steel graphitizable

steel graphitizable
Real carbon in the form of graphite
The characteristics of the super high carbon hypereutectoid steel
Friction and wear resistance of materials
Graphitic steel tissue contains a small amount of graphite hypereutectoid steel. According to the different carbon content, can have various steel grades of graphite and its chemical composition range: carbon 1.3%~2.o%; silicon 1.1%~1.5%; manganese O.4%~O.8%; nickel O.4%~1.5%; chromium 0.4%~1.5%; O.2%~O.6% molybdenum.

Steel graphite can be used in the manufacture of hot roll rolling mill, but also can be used for slab, type steel hot rolled strip and rolling mill roughing mill stand. This material due to the organization containing graphite can improve thermal conductivity and lower thermal stress. The hot crack formation and propagation is greatly reduced, improving the wear resistance of the roller and biting ability, extend the service life of the roller. In addition, the material of roll from surface to center the hardness change little can processing deep groove, the groove bottom and the side wall of the same wear resistance. Steel graphite can be self - lubricating bearing material for.

The manufacture of graphite steel roller should take into account the composition, inoculation and heat treatment of the alloy.
(1) alloy composition, increase the content of carbon, increase the amount of carbide in the organization, can make the hardness and wear resistance increase, but the toughness and bending strength decrease. In addition to adjust the number of free graphite, silicon and improve the content of chromium.
(2) inoculant. In as cast to precipitation of graphite, in the molten steel added inoculant. Commonly used inoculant with rare earth, rare earth magnesium, ferrosilicon, silicon calcium alloy.
(3) heat treatment. In order to improve the performance of the graphitic steel roller and further the carbide graphite, in the manufacturing process should be heat treatment. Commonly used heat treatment process 920~950 DEG C normalizing and 700~750 DEG C for tempering. Can also be a 1100~1150 DEG C, the diffusion annealing to improve the carbide shape.
The casting stress can be eliminated by heat treatment and the toughness can be improved.
Finally the organization can be pearlite and carbides, which free graphite amount for O.1%~O.5%. graphite shape is spherical or floc, size is about 8~15ttm.
For example, a can be used for rough rolling of tropical, crude steel roll billet or type of graphite steel material: Ingredients: 1.4% to 1.6% of carbon, silicon 1.O%~1.6%; manganese O.6%~1.O%; chromium O.6%~1.O%; nickel O.6%~1.O%; molybdenum O.2%~O.6%.
Hardness:}tS40~50; tensile strength is more than 600MPa.
The flexural strength is not less than 800MPa; impact toughness was 3.5J/cm.; elongation was 1.O%.