Gray iron for industrial use is an complex alloy of iron,carbon and silicon which refers to a range of cast irons which solidify with a eutectic.In order to improve the performance of gray iron,steel casting manufacturers,investment casting manufacturers and grey iron casting manufacturers often add different kinds fo alloy elements to produce alloy castings for different use.
Consequently these alloys should be considered ternary Fe-C-Si alloys.Despite this, the principles of cast iron solidification are understood from the binary iron-carbon phase diagram,where the eutectic point lies at 1154°C and 4.3 wt% carbon.The term grey is used because of the colour of the fracture surface if a piece is broken.If molten cast iron is allowed to cool normally the carbon comes out of solution and forms flakes of graphite which run through the ferrite/pearlite matrix,hence the alternative term, flake graphite iron.These flakes are at the microscopic level,the ends of which form stress points in the cast iron.If cast iron is subject to a compressive load these stress points are not particularly detrimental and flake graphite cast iron is excellent under compressive load,although its use is more limited in situations where it is subject to bending or shock loading.
Grey cast iron came into its own during the industrial revolution when improved production methods and understanding of the metallurgy led to more a reliable material that could be cast into an increasing number of different shapes and section thicknesses.The Victorian era saw an explosion in the use of cast iron and that has continued to this day due to the combination of the ability to cast complex shapes at low cost compared to other production methods and materials.
Cast iron can be divided into seven types,and grey iron casting,and ductile iron castings are common for use.They are widely used in the construction machinery casting,mining machinery casting, cast iron pulley,cast iron valves and so on.
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