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以304L和316L型奥氏体和2505型双相不锈钢焊接件为对象,采用屏蔽金属弧焊与点焊方式,进行低温示波冲击试验研究,温度范围从室温至-196℃。结果表明,随试验温度的降低,304L与316L型奥氏体不锈钢焊件的冲击能量略有减小,而其相应焊条的冲击能量有很大减小。随着双相不锈钢焊件与焊条从韧性向脆性的转变,其冲击能量减小了至少5%。从试件的断裂面可看出,奥氏体不锈钢焊件与焊条呈现韧性断裂形态,出现宽深式、窄深式、浅式凹陷;而双相不锈钢焊件与焊条呈现脆性断裂形态,出现大、小延展层断面。依据荷载-时间曲线,说明奥氏体与双相不锈钢的韧性与脆性断裂性能。从控制不锈钢低温下变形机理的主要参数:堆垛层错能,应变诱发马氏体相变及铁素体相变这些方面,探讨两种不锈钢性能的差异。
With 304L and 316L austenitic stainless steel and 2505 duplex stainless steel welded parts as the object, shielded metal arc welding and spot welding were used for low temperature oscillometric impact test. The temperature ranged from room temperature to -196 ℃. The results show that with the decrease of test temperature, the impact energy of 304L and 316L austenitic stainless steel welding parts slightly decreases, but the impact energy of the corresponding welding rod is greatly reduced. As the duplex stainless steel weldment and electrode transition from ductile to brittle, the impact energy is reduced by at least 5%. It can be seen from the fracture surface of the specimen that the austenitic stainless steel weldment and the electrode exhibit a ductile fracture morphology, showing a wide deep type, a narrow deep type and a shallow depression; while the duplex stainless steel weldment and the electrode exhibit a brittle fracture appearance Large and small extension of the cross-section. According to the load-time curve, the ductile and brittle fracture properties of austenite and duplex stainless steel are described. From the aspects of controlling the deformation mechanism of stainless steel at low temperature, such as stacking fault stacking, strain-induced martensitic transformation and ferrite transformation, the differences between the two stainless steels were discussed.