The present work covers an analysis of the fundamental thermal phenomena which take place when 'buoyant', solid additives are injected into steel or hot metal for deoxidation or desulphurization purposes. For low melting point additives such as aluminum (for steel deoxidation) or magnesium (for hot metal desulphurization), it is found that a solid shell of the melt material will tend to fuse onto the object. Very often, the encasing shell will delay the rapid dispersion of the additive. / Two industrial methods which can be used to improve additive dispersion are the wire feeding and bullet shooting techniques. A thermal analysis of these two processes was carried out in the present study. / Aluminum wires of 6.4 to 15.9 mm in diameter were fed into steel melts while their 'apparent' weights were monitored with a novel piece of equipment. It was determined that the maximum depth of penetration of an aluminum wire fed into molten steel can be expressed as: / (DIAGRAM, TABLE OR GRAPHIC OMITTED...PLEASE SEE DAI) / The thermal aspects of the bullet shooting method were also simulated with the above-mentioned apparatus. It was found that the aluminum was only dispersed when the shell in the vicinity of the ends of a bullet had melted back. Since the time required to melt back the shell is inversely proportional to the superheat of the melt, molten aluminum cores encased in solid shells will resurface if the superheat is too low. It was shown that by selectively applying an appropriate thermal resistance onto the surface of a bullet, this problem can be eliminated.

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Thesis (Ph. D.)--University of Michigan. / Cover title. "By W.L. Fink and E.D. Campbell." "Reprint from the May, 1926, issue of Transactions of the American Society for Steel Treating." "Selected bibliography": p. 750-752.

Thesis (M.S.)--University of Wisconsin--Madison. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 116-117).

Thesis (M.S.)--University of Wisconsin--Madison, 1961. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 65-66).

Thesis (M.S.)--University of Wisconsin--Madison, 1963. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 25-26).

Thesis (M.S.)--University of Wisconsin--Madison, 1963. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 37-38).

No description available.

No description available.

The research work in this thesis involves an experimental and theoretical investigation for high speed machining of AISI 4140 medium carbon steels and AISI D2 tool steels which are classified as being difficult to machine materials. An experimental program was carried out to determine the cutting forces, chip formation, the secondary deformation zone thickness and surface roughness at different cutting speeds using a 0.4mm and 0.8mm nose radii ceramic tools and -7?? rake angle for annealed (virgin) AISI 4140 and heat treated AISI 4140 steel. Another series of experiments was carried out on the annealed (virgin) and heat treated AISI D2 with 0.4mm, 0.8mm and 1.2mm nose radii CBN (Cubic Boron Nitride) tools under various cutting conditions. A theoretical model is developed by taking into account the flow stress properties of the AISI 4140 (0.44% carbon content) to use with the Oxley Machining approach. To find the flow stress data for AISI D2 tool steel, the Johnson and Cook empirical constitutive equation is used as the constitutive model. In addition, the magnitude of tool radius should be also considered to determine the prediction of cutting performances. To account for the effect of nose radius edge in hard machining, a simplified geometrical method is used to model the parameters for application in the Oxley Model and works for the cutting conditions considered here. These extensions to the Oxley machining theory were verified by experimental results. These results show a good agreement between the Oxley machining theory and hard machining experiment at data. The research work described in this thesis provides useful data for hard machining conditions.