Here is the situation:
Our customer uses analyte cells for electrocoat paint application. The analyte cells facilitate the transfer of acid through the ion exchange resin of the cell. Inside the cell is a 316L stainless steel anode. In this particular application, the stainless steel of one supplier is corroding, while the stainless steel of a second supplier is not experiencing any corrosion. We have sent samples of both anodes out for a compositional analysis and both meet the compositional requirements of 316L Stainless Steel. The stainless steel that is corroding is manufactured in Korea while the non corroding stainless steel is manufactured in South Africa.
According to our current information, there are minimal differences between the two paint tanks. Both tanks are use the same paint; are run at 27-28 C, the tanks are grounded and have similar rectifiers.
The analyte solution is a dilute acetic acid solution. The pH at the start is around 2.7. During the course of a few weeks the pH rose to about 4 and the analyte solution turned red. The 316L anodes weight about 5kg each. In a sixty day period one of the anodes lost 1.3 kg in weight. The anodes with the corrosion are 316L SS Schedule 10 seamless tubes. The anodes with no corrosion are 316L SS Schedule 10 seamed tubes.
Can anyone give me an indication of what is going on here? Why would one corrode and one anode not corrode.
Our customer uses analyte cells for electrocoat paint application. The analyte cells facilitate the transfer of acid through the ion exchange resin of the cell. Inside the cell is a 316L stainless steel anode. In this particular application, the stainless steel of one supplier is corroding, while the stainless steel of a second supplier is not experiencing any corrosion. We have sent samples of both anodes out for a compositional analysis and both meet the compositional requirements of 316L Stainless Steel. The stainless steel that is corroding is manufactured in Korea while the non corroding stainless steel is manufactured in South Africa.
According to our current information, there are minimal differences between the two paint tanks. Both tanks are use the same paint; are run at 27-28 C, the tanks are grounded and have similar rectifiers.
The analyte solution is a dilute acetic acid solution. The pH at the start is around 2.7. During the course of a few weeks the pH rose to about 4 and the analyte solution turned red. The 316L anodes weight about 5kg each. In a sixty day period one of the anodes lost 1.3 kg in weight. The anodes with the corrosion are 316L SS Schedule 10 seamless tubes. The anodes with no corrosion are 316L SS Schedule 10 seamed tubes.
Can anyone give me an indication of what is going on here? Why would one corrode and one anode not corrode.