响区发生奥氏体向马氏体转变时,氢会以过饱和状态残存于马氏体中,易产生氢致裂纹,当焊缝冷却后转变为马氏体组织时,还会导致焊缝冷裂纹。由于我厂生产受各方面条件所限,不能—一满足耐热钢焊接所需的条件,故针对我厂产品重油加氢高压空冷器管束中集箱的具体要求和我厂现有条件做以下工艺评定,并达到了满意的效果。
15CrMoR steel is a pearlite heat-resistant steel, although the weldability and low-alloy structural steel similar, but added to the steel plus Cr, Mo, V, W, Nb, Ti and other alloying elements, so that carbon equivalent , Thus increasing the hardenability of steel, prone to cold cracking. I plant in the welding of heavy oil hydrogenation of high pressure air coolers tube header, due to the use of base metal and weld metal in the carbon and alloy elements in large differences in the welding process, when the hysteresis phase transformation of the base material heat-affected zone occurred When austenite is transformed into martensite, hydrogen will remain in the martensite in the supersaturated state, and hydrogen-induced cracking easily occurs. When the weld cools and then changes to martensite, it also causes cold cracks in the weld. As I plant production conditions subject to all aspects, can not - a heat-resistant steel to meet the welding conditions required, so I plant heavy oil hydrogenation of high pressure air coiler tube bundle of the specific requirements and I plant the existing conditions to do the following Process evaluation, and achieved satisfactory results.