METHOD FOR TESTING CORROSION ACCELERATION OF HEAVY CORROSION PROTECTION COATED STEEL MATERIAL

PROBLEM TO BE SOLVED: To provide a technology for accurately predicting corrosion in a short period of time considering a corrosion mechanism regarding a heavy corrosion protection coated steel material.SOLUTION: A method for testing corrosion acceleration of a heavy corrosion protection coated steel material comprises: an actual-environment exposure test step for determining a corrosion speed a (mm/y) of an exposed steel material part, a rust penetration speed b (mm/y) under a coated layer and the time period c (y) until the start of the rust penetration under the coated layer; and a preliminary corrosion acceleration test step for determining a steel material corrosion speed a' (mm/y), a rust penetration speed b' (mm/y) under the coated layer and the time period c (y) until the start of the rust penetration under the coated layer by performing corrosion acceleration tests, under a plurality of types of test conditions using a test specimen of the same specification as that used in the actual-environment exposure test step. The steel material corrosion speed a' (mm/y), the rust penetration speed b' (mm/y) and the time period c (y) under each condition obtained in the preliminary corrosion acceleration test step satisfy the following formula (1) and (2): 0.7≤b'×a/(b×a')≤1.3 ...(1); 0.4≤c×a/(c'×a') ...(2).