The ballistic and the magnetic pendulum methods were used to determine corrosion rates of ferromagnetic strands hung at seacoasts, spas, and a factory district and those immersed in acids at our laboratory. The results obtained magnetically agreed with the ones obtained by measuring cross-sectional area and weight losses of the wire, and the same precision of ±0.5% was shown, although accurate rates were rejected so long as zinc protecting layer remained on the surface.
Correlations between corrosion rates and breaking tensile loads were investigated and linear relations were obtained within the test range of corrosion rates up to 50%.
No change in the qualities of the steel parts exempted from corrosion was detected by measurements of their hardness and magnetic σ, and effects of some magnetic corrosion products, such as γ-Fe₂O₃, on the experimental results were minimized below 1% even in the case of 40% corrosion.

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For the purpose of finding the most suitable laboratory corrosion test to estimate the corrosion resistance of 18 Cr stainless steel (SUS 24) strips under atmospheric circumstances, field test and laboratory tests, i. e. salt spray test, humidity test, dew-cycle corrosion test, thermographic corrosion test, and boiling nitric acid test (6hrs and 48hrs) were applied to 12 kinds of 18 Cr stainless steel strips. But the results of all the laboratory tests didn't coincide with the one of the field test. There were, however, a few kinds of strips that showed comparatively good (No. 2) or poor (No. 1) performance through all the tests.

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