管线钢及其焊接接头示波冲击试验中Ei和Ep的关系

THE RELATION BETWEEN Ei AND Ep GIVEN BY INSTRUMENTED IMPACT TESTER OF A PIPELINE STEEL AND ITS WELDED JOINT

关键词:  低合金钢  焊接接头  韧性

Key words:  Low alloy steel  Welded joint  Toughness

摘要:

本文通过WX52管线钢及其焊接接头的Charpy V型缺口(CVN)试样和预制疲劳裂纹的Charpy V型缺口(PCVN)试样的示波冲击试验,讨论了区分E_i和E_p的意义及其与E_t的关系(E_i和E_p分别为载荷-挠度曲线上最大载荷前后的能量,E_t为总冲击能量,E_t=E_i+E_p),并研究了应力集中以及试验温度等因素对E_i/E_t及E_p/E_t值的影响。结果表明,在本试验条件下,E_p与E_t成线性关系,这一关系式对材料的显微组织、材料的状态(轧制态或铸态)以及材料的断裂模型不敏感。当缺口前端应力集中程度增大时,E_i/E_t值减小而E_p/E_t值增大;在E_i/E_t-T℃曲线上T_d温度(高于该温度,缺口延性起裂)时,F_i/E_t有一峰值,而E_p/E_t为谷值。

Abstract:

Instrumented impact tests were carried out on a WX52 steel and its welded joint by using Charpy V-notch(CVN)specimens and precracked Charpy V-notch (PCVN) sppecimens.Significance of dividing E_t into E_f and E_p(E_f-pre-maximumload energy in the load-deflection curve,E_p-post-maximum load energy in the load-deflection curve,E_t=E_t+E_p) was discussed.Straight line relation between E_p and E_t was concluded under test condition.The relation was insensitive to microstructure,material state,such as rolling or casting and fracture mode over a certain range of material strength.The E_f/E_t value decreased with increasing strain concentration at the same time as the E_p/E_t value increased.A peak of the E_f/E_t values appeared at the T_d temperature in the E_t-T℃ relation curve,whilst,on the other hand,a valley point of the E_p/E_t values then occurred.