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一、前言由于焊接结晶过程的特点,在具有稳定的奥氏体成分的焊缝中会出现δ-Fe。δ-Fe的存在,一方面使焊缝具有较大的破断和开裂抗力;另一方面,若δ-Fe数量过多,在使用过程中,δ-Fe能转化为脆性的σ相,从而使材料产生脆性。因此在设计重要的不锈钢焊件时,往往规定焊缝显微组织中δ-Fe的数量。所以正确测定奥氏体焊缝中δ-Fe的数量,无论在科研方面,还是在生产方面都具有重要的意义。由于焊缝金属的快速冷却,焊缝中δ-Fe的结构非常细小,通常虽内部互相连结的枝晶状形式出现,这给一般的测试方法的采用带来了困难(如金相法)。X射线结构分析
I. Preface Due to the characteristics of the welding crystallization process, δ-Fe appears in the weld with stable austenite composition. δ-Fe, on the one hand to make the weld has greater resistance to rupture and cracking; the other hand, if the amount of δ-Fe is too much, in the course of use, δ-Fe can be transformed into brittle σ phase, so that Material is brittle. Therefore, in the design of important stainless steel welds, the provisions of the weld microstructure of the amount of δ-Fe. Therefore, the correct determination of the amount of δ-Fe in the austenitic weld is of great significance both in scientific research and in production. Due to the rapid cooling of the weld metal, the structure of δ-Fe in the weld is very small, usually in the form of interdendritic inter-connected dendrites, which poses difficulties for the general test methods (metallography, for example). X-ray structure analysis