Compacted/vermicular graphite cast iron for orbital or fixed scroll and manufacturing method of orbital or fixed scroll using the same

Abstract

Compacted/vermicular (CV) graphite cast iron for an orbital or fixed scroll and a method for manufacturing an orbiting or fixed scroll using the same are provided. The CV graphite cast iron may includes C: 3.4˜3.9%, Si: 1.7˜2.6%, Mn: 0.2˜0.8%, P: 0.02˜0.07%, S: 0.01˜0.03%, Ti: 0.02˜0.1% by weight ratio, with the remainder including iron (Fe) and other impurities. A CV ratio may be 50% or more.

What is claimed is: 
     
         1 . Compacted/vermicular (CV) graphite cast iron for at least one of an orbiting scroll or a fixed scroll, comprising C: 3.4˜3.9%, Si: 1.7˜2.6%, Mn: 0.2˜0.8%, P: 0.02˜0.07%, S: 0.01˜0.03%, Ti: 0.02˜0.1% by weight ratio and iron (Fe) comprising a remainder, the cast iron having a CV ratio greater than or equal to 50%. 
     
     
         2 . A method for manufacturing an orbiting scroll or a fixed scroll, the method comprising:
 mixing raw materials including C: 3.4˜3.9%, Si: 1.7˜2.6%, Mn: 0.2˜0.8%, P: 0.02˜0.07%, S: 0.01˜0.03%, Ti: 0.02˜0.1% by weight ratio and iron (Fe) comprising a remainder, and smelting a first molten metal;   injecting a nodularizer into the first molten metal to obtain a second molten metal;   injecting a denodularizer into the second molten metal including the nodularizer to obtain a third molten metal;   casting the third molten metal including the denodularizer in a mold to obtain a semi-product; and   machining the semi-product to final dimensions to have a final shape.   
     
     
         3 . The method of  claim 2 , wherein injecting a nodularizer into the first molten metal comprises injecting a rare earth element silicon magnesium alloy into the first molten metal. 
     
     
         4 . The method of  claim 3 , wherein injecting a rare earth element silicon magnesium alloy into the first molten metal comprises injecting FeSiMg6RE1 into the first molten metal. 
     
     
         5 . The method of  claim 3 , wherein injecting a nodularizer into the first molten metal comprises injecting the nodularizer in an amount of 0.5˜0.9% of a weight of the first molten metal. 
     
     
         6 . The method of  claim 2 , wherein injecting a denodularizer into the second molten metal comprises injecting the denodularizer while injecting the second molten metal into the mold. 
     
     
         7 . The method of  claim 2 , wherein injecting a denodularizer into the second molten metal comprises injecting the denodularizer including Si, S, O, and Al as principal ingredients. 
     
     
         8 . The method of  claim 7 , wherein injecting a denodularizer into the second molten metal comprises injecting the denodularizer such that a content of the denodularizer is 0.01˜0.02% of a mass of the second molten metal. 
     
     
         9 . The method of  claim 2 , wherein injecting a nodularizer into the first molten metal further comprises injecting a barium silicon iron alloy as an inoculant. 
     
     
         10 . The method of  claim 9 , wherein injecting a barium silicon iron alloy comprises injecting FeSi72Ba2 as an inoculant. 
     
     
         11 . The method of  claim 9 , wherein injecting a barium silicon iron alloy as an inoculant comprises injecting the inoculant in an amount of 0.4˜1.0% of a mass of the second molten metal.