the role of molybdenum in high chromium cast iron

The molybdenum can increase the intra-molybdenum when the γ-FE is changed to the γ-FE, and the transition is reduced during the transition, so that the transformation is long, reducing the critical cooled rate of the austenite, so that the matrix tissue is quenched perceive improvement.

In the case where the amount of carbon is the same, the alloy element (dense cobalt and aluminum) will generally be reduced by MS. However, high chromium cast iron molybdenum can effectively increase the MS temperature, reduce the amount of residual Aoplasia in room temperature tissue. This is because the molybdenum can significantly reduce the amount of gamma-Fe in γ-Fe, the carbon content reduction is much more affected by MS, and the molybdenum can effectively increase the MS temperature, so it is considered that molybdenum is effective. Improve high chromium cast iron sclerosis element. The slow thick-walled high chromium wear-cast iron parts, 1% -2% of molybdenum can cause sufficient martensite tissue after quenching, resulting in higher quenching hardness.

Molybdenum is mainly present in three ways in high chromium cast iron:

1.A molybdenum carbon compound is formed with carbon. The molybdenum of the addition of high chromium cast iron is consumed to be directly formed with MO2C-based carbide directly formed with carbon. MO2C is a main carbon-molybdenum compound in high chromium cast iron. This carbide has a higher hardness than CR7C3. The MO2C is in a small dot, and it exists with an alpha + MO2C eutectic form. Among chromium-containing iron, molybdenum is also formed (Mo, Fe) 23 C6, and a portion of the carbon atom in the iron solution is immobilized in the compound. The carbide of molybdenum can effectively resist the hard phase of various abrasive erosion, and their presence is advantageous to improve the wear resistance of high chromium cast iron.

2.Soluent into chromium carbonates. Chromous compound containing molybdenum high chromium cast iron contains some molybdenum elements. The molybdenum dissolved into the carbide makes the hardness and strength of (Fe, Cr) 7C3 are improved, and the material abrasion performance is improved accordingly.

3.Solid dissolved in austenite and its transformation product. Molybdenum is soluble in austenite and its transformation product. Molybdenum strongly delay the austenite pearlite transition, so that high chromium cast iron continuously cools the transition curve to the right, effectively improve the hardenability of the matrix metal.

The amount of molybdenum in high chromium cast iron should generally be determined according to the thickness of chromium, chromium carbon ratio and high chromium cast iron parts. If the amount of carbon is high, the casting is thick, the casting is slow, and more molybdenum should be added.

Anyang Huatuo Metallurgy has in the raw materials for steelmaking and casting for more than 20 years, nowadays stock for some FeMo/FerroMoly, if any interests welcome for consult.