Materials Science and Engineering Commons^™

Assessing Mechanical Performance Of Dissimilar Steel Systems Made Via Wire-Arc Additive Manufacturing, Obed Daniel Acevedo

Masters Theses

Hot stamping is part of a specific type of metalworking procedure widely used in the automotive industry. This research seeks to help make hot stamp tooling component production more cost-effective by using large-scale additive manufacturing. Additive manufacturing can produce dissimilar steel components that can be more cost-effective and time-efficient and allow for complex geometries to be made. A dissimilar steel system consisting of 410 martensitic stainless steel and AWS ER70S-6 mild steel is proposed to make hot stamps, making them more cost-efficient. However, the material interface's mechanical behavior in 410SS-mild steel additively manufactured material systems is not well understood. This …

Inclusion Control In Steel Castings, Koushik Karthikeyan Balasubramanian

Masters Theses

“Non-metallic inclusions are mainly comprised of oxides, sulfides, and nitrides, and are formed in liquid steel during the melting and refining process, as a result of reoxidation, worn-out refractories, or entrained slag. The notch toughness of high strength steels is particularly susceptible to the type, number, size, and distribution of non-metallic inclusions. High manganese and aluminum austenitic steels, or Fe-Mn-Al steels, have gained much interest in the military and automotive sector because of their excellent combinations of high strength and toughness. However, these steels are subject to both oxide bifilms and aluminum nitride, AlN, inclusions which form during melting and …

Carbon Transfer From Magnesia-Graphite Ladle Refractories To Ultra-Low Carbon Steel, Andrew Arthur Russo

Masters Theses

"Ultra-low carbon steels are utilized in processes which require maximum ductility. Increases in interstitial carbon lower the ductility of steel; therefore, it is important to examine possible sources of carbon. The refractory ladle lining is one such source. Ladle refractories often contain graphite for its desirable thermal shock and slag corrosion resistance. This graphite is a possible source of carbon increase in ultra-low carbon steels. The goal of this research is to understand and evaluate the mechanisms by which carbon transfers to ultra-low carbon steel from magnesia-graphite ladle refractory.

Laboratory dip tests were performed in a vacuum induction furnace under …

A Study On Non-Metallic Inclusions In Foundry Steel Process, Marc Leonard Harris

Masters Theses

"The effects of sample area and automated SEM/EDS feature analysis parameters (step size, magnification and threshold) on nonmetallic inclusion characterization results has been investigated and optimized. A post-processing program was developed to automatically determine average inclusion chemistry, total element concentrations within inclusions, and for generating joint ternary diagrams with size visualization for representing nonmetallic inclusion populations. Using these tools the evolution of nonmetallic inclusions was examined for 4320 steel at a participating industrial steel foundry. The steel was sampled throughout electric arc furnace melting through ladle refining to the final casting where an in-mold sampling procedure was developed to procure …

Development And Use Of A Simple Test Method To Evaluate Reheat Cracking Sensitivity In The Weld Deposit Region Of A Submerged Arc Weld, Maxwell Calder Trent

Masters Theses

Several fabricators have recently noted the occurrence of reheat cracking in the weld deposits of 2¼[ two and one fourth]Cr‑1Mo‑¼[one fourth]V (22V) during the fabrication of pressure vessels used in the petrochemical industry. Due to increased oversight now required during fabrication of already expensive pressure vessels, studies have commenced worldwide in an effort to identify root causes and formulate mitigating actions to weld reheat cracking issues. The Materials Joining Group (MJG) at the University of Tennessee at Knoxville (UTK) have adapted an existing reheat cracking test originally developed for use with alloys similar to 22V. This original C‑Ring test was …