Neutron imaging of steel weldments using a B-alloyed filler material

DI LUOZZO N.; SCHULZ M.; FONTANA M.

Garching

Conferencia; Joint Annual Report 2020 of the MLZ and FRM II; 2021

Heinz Maier-Leibnitz Zentrum (MLZ)

Transient liquid phase bonding (TLPB) is a diffusion welding technique enabling a weldment with mechanical properties comparable to the base metal. Seamless carbon steel tubes (Fe-0.12C-1.09Mn, wt.%) were welded by TLPB, using Fe-based B-alloyed foils (Fe-5Si-3B, wt.%) as filler material. Neutron radiography (NR) and tomography (NT) were performed on a sample cut from the joint of the welded tubes on ANTARES.By means of NR and the proposed calibration method, a quantitative B concentration profile was measured across the joint in the region where the TLPB process was completed. In this region, B concentration did not exceed 50 ppm, which explains why the joint is boride-free.In regions where the TLPB process was not finished, borides were found at the joint. NT allowed a three-dimensional visualisation of the size and shape of borides, highlighting its potential as a non-destructive testing technique of TLPB weldments.