Abstract

Neutron diffraction has been used to investigate the stress field in two different welds developed for nuclear applications, namely those obtained by tungsten inert gas welding of P91 martensitic steel (Cr 9, Mn 6, Mo 1, C 0.1, and Fe bal wt %) and hybrid (laser beam and gas metal arc) welding of AISI316LN austenitic steel (17.8 Cr, 12.3 Ni, 1.7 Mn, 2.4 Mo, 0.3 Si, and Fe bal wt %). The sizes of the investigated samples were 100 × 50 × 12 mm for the P91 weld and 220 × 160 × 15 mm for the 316LN weld; unstrained references were prepared for both welds. The neutron diffraction measurements have been carried out utilizing the E3 diffractometer at the BER II reactor in Berlin, with a gauge volume of 2 × 2 × 2 mm³. Lines perpendicular to the weld direction were scanned at different depths inside the material and at different distances from the weld centerline, including the heat affected zone and the weld centerline. Strain and stress values were determined in the three principal directions. In the TIG P91 weld, the stresses are almost completely relieved after a post weld heat treatment for 2 h at 760°C. In the laser beam and gas metal arc 316LN weld not submitted to post weld heat treatment, nearly balancing longitudinal and transverse stress components as high as 300–350 MPa are found within a range of approximately 3 mm around the centerline of weld.

中文翻译：

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第四代核应用的P91马氏体钢和AISI 316LN钢焊缝中的应力分布

摘要

中子衍射已用于研究为核应用开发的两种不同焊缝的应力场，即通过P91马氏体钢（Cr 9，Mn 6，Mo 1，C 0.1和Fe bal wt％）的钨极惰性气体保护焊获得的应力场。以及AISI316LN奥氏体钢（17.8 Cr，12.3 Ni，1.7 Mn，2.4 Mo，0.3 Si和Fe bal wt％）的混合（激光束和气体金属电弧）焊接。P91焊缝的尺寸为100×50×12 mm，316LN焊缝的尺寸为220×160×15 mm。为两种焊缝准备了未拉伸的参考。中子衍射测量是使用E3衍射仪在柏林BER II反应堆中进行的，测量体积为2×2×2 mm ³。在材料内部的不同深度和距焊接中心线（包括热影响区和焊接中心线）的不同距离处扫描垂直于焊接方向的线。沿三个主要方向确定了应变和应力值。在TIG P91焊缝中，在760°C下进行2 h焊后热处理后，应力几乎完全消除。在未进行焊后热处理的激光束和气体金属电弧316LN焊缝中，在围绕焊缝中心线约3 mm的范围内，发现几乎平衡的纵向和横向应力分量高达300-350 MPa。