高温下焊接试样的力学行为及其与实际焊接构件之间的关系

Mechanical Behavior of Laboratory Cross-Weld Specimen and its Relation with Practical Cases at Elevated Temperature

关键词:  高温  焊接  试验方法  尺寸效应  本构关系  多轴应力  寿命评价

Key words:  high temperature  weld  experimental method  size effect  constitutive equation  multi-axial stress  life assessment

摘要:

焊接构件的高温强度的可靠设计对保证高温压力容器及管道的结构完整性具有十分重要的意义。由于焊材或母材的性质均很难反映焊接接头的整体强度,用焊缝试样进行试验提供了合理评价焊接接头工艺性能的可能。但是试验室的焊缝试样能否真实地反映焊接构件的力学行为,则仍是需要进一步研究的问题。本文根据实验室单轴试验和计算模拟,揭示了单轴焊缝试样的局限性:用于高温强度评价基本上是合适的,但用于模拟实际焊接构件的力学行为则误差甚大,这取决于焊缝的受力状况。

Abstract:

The reliable design of high temperature strength of welded components is of significant importance in assuring the structural integrity of pressure vessels and pip at elevated temperature. As the performance of weld material or parent material per se could hardly reflect the integral strength of a weldment, the uniaxial cross-weld specimen provides an alternate to qualify the welding procedures. However, a further investigation is still needed in order to interpret the test results of cross-weld specimens for application in practical welded components. In light of the uniaxial material tests and numerical simulations, the present paper reveals that the cross-weld specimen may be used for the high temperature strength assessment, but can hardly be used for simulation of the practical welded component, depending on the loading case of the component.