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高压列管氨冷凝器是年产3000吨合成氨厂中高压设备之一。氨冷凝器在应山和远安化肥厂使用时发生爆破事故。为了查明发生爆破的原因,将应山化肥厂已爆破的那台氨冷凝器进行解剖,作原材料的常规性能试验、爆破断口的金相、粗相、电镜等试验研究。对结构应力进行了分析计算,对各化肥厂的工艺流程变化和在用的同类型产品的使用情况作了了解,并将部分氨冷凝器的环焊缝进行了检查。为了估算在用氨冷凝器的残余寿命,又解剖了两台产品,做焊接接头的性能试验,测定焊缝和熔合区的裂纹扩展门槛值△K_(th),焊接接头的断裂韧性δ_c,裂纹扩展速率da/dN。测定了材料脆性转变温度。根据所测得的数据和分析计算的应力水平,在正常操作状态下,假定焊缝中存在一定尺寸的缺陷,通过计算得出临界裂纹尺寸和疲劳寿命N_f设计曲线。作为氧冷器能否继续使用的参考意见,最后谈了几点看法,
High-pressure tube ammonia condenser is an annual output of 3,000 tons of ammonia plant in the high-pressure equipment. Ammonia condensers exploded in Yingshan and Yuan’an Chemical Fertilizer Plant. In order to identify the cause of the blasting, the ammonia condenser that had been demolished at Yingshan Fertilizer Factory was dissected to conduct the conventional performance test of raw materials, the metallographic, coarse phase and electron microscope test of blasting fracture. The structural stress was analyzed and calculated, and the process flow changes of various fertilizer plants and the use of the same type of products were also understood. The girth weld of some ammonia condensers was also inspected. In order to estimate the residual life of the ammonia condenser, two products were dissected to make the performance test of the welded joint. The crack propagation threshold △ K th, the fracture toughness δ_c of the welded joint and the crack Expansion rate da / dN. The brittle transition temperature was measured. According to the measured data and analysis of the calculated stress level, under normal operating conditions, the existence of a certain size defects in the weld, calculated by the critical crack size and fatigue life N_f design curve. As an oxygen cooler can continue to use the reference opinion, finally talked about the views,