College - Author 1
College of Engineering
Department - Author 1
Materials Engineering Department
Degree Name - Author 1
BS in Materials Engineering
Date
6-2020
Primary Advisor
Blair London, College of Engineering, Materials Engineering Department
Abstract/Summary
Carlton Forge Works, an industry leader in the manufacture of rolled rings, has observed anomalous grain structures in parts made from Inconel 718 and Waspaloy. These take the form of unusually large grains at the surface of the rings, causing them to fail industry grain size standards. Grain size testing is a critical part of evaluating parts before they are used as grain size and structure control many mechanical properties including creep resistance, low and high cycle fatigue life, and yield strength. These unusually large grains are only present within the first tenth of an inch of the surface of the part, so parts that would seem to have lower mechanical properties due to a poor grain structure meet the required properties due to having a passing grain structure in the bulk of the material. This project seeks to quantify precisely how deep the anomalous microstructure is present and determine where on the parts it is present by testing multiple areas on each part. Some initial micrographs were obtained, but no concrete conclusions were able to be drawn because of the COVID-19 situation preventing lab access. Possible causes for effect are discussed, including compositional variance, thermal gradients during processing, and grain growth during finishing passes. Methods for investigating each of the proposed causes are also put forward
URL: https://digitalcommons.calpoly.edu/matesp/221