Corrosion Resistance of Martensitic Chromium Stainless Steel 9Cr18, 9Cr18Mo, 9Cr18MoV

Corrosion Resistance of Martensitic Chromium-Stainless Steels 9Cr18, 9Cr18Mo, 9Cr18MoV

Martensitic chromium stainless steels refer to the martensitic chromium stainless steel series of common chromium stainless steel alloys. These steels include 9Cr18, 9Cr18Mo, and 9Cr18MoV. These chromium stainless steels have excellent corrosion resistance, particularly in non-oxidizing solutions and low concentrations of oxidizing acids and alkalis.

The corrosion resistance of martensitic chromium stainless steel is due to its chromium content, which is generally 18%. Chromium not only has outstanding corrosion resistance and good oxidation resistance, but also has good wear resistance and high strength. Therefore, martensitic chromium stainless steels with a chromium content of 18% or higher are widely used for various industrial applications due to the combined properties of chromium alloying.

The 9Cr18, 9Cr18Mo and 9Cr18MoV are similar, but there are some differences between them. 9Cr18 is a conventional martensitic chromium stainless steel containing 18% chromium and no molybdenum or vanadium. The 9Cr18Mo is a molybdenum containing martensitic stainless steel, with a chromium content of 18%, and the 9Cr18MoV is a vanadium containing martensitic stainless steel with a chromium content of 18%.

9Cr18 has a high hardness of more than HRC55 after heat treatment and is one of the most widely used martensitic stainless steels. It has good high temperature strength and creep strength, good wear resistance and corrosion resistance, but its corrosion resistance is somewhat worse than 9Cr18Mo and 9Cr18MoV. However, the weldability of 9Cr18 is better than that of 9Cr18Mo and 9Cr18MoV.

The corrosion resistance of 9Cr18Mo and 9Cr18MoV is significantly higher than 9Cr18 due to the addition of molybdenum and vanadium elements. 9Cr18Mo is a martensitic chromium stainless steel containing 18% chromium and 2.5-3.5% molybdenum, while 9Cr18MoV contains 18% chromium and 0.8-1.2% vanadium. The content of molybdenum or vanadium in the alloy can enhance the corrosion resistance of the alloy in some media. Such as the addition of molybdenum and vanadium can significantly enhance the corrosion resistance of 9Cr18 stainless steel in chloride media.

In addition, molybdenum and vanadium can refine the grain of 9Cr18 stainless steel after heat treatment and can greatly improve the corrosion resistance of 9Cr18 stainless steel. When the content of molybdenum and vanadium is very small in the 9Cr18 stainless steel, the corrosion resistance of the stainless steel does not change much, but when the content of molybdenum and vanadium is increased, the corrosion resistance of the stainless steel increases significantly.

From this we can conclude that the corrosion resistance of 9Cr18Mo and 9Cr18MoV is higher than that of 9Cr18, mainly due to the content of molybdenum or vanadium in the alloys. The content of molybdenum and vanadium in the alloy can enhance the corrosion resistance of the alloy in some media, and can also improve the grain refinement of the alloy after heat treatment, resulting in an improved corrosion resistance of the alloy.

Martensitic chrome steel9Cr18, 9Cr18Mo and 9Cr18MoV have good corrosion resistance, wear resistance and high strength properties. Moreover, they are widely used in many industries.

9Cr18 is a low carbon martensitic stainless steel with a small amount of chromium. It has excellent corrosion resistance in neutral and alkaline aqueous solutions. But it is susceptible to pitting corrosion in acidic environments. This material is usually used in manufacturing parts of food processing machinery and medical instruments.

9Cr18Mo is a widely used martensitic chromium steel alloyed with molybdenum, thus it has a higher corrosion resistance than 9Cr18. It is widely used in making high accuracy components for medical measurement instruments, kitchen tableware, jet bomb nozzles, etc.

9Cr18MoV is a high alloy corrosion resistant chromium stainless steel, which contains 0.4% molybdenum and 0.4% vanadium. Its corrosion resistance comparable to that of 9Cr18Mo, but it has better wear resistance, which makes it more suitable for tools and uses that need higher wear resistance.

In summary, 9Cr18, 9Cr18Mo and 9Cr18MoV have good corrosion resistance in different environments. 9Cr18 is suitable for neutral and alkaline environments, while 9Cr18Mo and 9Cr18MoV are better in acidic environment. The wear resistance of 9Cr18MoV is better than that of 9Cr18 and 9Cr18Mo, So it is more suitable for using in wear resistant tools.