The development of modern stainless steel technology, has begun to use complex phase austenitic - ferritic stainless steel 20Cr-8Ni-3.5Mo to cast a large propeller on the ocean wheel (weighing 3000kg).
Ships often working in ports are particularly vulnerable to sailing logs or other buoys to accelerate the thrusters. Therefore, the use of austenitic stainless steel propulsion can be repaired by straightening or welding method, which is the material on the last issue to be valued.
Pump has long been observed in centrifugal pumps in seawater conditions, such as the use of stainless steel components, you can show a certain degree of reliability. In keeping with the flow of water, using CF-8M cast stainless steel impeller (its composition is equivalent to 316 stainless steel) and 316 stainless steel as the spindle, without any problems.
When the pump stops working, crevice corrosion and pitting corrosion are likely to become serious problems. However, if a relatively thick-walled pump box is to be made from the more lively and rust-prone cast iron, the cast iron will provide cathodic protection during downtime.
When the pump is working, the cathodic protection of the cast iron box will certainly make the rust steel polarization, but the flowing water treats the cathodic protection. In addition, long-term use of pumps may be protective due to the alternating use of both seawater and fresh water.