Accession Number : AD0805841

Title :   RESEARCH AND DEVELOPMENT OF MATHEMATICAL-ANALYTICAL TECHNIQUES IN CASTING.

Descriptive Note : Final technical rept. 1 Dec 64-30 Jun 66,

Corporate Author : TRW INC CLEVELAND OH MATERIALS AND PROCESSES DEPT

Personal Author(s) : Brokloff, John E. ; Kortovich, Charles S.

Report Date : OCT 1966

Pagination or Media Count : 183

Abstract : The objective of the program was to utilize computerized mathematical-analytical techniques to determine the influence of investment casting variables on the mechanical properties of superalloy Inco 713C. Mathematical-analytical techniques are potentially useful as a problem solving tool and can contribute to the advancement of cast metals technology. Stepwise multiple regression analysis and statistically designed experimentation were employed. Computerized multiple regression analysis on metallurgical data from production heats developed relationships of tensile and 1800 F stress-rupture properties to alloy chemistry and melting parameters. The elements chromium and columbium plus tantalum were determined to be most influential towards strength and 1800 F life. Melting variables failed to achieve the significance of chemistry factors in the property equations. Computerized multiple regression analysis of data from statistically designed casting equations for Inco 713C and further illustrated the potential breadth of the mathematical-analytical technique. Wedge shaped keel blocks, sphere, tee, and I forms, and simulated turbine engine shapes were cast. The mathematical-analytical technique exhibited the ability to distinguish easily the most predominant variable; for example, mold preheat was denoted as a detriment toward 1800 F stress-rupture life, because preheat enhanced the formation of porosity within the castings poured. A small grain size was also predicted to reduce 1800 F rupture life and elongation.

Descriptors :   (*REGRESSION ANALYSIS, COMPUTER PROGRAMS), (*CASTING, REGRESSION ANALYSIS), (*NICKEL ALLOYS, CASTING), MECHANICAL PROPERTIES, TENSILE PROPERTIES, STRESSES, CHROMIUM, NIOBIUM, TANTALUM, FAILURE(MECHANICS), MELTING, MATHEMATICAL ANALYSIS, ELONGATION, STATISTICAL ANALYSIS, DIGITAL COMPUTERS, ADDITIVES.

Subject Categories : Metallurgy and Metallography
      Fabrication Metallurgy
      Statistics and Probability
      Computer Programming and Software
      Computer Hardware

Distribution Statement : APPROVED FOR PUBLIC RELEASE