Using Meteorological Data to Evaluate Atmospheric Corrosivity for Stainless Steels

摘要

The Makuhari-Messe Convention Center is located in a coastal area, 500 m from the sea, in Chiba city, Chiba prefecture (Honshu). Its roof and eaves are made of 22Cr-0.8Mo stainless steel. To evaluate the corrosivity of the atmosphere beneath the eaves, atmospheric corrosion monitor (ACM) sensors and 22Cr-0.8Mo steel specimens were exposed at five points on the building: sites 1 and 2 were on its southwestern side (side A), facing toward the sea, and sites 3, 4 and 5 were on the northeastern side (side B), facing away from the sea. The sensors were installed in November 1994 and renewed every 1-4 months until November 1996. Sensor output was measured every 10 minutes, together with temperature and relative humidity (RH). The amount of deposited seasalt (W_s) was also measured, based on sensor output combined with RH data. The 22Cr-0.8Mo steel specimens only rusted at sites 1 and 2, and then only during a single exposure period, from April 19, 1995 to June 22, 1995, when W_s increased to more than 1 g/m~2. The exact day when W_s exceeded 1 g/cm~2 and the steel rusted was identified based on the effective coefficient of daily wind-force energy (#alpha#_D~*).