Cases of Corrosion in Tap Water and Hot Water Supply Facilities of Stainless Steel Type 304 Pipes and Fundamental Study on Their Corrosion Resistance

Abstract

We used case study analyses and corrosion tests to assess the corrosion resistance of stainless steel type 304 pipes in tap water and hot water facilities. Circulating test equipment used for corrosion tests and two types of samples, plates, and straight pipe specimens were examined in changing conditions of residual chlorine concentration in the test water. Case study analysis results demonstrated that high degrees of pitting corrosion occurred on straight pipes with inner diameter of less than 50 mm. Results of corrosion tests show that the residual chlorine concentration around the pitting corrosion of stainless steel type 304 was greater than 0.5 mg/L in the plate, irrespective of the residual chlorine concentration in the straight pipe specimens. Results suggest that straight pipes have higher corrosion susceptibility because of bending during production.