Due to their corrosion resistance, impact resistance, and high-temperature resistance, 316L thick-walled stainless steel pipes are commonly used in pharmaceuticals, chemicals, food processing, light industry, chemical machinery, industrial pipelines, and mechanical parts. They are also suitable for the production of exhaust pipes and various basic pipelines. However, corrosion can occur after a period of use. So, what should be done if 316L thick-walled stainless steel pipes corrode?
We know that when thick 316L stainless steel pipes are corroded by thermocouples, the anodizing is destroyed, and the negative electrode is protected. If we try to keep the 316L thick-walled stainless steel pipe as a negative electrode from beginning to end, it will not easily corrode. This anti-corrosion method is called pipeline cathodic protection. This is also a method of protecting against corrosion. 316L thick-walled stainless steel pipes not only use movable metal materials as a protective film but also destroy movable metal materials to protect metal components. Further research can also be conducted to perform anodizing without destroying the anodizing process. Therefore, cathodic protection can be divided into the protective film method and the electrical equipment protection method.
In cathodic protection, a relatively active alloy is used as a protective film, inserted into the surface of the 316L thick-walled stainless steel pipe, or connected to the protective metal material with a transmission line, making the protective film and the protective metal material the two sides of a galvanic cell reaction. Since the protective film of the 316L thick-walled stainless steel pipe is an active metal material, it has an anodic oxidation effect in the cell, and is damaged by corrosion from air oxidation. The protective alloy acts as the negative electrode, and the original small rechargeable battery terminates or weakens at the negative electrode, thus protecting the metal material components. When the protective film of the 316L thick-walled stainless steel pipe is about to rust, it can be replaced with another protective film.
Therefore, this anti-corrosion method is a lost-type automotive protection method, also known as cathodic protection. For example, there are zinc blocks in gas-fired steam boilers, and zinc is often embedded around ship propellers. Zinc is more reactive than iron, so zinc slowly corrodes and protects the heating furnace and aircraft propellers. During electrolysis, the electrode connected to the negative terminal of the switching power supply is not easily damaged. In this electrode, electronic equipment is unnecessary, so the negative-walled 316L thick-walled stainless steel pipe itself cannot lose electronic equipment and becomes a positive ion. In other words, the negative electrode is less prone to damage. Based on this fundamental principle, we can use an external current to connect the 316L thick-walled stainless steel pipe to the negative connection of the switching power supply, and set the positive terminals of the auxiliary power supply and the switching power supply as the anodizing connection, then maintain the negative mechanical equipment. Anodizing can be applied to some wastewater pipes, old train tracks, etc., where corrosion occurs slowly under low conditions. This method is similar to the protective film method.
Post time: Apr-27-2026