1.4776 | GX40CrSi28 Failed welding for fabricating purposes

The company CASTService GmbH from Herzogenrath commissioned us to investigate the cause of cracked grate bars of a pusher grate of an incineration plant. The heat-resistant grate bars made of ferritic chromium steel failed prematurely after approx. 6 months of use. The entire cross-section is affected by shrinkage cavities and hot cracks. The “cosmetic top layers” concealed the full extent of the defects. The production or repair welds were superficially abraded and could not be detected by a visual testing in the delivery status. Only after a certain time of operation and slightly different oxidation behavior of the filler metal did these become visible under oblique illumination. With the knowledge gained, CASTService was able to initiate appropriate remedial measures in the foundry and supply replacements at short notice.