This F.I.P. report on the hydrogen embrittlement test in a solution of ammonium thiocyanate may be considered one of the most important reports of the Commission on Prestressing Steels & Systems.

It is the result of activity over a period of more than 20 years. This activity included collecting reports on damage, analysing them to identify probable causes, developing a test method, conducting research, performing laboratory testing and counter-testing, discussing test results, and accumulating practical experience.

In the early stages of the work, Mme. Brachet from France, who chaired the ad hoc committee responsible for this task, played a major role. However, not only she but all members of the committee carried out excellent work. In later stages, the late Dr. Kubik from Austria took over the leading role. As a manufacturer of prestressing steel, he was firmly convinced of the necessity of developing a reproducible and selective test method indicating susceptibility to stress corrosion. After his much-lamented passing, his successor, Mr. Hampejs, took over the task of compiling all available data and writing this report. It is the unanimous wish of the Commission that this report should be dedicated to the memory of Dr. Kubik.

The report clearly shows the influence of many test parameters on the actual results. It demonstrates that not the stress level, but the strength of the test specimen is the governing parameter for the duration of the test. From this, it can obviously be concluded that the strength of the material is also of major importance in its susceptibility to stress corrosion.

Therefore, this report must not be considered important for metallurgists only. On the contrary, it should be on the desk of the designer, and even more importantly, its contents should be carefully studied by the drafters of standards and directives and incorporated into their documents.

Finally, I would like to thank Mr. Hampejs for the excellent work he has done, and to congratulate him on it.

Prof. Ir. A. S. G. Bruggeling