Accelerated corrosion test method of heavy duty coated steel

摘要

PROBLEM TO BE SOLVED: To provide a technology for accurately predicting corrosion in a short period of time considering a corrosion mechanism regarding a double anticorrosive coating steel material.SOLUTION: A method for testing corrosion acceleration of a double anticorrosive coating steel material according to the present invention is a method for testing corrosion acceleration of the material having a coating edge. The method includes: an actual-environment exposure test step for calculating a speed of corrosion of an exposed steel material part a (mm/year) and a speed of rust invasion into a coating layer b (mm/year) by performing an exposure test for a double anticorrosive coating steel test piece under the actual environment; and a preparatory corrosion acceleration test step for calculating a speed of steel material corrosion a'(mm/year) and a speed of rust invasion into the coating layer b' (mm/year) by performing a corrosion acceleration test under plural kinds of test conditions using a test piece of the same specification as that used in the actual-environment exposure test step. The method calculates an expression b'×a/(b×a') regarding the steel material corrosion speed a' (mm/year) and the rust invasion speed b' (mm/year), which are obtained under each test condition performed in the preparatory corrosion acceleration test step, and sets a test condition with the value of the expression being closest to "1" in the condition of the corrosion acceleration test. Further, the corrosion acceleration test is carried out using the set test condition.