온실 환경 하에서 20년 경과된 농업용 강관의 부식 및 강도변화

In order to increase the durability of the pipe framed greenhouse, galvanized steel pipes with four corrosion protection treatments were installed in the greenhouse. After 20 years, experiments on surface corrosion and strength change were conducted. Control (untreated) pipes exposed in the atmosphere showed a 1.3% reduction in strength, but little difference from other treatments. The strength of heavy protective coating pipes buried in the ground decreased by 0.6%, showing little change, but untreated pipes decreased by 15.7%. And antirust paint and asphalt coating pipes decreased by 4.2~4.4%. Pipes exposed in the atmosphere did not show severe corrosion in all samples. There was no change in heavy protective coating pipes, and no rust was found in antirust painting pipes either and there was only slight discoloration. Asphalt coating pipes discolored black and some rust was found, and untreated pipes were rusted by 20~30% of the surface. However, untreated pipes buried in the ground were completely rusted, and asphalt coating pipes were rusted by 80~90% of the surface. Antirust painting pipes were rusted by 20~30%, and heavy protective coating pipes did not change almost. The heavy protective coating treatment showed a clear corrosion protection effect even in the parts buried in the ground, and the antirust painting treatment also showed some corrosion protection effect. Therefore, it is judged to be applicable to the field of pipe framed greenhouses.