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Subject: Re: A type graphite formation in Grey Iron
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Date: 05/07/03 at 12:12 AM
Posted by: Vikas Goel
In Reply to: Re: A type graphite formation in Grey Iron posted by tarek adel on 05/06/03 at 5:12 AM:
1. BAd effects of D&E type graphite: These types of graphite are small in size and segregated. The samll size does increase strength apparantly, but due to smaller path for carbon diffusion, tendency of ferrite formation around these types of graphite is there due to which strength and hardness are adversely affected. ALthough, if D7E occure without harmful patches of ferrite then this type of graphite can be tolerated.
2. Elimination: Elimination requires a look into the entire melting process, but in a nutshell, the foillowing points are most important for formation of A type graphite. (i) Keep the Carbon Equivalent value at the highest possible for the section thickness in question (ii) Use the correct inoculant for your chemistry and melting practice (iii) use correct quantity of inoculannt (iv) Check the graphitisation potential of liquid metal before inoculation and maintain wihtin a narrow range by pre conditioning if required. Use wedge chill technique for this evaluation.
Hope the suggestions are helpful.
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