What are the commonly used cast iron rolls?

In China's current standards, cast iron rolls are divided into chilled cast iron rolls, infinite chilled cast iron rolls, ductile iron rolls and high chromium cast iron rolls four categories. Because of the composition, inoculation, cooling rate, heat treatment, etc., cast iron has formed a huge system. Various cast iron rolls have different arrangement structures and functions and can be used in different rolling mills.

The residual stress and thermal stress will occur in the preparation process before the production and application of the cast iron roll. The use of further by the effect of a variety of periodic stress, including twists and turns, changes, shear, contact stress and thermal stress, etc.

Cast iron rolls have good chip settlement, excellent cooling and cleanliness, and reduce the appearance of scratches. Select the appropriate grinding wheel type and grinding process parameters to ensure that the roll generalization problems, external vibration lines, transverse thread lines, external scratches, etc. does not occur during the grinding process. About small and medium-sized centrifugal roll, generally choose corundum grinding wheel. According to the small and medium-sized centrifugal roller raw material matching corundum grinding wheel, can reach a higher appearance quality and grinding accuracy. The roller type problem is generally mainly composed of too soft grinding wheel.

(1) Chilled cast iron roll operation layer arrangement for the matrix plus carbon compounds, the heart of the gray iron arrangement. The transition orientation (I. e., the transition layer) is clearly identifiable on the fracture surface. Hard cast iron rolls are known for their wear resistance. According to different grades, the hardness of chilled cast iron roll can reach 55 ~ 85HSD.

(2) the infinite chilled cast iron roll operation layer is arranged as the matrix with carbon compound and fine flake graphite, and the heart is arranged as gray iron. There is a gradual transition (the transition layer is very wide), and there is no clear direction on the fracture. By the appearance, the lower limit of hardness is lower than that of the chilled cast iron roll, but after adding the alloy, the hardness can also reach HSD. Infinite chilled cast iron roll has smooth hardness transition and good thermal crack resistance.

(3) because of the spheroidizing effect of magnesium or rare earth elements on carbon, the arrangement of ductile iron rolls is based on spherical graphite, and there are different numbers of carbon compounds in the operation layer. Ductile iron roll hardness scale is very wide, up to 42 ~ 80HSD. Relying on the alloy elements and heat treatment, the matrix is obtained for the needle like arrangement of the nodular cast iron roll, so that the hardness can reach 55 ~ 80HSD. Can also choose the metal type sand lining method to make semi-chilled ductile iron roll, hardness dropped to 35 ~ 55HSD, to the heart of no significant drop, in order to get used to the needs of the hole L ~ roll.

(4) high chromium cast iron roll general cast iron roll arrangement in the eutectic carbide M3c constitute a continuous phase and therefore more brittle. The eutectic carbide C3 M7 in high chromium cast iron is an intermittent phase, which reduces the brittleness and improves the resistance. With the different chromium containing layer and heat treatment process, the hardness of high chromium cast iron roll is very wide, 55 ~ 95HSD.

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