Efficiency of some stress-corrosion inhibitors

1. A study of the time-to-rupture of grade 30 Kh steel tested in 6 N H₂SO₄ solution at a stress of 120 kgf/mm² in the presence of various stress-corrosion inhibitors has shown that KPI-1 is the most effective inhibitor, its addition bringing about a 340-fold increase in time-to-rupture. 2. The stress dependence of time-to-rupture of 30 Kh steel in a 6 N H₂SO₄ solution containing 3g/l KPI-1 has been determined, and it has been shown that KPI-1 retains its stress-corrosion inhibiting power within a wide range of applied stress (60-120 kgf/mm²) and exposure time (up to 10⁴min). 3. The increased effectiveness of KPI-1 in the low stress range is attributable to an increase in the degree of adsorption indicated by a slight shift in the electrode potential of the steel specimens toward more electropositive values.