The effect of porosity on strain evolution and failure of soldered, small-diameter, thin-walled metallic pipes

DOI: 10.1016/j.jmrt.2022.12.088

Authors: Sophie A. M. Mcnair (University of Bath) , Jiraphant Srisuriyachot (University of Bath) , Samuel Omole (University of Bath) , Thomas Connolley (Diamond Light Source) , Andrew Rhead (University of Bath) , Alexander J. G. Lunt (University of Bath)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Journal Of Materials Research And Technology , VOL 9

State: Published (Approved)
Published: December 2022
Diamond Proposal Number(s): 28603

Abstract: Small-diameter, thin-walled pipes have applications in a wide range of industries including high-energy physics, heat transfer, nuclear, medical and communications. There are no standards that exist for welds less than 0.5 mm in width, and as such it is difficult to determine the likely performance of a thin-walled pipe weld. Porosity is largely inevitable in fusion welded joints and is a determining factor in the performance of a connection. This study focused on characterisation of the evolution of strains in soldered welds less than 0.5 mm in width, by incrementally tensile loading samples and studying them in-situ with Synchrotron X-Ray Computed Tomography and X-Ray Diffraction. Two sample geometries were studied, and porosity defects were present in both, although the levels of porosity size, number and area varied dramatically between the two samples. Lattice strain interpretation showed that crack propagation for such samples is not driven by porosity but that crack evolution occurs at the same location and load levels irrespective of the presence of pores. Residual stresses of up to 0.3% from the fusion welding process were seen in both samples and appear to have a greater impact on locations of failure than porosity. Porosity does cause differences in strains across directions, however high strains alone did not appear to cause premature failure. Hence, efforts to improve weld strength should in future focus more on reducing residual stresses than reducing porosity.

Diamond Keywords: Welding

Subject Areas: Engineering, Materials


Instruments: I12-JEEP: Joint Engineering, Environmental and Processing

Added On: 20/12/2022 21:51

Documents:
1-s2.0-S2238785422019780-main.pdf

Discipline Tags:

Materials Engineering & Processes Materials Science Engineering & Technology

Technical Tags:

Imaging Tomography