Determination of critical pitting temperatures by calcium chloride test, results of round-robin test

摘要

At the Institute for Corrosion Protection (Institut fur Korrosionsschutz) in Dresden, the CaCl{sub}2 test was developed to test high-alloyed CrNiMo steels and NiCrMo alloys and was applied for pitting and crevice corrosion resistance tests of those materials and their weldments. This test was carried out as a potentiostatic test at 0.2V{sub}(SCE) in a solution of 4.5 mol/l CaCl{sub}2 with an initial pH value of 3.2. Investigations on the influence of filler material, heat treatment and varying heat inputs per unit length of the welds confirm the applicability of the test. With reference to the results from a round-robin test carried out by a study group of the GfKORR working committee Corrosion Protection of Iron and Steel (Korrosionsschutz von Eisen und Stahl) on material grade 2.4605 (alloy 59) and its weldments, the study group concludes that, in research projects, the CaCl{sub}2 test is a good test to characterise the localised corrosion behaviour of welded joints of high-alloyed CrNiMo steels and NiCrMo alloys. However, to use it as quality assurance test would be too complex and susceptible to individual measuring differences.