INVESTIGATION OF SOLIDIFICATION OF HIGH-STRENGTH STEEL CASTINGS
Abstract
Analytical and experimental work on microsegregation and dendrite structure in a series of iron base alloys is summarized. Experimental work is on iron-nickel alloys, iron-4% phosphorous alloy, iron-25% copper alloy, and iron-nickel carbon alloys. A new computer analysis for microsegregation is presented, with detailed numerical results given for iron-26% nickel alloy, iron-10% nickel alloy, and iron-4% phosphorous alloy. Results agree reasonably well with experiment provided the dendrite arm spacing used in calculation is less by a constant 'correction factor', g, than that measured (for example g nearly equal to 0.40 for cylinder model, secondary dendrite arm spacing). It is concluded the need for the correction factor arises primarily because the model employed for calculation does not account for 'ripening' during solidification. Structures of the various alloys studied are presented; in some, the dendrite morphology is strongly plate-like; in others, it is 'fibrous'. Over a range of cooling rates from 0.001 C/sec to nearly 1,000,000 C/sec dendrite arm spacing of iron-26% nickel alloy is linearly related to a single power of cooling rate. It is concluded that the dependency results from the predominant effect of 'coarsening' in determining final dendrite arm spacing.
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 01, 1967
- Accession Number
- AD0661056
Entities
People
- H. D. Brody
- Merton C. Flemings
- R. V. Barone
Organizations
- Massachusetts Institute of Technology