Thread-forming screws, manufactured from martensitic and austenitic stainless steels, were tested concerning their susceptibility with relation to stress corrosion cracking. Based as closely on application usage as possible, testing comprised using the fasteners to clamp steel sheets of different material types at changing corrosion conditions according to DIN 50021-SS and DIN 50018-KWF 2,OS.
During the exposure until 90% of the martensitic drilling screws had failed due to hydrogen-induced stress corrosion cracking. Such fasteners represent a safety risk in building practice, even if corrosion resistance requirements are minimal.
The screws made of austenitic materials bore the identical test conditions without cracking.