Grain Refinement in Steel Castings PDF Download

Author: Ronald Abraham Kurtz
Publisher:
ISBN:
Category :
Languages : en
Pages : 70

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Author: CASE INST OF TECH CLEVELAND OHIO DEPT OF METALLURGY.
Publisher:
ISBN:
Category :
Languages : en
Pages : 81

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Inoculation techniques were developed to refine the as cast structure of high strength steel. Titanium was found to be the most effective inoculant. Large titanium additions (0.6%) form sulfides which embrittle the steel. Small titanium additions (0.1%) together with controlled superheat and mold design may produce significant refinement. Under these conditions the structure of unidirectionally solidified castings was changed from columnar to equizxed and the reduction in area increased by approximately 25% for specimens oriented vertically to the direction of heat flow and increased about 75% for horizontally oriented specimens. A small improvement in reduction in area of keel block castings was obtained by lthis method. Some improvement in toughness was also obtained by this grain refinement. The influence of vacuum melting on the cast structure of the same steel was investigated. A hypothesis explaining the mechanism of refinement by vacuum melting was proposed. (Author).

Author: A. Pradhan
Publisher:
ISBN:
Category :
Languages : en
Pages : 8

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Author: Steel Founders' Society of America
Publisher:
ISBN:
Category : Solidification
Languages : en
Pages : 148

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Author: Dustin Alan Arvola
Publisher:
ISBN:
Category :
Languages : en
Pages : 153

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"The goal of this research project is to develop an industrially viable melting process that will control the crystallization macrostructure of austenitic grades of cast steels. Titanium nitride (TiN) has proven to be an effective grain refiner of austenite. Theoretical simulation and experimental application has led to the development of a repeatable grain refining melt process for austenitic stainless steel alloys. Grain refinement of the as-cast structure of Cr-Ni stainless steel alloys solidified with primary FCC, BCC and dual FCC/BCC phases was studied experimentally. Refinement was achieved in both cast ferritic and austenitic grades. Dual solidification of FCC/BCC phases resulted in an unrefined macrostructure. It is proposed that solidification sequence can limit the grain refining capability of heterogeneous nuclei. Two inoculation-based melt practices were developed to study grain refinement in cast austenitic stainless steels. The first includes in-situ formation of TiN on to Mg-Al spinel oxides, and the second involves master alloy additions containing preformed TiN. The master alloy method extended the equiaxed zone and improved the distribution of TiN in the casting. The in-situ method showed more effective grain size refinement. The effect of the developed grain refining melt practice on the properties of cast superaustenitic stainless steel (similar to CK3MCuN) was examined. Heat treatment had no effect on the as-cast grain size. The grain refined alloy exhibited a reduction in segregation after heat treatment; an increase in ultimate tensile strength (+11%), yield strength (+13%), ductility (+8%), hardness (+2%), pitting corrosion; a decrease in impact strength and intergranular corrosion rate in comparison to the unmodified, base alloy"--Abstract, page iv.

Author: G. K. TURNBULL
Publisher:
ISBN:
Category :
Languages : en
Pages : 1

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Various substances were added to molten low carbon steel in an attempt to develop methods by which the as-cast structure of steel could be grain-refined. The selection of the additions was based either on their capability to provide finely distributed centers for heterogeneous nucleation or on their potency of producing appreciable constitutional supercooling to interrupt continuous growth of the first formed crystallites. Considerable effort was directed toward developing suitable means of delineating the as-cast grain size from various structural features which persisted through the allotropic transformation when cooling to room temperature. As inoculants, TiC and V-B were particularly effective, while Nb and Ti proved to be suitable solute additions to interrupt grain growth. Mechanical properties were determined for those castings in which appreciable grain refinement of the as-cast structure was obtained. Generally, an improvement in strength was obtained which, however, was accompanied by a loss in ductility and notch toughness. (Author).

Author: Yuqing Weng
Publisher: Springer Science & Business Media
ISBN: 3540772308
Category : Technology & Engineering
Languages : en
Pages : 588

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This book discusses results of the New Generation Iron and Steel Materials research project funded over the last ten years. It thoroughly describes theoretical achievements in ultra-fine grain steel and its refinement. It also discusses progress in related areas of engineering and technology. The author has been engaged in the research of new generation structural materials for the last twelve years being Chief Scientist of three national research programs in China.

Author: Peter F. Wieser
Publisher:
ISBN:
Category :
Languages : en
Pages : 95

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The relation of dendrite structure, nonmetallics and microporosity to solidification time and refinement by inoculation was investigated and correlated to mechanical properties of AISI 4335 steel castings. The dendrite spacing is determined by solidification time and significantly influenced by solute content. Titanium and boron effectively refine the secondary dendrite spacing; selenium tellurium and sulfur have the opposite effect. Titanium inoculation also nucleates equiaxed dendrites thereby reducing or eliminating the columnar dendritic structure. Increasing solidification time and amount or size of nonmetallics decrease the ductility. Improvements in ductility from grain refinement by either inoculation or shorter solidification time are caused by improved distribution or reduction of the size of nonmetallics. Microprobe analysis indicates no significant differences in the segregation behavior of the elements manganese and chromium from inoculation. A hypothesis concerning the formation of dendrite arms was postulated based upon measurements of solute distribution and existing theories of dendrite arm formation. (Author).

Author: P. WIESER
Publisher:
ISBN:
Category :
Languages : en
Pages : 82

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Techniques for the quantative evaluation of refinement of a high strength cast steel have been evolved and used to test the effectiveness of various inoculants in achieving microstructural and macrostructural refinement. Of the various materials tested only titanium additions produced significant refinement of both the micro and macrostructure. Comparison of the tensile properties of the basic steel with that of a refined steel shows that large additions (0.2-0.6 wt%) of titanium are sufficient to decrease the reduction in area sharply. Further data on castings partially refined with small (0.10 wt%) titanium additions indicate that an improvement in reduction of area is obtained compared to the results with a columnar structure solidified under similar thermal conditions. (Author).

Author: Roger Lumley
Publisher: Elsevier
ISBN: 0857090259
Category : Technology & Engineering
Languages : en
Pages : 862

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Book Description
Aluminium is an important metal in manufacturing, due to its versatile properties and the many applications of both the processed metal and its alloys in different industries. Fundamentals of aluminium metallurgy provides a comprehensive overview of the production, properties and processing of aluminium, and its applications in manufacturing industries. Part one discusses different methods of producing and casting aluminium, covering areas such as casting of alloys, quality issues and specific production methods such as high-pressure diecasting. The metallurgical properties of aluminium and its alloys are reviewed in Part two, with chapters on such topics as hardening, precipitation processes and solute partitioning and clustering, as well as properties such as fracture resistance. Finally, Part three includes chapters on joining, laser sintering and other methods of processing aluminium, and its applications in particular areas of industry such as aerospace. With its distinguished editor and team of expert contributors, Fundamentals of aluminium metallurgy is a standard reference for researchers in metallurgy, as well as all those involved in the manufacture and use of aluminium products. Provides a comprehensive overview of the production, properties and processing of aluminium, and its applications in manufacturing industries Considers many issues of central importance in aluminium production and utilization considering quality issues and design for fatigue growth resistance Metallurgical properties of aluminium and its alloys are further explored with particular reference to work hardening and applications of industrial alloys