Metallurgy Commons^™

Improving Cast Steel Rail Coupler Fatigue Resistance Through Local Wire-Arc Additive Manufacturing, Andrew M. Bunge

Dissertations, Master's Theses and Master's Reports

Every year, thousands of cast-steel railcar couplers suffer from corrosion-initiated fatigue cracking in similar areas of the coupler’s knuckle; between 2015 and 2018 about 90,000 knuckles were replaced, otherwise these couplers would have been at risk for unexpected failures. These types of couplers have been common in industrial use as early as 1932, hence it is desirable for a countermeasure to the fatigue cracking that does not involve significantly altering the geometry or casting process. Wire arc additive manufacturing (WAM) is a developing technology which boasts the ability to produce complex near-net-shape components; however, less attention has been paid to …

Characterization Of Hydrogen Embrittlement Sensitivity In High Hardness Steels, David Ahlen Salley

Theses and Dissertations

High hardness steels can be affected by delayed brittle cracking often attributed to hydrogen embrittlement. Improved resistance to hydrogen embrittlement would be beneficial to many industries including military, automotive, and high-rise construction. While other prevention methods include coating, trapping, and barriers, design efforts in this study were focused on improving intrinsic properties to be more resistant to hydrogen embrittlement. Four alloys targeting 477 – 534 HB were designed and produced in-house and compared against a commercial grade 500 HB alloy. Charpy V-notch (CVN) impact toughness and tensile specimens were made according to ASTM E23 and ASTM E8 to characterize mechanical …

Austenitic, Duplex, And Lean Duplex Stainless Steel Critical Pitting Temperature In Simulated Concrete Environment, Bobby Giebel

Williams Honors College, Honors Research Projects

In this work, the critical pitting temperature (CPT) will be observed for a selection of austenitic (316LN and 24100) and duplex (2205), and lean duplex (2304, 2001) stainless steels in simulated concrete pore solution. To study the influence of temperature on the pitting stability of the stainless steels, three temperatures were tested: 25oC, 45oC, and 65oC for cyclic potentiodynamic polarization (CPP) and electrochemical impedance spectroscopy (EIS). Electrochemical properties of the interfaces we studied via EIS analysis. Kinetics were studied via CPP testing. To reveal the critical pitting temperature of the stainless steels, cyclic thermammetry was used. Characterization of the pits …

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 …

Galvanic Corrosion In Aluminum/Steel Joints, Maegan Saul

Williams Honors College, Honors Research Projects

As car manufacturers seek to use lighter weight materials, aluminum is being more commonly used in the construction of vehicles. However, the strength of steel cannot be matched and both metals are necessary, leading to the joining of dissimilar metals. This connection of different metals leads to a galvanic coupling and subsequent corrosion of the less noble metal. This project aims to observe the corrosion and galvanic coupling behavior of aluminum alloys and carbon steel so that a model may be produced which can accurately predict the expected responses of the metals in various environments. Better, more accurate modeling of …

Optimization Of The Practice Of Slow Cooling Steel Bars: A Redesign And Modernization Of Materials, Eryn Johnston

Mechanical Engineering Undergraduate Honors Theses

Throughout the process of steel making, certain grades of steel are a higher risk for defects caused by the inability to quickly diffuse hydrogen through the steel when cooled to room temperature at a normal rate based on the ambient air temperature. To reduce the hydrogen flaking defects that are caused due to hydrogen entrapment in the steel, the process of slow cooling is utilized. This process reduces the cooling rate of steel bars by keeping them at a higher temperature for extended periods and in turn gives the hydrogen a chance to fully dissipate from the steel. In many …

Temper Response Of A Vanadium Microalloy Steel, Bradley W. Hostetler

Materials Engineering

This investigation details the effect of a quench-and-temper processing treatment on the mechanical properties of a microalloy steel being considered for use as a pipeline flange. Microalloy steels are normally processed via Thermo-Mechanically Controlled Processing (TMCP) due to the increased strength from ferrite grain refinement; however, the geometry of a pipeline flange requires post processing beyond TMCP which diminishes the strengthening effect provided by TMCP. The purpose of this research project is to determine the mechanical properties produced when a vanadium microalloy steel is quenched and tempered. The two major considerations are the effect of tempering time on properties and …

Process Development And Implementation For The Imaging Of Heat Treated A2 Steel For Consolidation Into An Atlas, Jessica Roberts

Senior Honors Projects, 2010-2019

Material processes, properties, and microstructure are interconnected, often visualized as the points of a triangle. Changing the process a material goes through will in turn change the properties and microstructure of that material. In materials research and education (specifically with metals), comparison between research or experiment results and scholarly-accepted results is important. When reading textbooks addressing different properties of metals and the process of metal treatment, images are often shown of the various microstructures associated with each property or process stage. The difficulty comes in trying to compare the stages or properties to one another; often different materials and processes …

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 …

The Examination Of Stress Corrosion Cracking In High Strength Carbon Steel Through Combined Mechanical-Electrochemical Testing, Jacob Sines

Williams Honors College, Honors Research Projects

Through the analysis of materials and environments seen in industry a better understanding of the fundamentals behind degradation mechanisms can be observed. The scope of this project was to better understand the fundamentals behind the degradation of high strength pipeline steels in a lab setting to simulate an environment seen in industry. Specifically the degradation mechanisms of high and nearly neutral pH stress corrosion cracking were examined in environments that simulated oil and gas pipelines buried in soil. Experimentation was carried out utilizing X65 carbon steel specimen, a Gamry potentiostat, a CORTEST proof ring, a CORTEST slow strain rate machine, …

An Intercritical Heat Treatment Study Of High Strength, Microalloyed Ferrous Open Die Forgings, Kelly Elizabeth Stewart

Materials Engineering

High strength, low alloy steel is most commonly utilized in plate or sheet form-with a thickness under 4 in, one unconventional application however, is open die forging where cross-sectional area can be as large as 9.5 in by 11.5 in. When forging to larger section size than one would thermo-mechanically roll sheet steel, a new set of complications, such as variation in microstructure and mechanical properties, arise. This study investigates the heat treatment and processing options needed to negate the inherent microstructural irregularity and Charpy V-Notch (CVN) toughness variation. Intercritical heat treatment—normalizing and then quench and tempering above the A …

The Effects Of Heat Treatment On The Grain Growth, Phase Evolution, And Hardness Of Newly Developed Steel-Based Hardfacing Alloys For Industrial Applications, Renee Kuzniar

Materials Engineering

Steel-based hardfacing alloys are welded onto the outside diameter of tool joints in three beads with a slight overlap between welds for underground drilling to prolong the tool joints’ life. Current hardfacing alloys have a shortened life due to cracks occurring in neighboring weld beads. To decrease cracking, the effects of composition and heat treatment on the microstructure was investigated on five alloys. Five small arc-melt circular ingots roughly 1.4 x 0.3 inches were produced. Each sample had varying amounts of C, B, Cr, Mn, Mo, Nb, Si, Ti, V, and W. The carbon levels in the alloys were .91wt%, …

Bacterial Growth On Metal And Non-Metal Surfaces In A Static Bioreactor, Rolan Yuk Loong Liong

Master's Theses

Research was conducted to observe bacterial growth on the surface of metals in a static bioreactor. Metal and non-metal samples were subjected to bacterial exposure (1 day and 9 days). The metal samples were surface treated prior to bacterial exposure. The microstructures of the surface treated samples were analyzed by optical microscopy. After exposure, the microstructures of the samples were analyzed by scanning electron microscopy (SEM). The analysis suggested that microbial attachment on the surface was related to the underlying microstructure of steel. The preferential attachment of microbes could potentially be influenced by cathodic and anodic regions created by the …

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 …

Characterization Of Iron Oxides And Atmospheric Corrosion Of Steel, Sei Jin Oh

Physics Theses & Dissertations

The study of corrosion behavior was performed using three different analytical techniques, which provided information on the formation, development and layering of iron oxides on the corrosion products as a function of atmospheric conditions, exposure time and type of steel. In particular, the protective layer formed on weathering steel was investigated as a function of different amounts of alloying elements in the steel, atmospheric conditions and exposure times. Combined together, the results provided a better understanding of the atmospheric corrosion behavior of steel, and formed a part of database of the atmospheric corrosion characteristics.

Accurate characterization of the iron oxides …

Investigation Of Inclusions In Armco Ingot Iron, Edwin J. Duncan

Bachelors Theses and Reports, 1928 - 1970

Various chemical and electrolytic separation methods were investigated in an attempt to separate the in­clusions in Armco ingot iron. Residues obtained were X-rayed for identification purposes. The microstruc­tures of this iron were studied with the object of de­termining the relative sizes, locations, and possible compositions of the inclusions.

Studies Of Tempering Behavior Of Steel X-9165 Of N-A-X 9100 Series, James A. Ndulue

Bachelors Theses and Reports, 1928 - 1970

One of the reasons why steel is the most versatile of all the metals available for engineering applications is because of the wide range of properties that can be obtained from it by proper heat treatment.

Electroplating Of Chromium, Nickel And Copper Upon Titanium, Stanley O. Fong

Bachelors Theses and Reports, 1928 - 1970

Recently, there has been a great amount of research work done on the metal titanium. Since it is a light weight metal, with unusual strength and good resistance to corrosion, it may be a possible substitute for aluminum and magnesium alloys, or steel.

The Influence Of Copper Upon The Age Hardening Properties Of Steel, Andre Rey

Bachelors Theses and Reports, 1928 - 1970

The virtues of alloy steels have been widely publi­cized in both technical literature and everyday adver­tising. Nearly everyone possessing a slight knowledge of metallurgy knows the beneficial effects of chromium in the manufacture of stainless steels, or the importance of nickel, molybdenum, vanadium, and other common elements used to alloy steels.

Benefication Of A Tungsten Ore, James Alexander Shaffer Jr.

Bachelors Theses and Reports, 1928 - 1970

Tungsten is a metal of high strategic value in the defense effort. It is used chiefly to improve creep strength in steels, although a significant percentage enters into the manufacture of cemented carbide tool bits. Therefore, in this age of mechanized warfare, quality and quantity of defense production depend greatly on tungsten.

The Electrolytic Polishing Of Steel In Solutions Of Sulphuric And Phosphoric Acids, Joseph W. Tripp

Bachelors Theses and Reports, 1928 - 1970

The process of cleaning and pickling the surfaces of steel objects by electrolytic methods has been known and applied since about 1920; the fact that under certain con­ditions these surfaces acquired a brilliant luster was noted as early as 1928.

An Isothermal Study Of An S.A.E. 6150 Steel, Tom Liss, C. Arentzen

Bachelors Theses and Reports, 1928 - 1970

The purpose of this thesis is to set forth the method followed, the laboratory procedure practiced, the results obtained, the conclu­sions drawn, and the recommendations proposed as a consequence of a metallographic study of the isothermal transformation of an S.A.E. 6150 steel.

An Investigation Of Silicon Impregnation Of Low-Carbon Steels, Thomas E. Groce

Bachelors Theses and Reports, 1928 - 1970

A problem of metallurgy during the last part of the Nineteenth and the early Twentieth Century, and one that stood very near the front, was investigations of methods to produce a non-corrosive surface on iron and steel without affecting the physical properties of these base metals.

Aluminum - Bronze Compacts And Their Possible Use As A Bearing Material, Donald J. Mcmaster

Bachelors Theses and Reports, 1928 - 1970

In the modern aspect of powder metallurgy, the first use of a sintering process was in making filaments for incandescent electric lamps.In the short while from the day of Edison to the pres­ent, the science of working with metal powders has advanced by leaps and bounds.

Leaching Of Low Grade Rhodochrosite, E. D. King

Bachelors Theses and Reports, 1928 - 1970

Although there are many uses for manganese today, none of them approaches its importance as a deoxidizing agent in the manufac­ture of steels. Without manganese the steelmaking in­dustry would be very seriously handicapped. The metal­lurgy of manganese has been developed around the high-grade ores, and unfortunately, our reserves of high-grade ores are very limited.

An Investigation Of A Particular Weldment Failure, Byron Clow

Bachelors Theses and Reports, 1928 - 1970

Two sets of weld-test coupons, supposedly made under identical conditions, were submitted to this institution last year for approval and certification under the A.S.M.E. Welder's Qualification Code. The first set of coupons was unsatisfactory. The second set, made by the same operators one month later, was satisfactory.

The Corrosion Resistance Of Iron-Tin Compacts As Produced By Powder Metallurgy, Robert W. Gambill

Bachelors Theses and Reports, 1928 - 1970

The art of Powder Metallurgy deals with the preparation of metal powders and their utilization. As a more pertinent definition, the following has been suggest­ed: "Powder Metallurgy is the art of producing metal powders and shaped objects from individual, mixed, or alloyed metal powders, with or without the inclusion of non-metallic consti­tuents".

Electro-Deposition Of Iron From A Chloride Bath, Charles W. Noon

Bachelors Theses and Reports, 1928 - 1970

Iron was electro-deposited from a ferrous chloride bath. Studies were made of deposits formed when current density was varied, and fin­ally when both current density and temperature were changed. An attempt was made to lay the ground work for a long range study of the chloride bath, and to determine the most simple conditions possible for obtaining a smooth, even, and thick deposit.

Age Hardening Of Copper Antimony Alloys, William R. Stern

Bachelors Theses and Reports, 1928 - 1970

A large number of alloys of varying percentages of copper and antimony were prepared. These alloys were treated in various ways which might be expected to produce age hardening. The effect of cold working was studied in the range where the alloys were malleable.

The Effect Of Boron On The Hardenability Of Steel, William J. Foy

Bachelors Theses and Reports, 1928 - 1970

Many attempts have been made to improve iron and steel and their alloys by the addition of boron. The re­sults obtained were not encouraging for the reason that the amount of boron used, generally from 0.2 to 2.0 per cent is altogether too high. This percentage of boron ren­ders the product hard and brittle and of late the experiments with boron in this connection have been practically abandoned.