Engineering Commons^™

A Study Of High Strength, Heat Treated Plain Carbon Steels, Ing Shing Chien

Masters Theses

"This work was undertaken as the initial step in a program of studying brittleness in carbon steel that has been heat treated to high strength levels.

The trend in modern technology is toward higher tensile strengths. In practice, only alloy steels are commonly heat treated to very high strength levels. AISI 4340 is one of the more commonly used steels when high strength is desired. It is also becoming almost standard practice to use some of the tool steels or highly alloyed maraging steels for high strength structural components.

For this study high strength in a heat treated steel is …

The Thermodynamics Of The Zno-Fe₂O₃-Fe₃O₄ System, Dennis George Dreyer

Masters Theses

"A study was made of the ZnO-Fe₂O₃-Fe₃O₄ system at 1200ºC using oxygen pressures between 0.1 and 1x10⁻⁴ atmospheres. The results of this study were used to calculate the activities of ZnO, Fe₂O₄, and Fe₃O₄ in the spinel solid solution region of this ternary system. The activities of ZnFe₂O₄ and Fe₃O₄ across the pseudo-binary system were then calculated. The activities of the components in both the ternar and pseudo-binary systems exhibited large positive deviations from Raoult's Law, being more pronounced at the higher Fe₃O₄ content. The free energy, enthalpy, and entropy of mixing of the pseudo-binary system ZnFe₂O₄-Fe₃O₄ at 1200ºC were …

Synthesis And Structural Determination Of Intermetallic Compounds In The Fe-Ho System, Gerald J. Roe

Masters Theses

"The intermediate phases in the holmium-iron system were investigated by means of X-ray diffraction and metallographic examination. The intermediate phases identified by X-ray diffraction data were HoFe₂ , HoFe₃ , HoFe₅, and Ho₂Fe₁₇.

A new intermediate phase, HoFe₃, was found. HoFe₃ was indexed as hexagonal with lattice parameters of a = 5.084 Å and c = 24.45 Å, and was thought to be of the space group R3̄̄m.

HoFe₂ was formed by a peritectic reaction and its solidus was estimated to be between 1325°C and 1340°C. suggested to be a congruent melting intermetallic compound with a melting point below 1340°C. …

A Study Of The Effect Of Magnetite Additions To Shell Molds On The Surface Quality Of Low Carbon Steel Castings, Robert C. Tooke

Masters Theses

"Shell molds containing additions of ten to fifty percent magnetite, Fe₃O₄, of various particle sizes were cured by induction heating. For comparison, regular shell molds were made using silica and zircon sand. Low carbon steel was cast into all of the molds.

Castings produced from the regular shell molds exhibited poor surfaces due to mold expansion. Magnetite additions eliminated the expansion defects from the casting surfaces.

Excellent surfaces were obtained on the low carbon steel castings with proper selection of the magnetite particle size and the percent of magnetite added. Improper combinations of size and amount …