抄録
Practical knowledge has been gained of the process of an unpainted low-alloy weathering steel to form protective rust films and criteria for its safe architectural applications have been discussed. Model structures made of an unpainted weathering steel containing various structural elements as well as small test pieces placed on the model structure or on the standard exposure racks were examined in terms of the color, texture and weight loss. Among the variables tested, the effects of shelter from rain and run-off were most significant. Such effects were greater in a more polluted atmosphere and in some extreme cases, the surface did not display an optimum and uniform appearance in the maximum test period of four years. Areas under favorable conditions such as horizontal or inclined roofs gave the best results similar to the skyward surface of a test piece on the standard exposure rack.
