Texture strengthening in high-temperature applications such as heat-exchanger materials

Abstract Plastic yielding and flow in metals is dependent on the microscopic process of simple shear along crystallographic planes and directions known as slip. Thus, by altering the crystallographic direction of the stress axis or placing constraints in the direction of plastic flow, anisotropy of yield strength for the same material is observed. This phenomenon is called texture strengthening. The application of this concept to highly anisotropic crystal structures such as the hexagonal group of titanium and zirconium alloys, the former in missile casing and the latter in nuclear reactor fuel tubing, seems obvious. The outstanding example in cubic structures is the case of deep-drawing steel. The R value, the width strain over the thickness strain during a tensile test, is taken as a measure of texture strengthening. In face-centred cubic structures, texture strengthening has been completely ignored on the basis that materials with R less than one are not amenable to this beneficiation. This study will review two aspects of texture which will lead to strengthening, first the thermal stability of the deformed microstructure, which is dependent on the stress axis, and second, the texture strengthening aspect of fee metals.A review of recovery and recrystallization in textured aluminum wires, copper and cupro-nickel sheet will be presented with the view of extending these concepts to the manufacture of heat-exchanger tubing. The superior creep properties of specially processed commercial products such as TD-Ni, TD-NiCr and MAR-M200 will be shown to be a manifestation of the same physical phenomena.
Keywords: Technology, Metallurgical sciences, Strengthening, Texture strengthening, Heat exchangers, Shear, Stress, Plastic flow, Yield strength, Alloys, Titanium alloys, Zirconium alloys, Copper sheet, Cupro-nickel sheet, Aluminum wire, Steel.
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Summary: This paper discusses the changing nature of reserve/consumption ratios, using data from Canadian operations and focus-sing particularly on copper.
Publication: CIM Bulletin
Author(s): F.-W. WELLMER
Keywords: Mineral economics, Reserves, Consumption, Copper deposits, Production, Lead, Zinc.
Issue: 831
Volume: 74
Year: 1981
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Summary: The recent development of the continuous casting process for steel has required basic understanding in a number of areas in the metallurgcal sciences. In some areas, information is still lacking. The success of the application of basic knowledge and research to the process is evidenced by the fact that a large percentage of the steel now produced in the world is produced by continuous casting.A number of areas in which metallurgical science has contributed and is currently contributing to...
Publication: CIM Bulletin
Author(s): F. WEINBERG
Keywords: Technology, Metallurgical sciences, Casting, Continuous casting, Steel, Heat transfer, Fluid flow, Solidification, Strength, Ductility.
Issue: 831
Volume: 74
Year: 1981
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Summary: In describing the alteration of porphyry systems, the term "secondary K-feldspar" appears to be an oversimplification. A better term would be "alkali feldspar" alteration, because in actual fact the replacement feldspars show gradational changes from an albite, which is important in some systems, to an alkali feldspar containing minor orthoclase molecule, to true orthoclase.There are several textural varieties of secondary alkali feldspar present in the porphyry systems...
Publication: CIM Bulletin
Author(s): CRAIG H. B. LEITCH
Keywords: Mineralogy, Feldspars, Alkali feldspars, Porphyry systems, Alteration, Mineralization, Exploration, Albite, Orthoclase.
Issue: 831
Volume: 74
Year: 1981
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Summary: The need to make repairs is seldom a major consideration in the design, fabrication and installation of major components of electrical generation plants. Repair welding, however, is a fact of life in the electrical generation industry, for restoration of degradation in service, from cavitation of hydraulic turbine runners, to corrosion and fatigue damage in pressure vessels. In making weld repairs to carbon and low-alloy steels, the largest source of trouble is hydrogen embrittlement and...
Publication: CIM Bulletin
Author(s): W.H.S. LAWSON, D. MILLS
Keywords: Technology, Metallurgical sciences, Welding, Repair welding, Power plants, Hardness
Issue: 831
Volume: 74
Year: 1981
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Summary: Nuclear power reactors using zirconium alloy pressure tubes generate electricity in several countries. Such reactors are particularly important in Ontario, where CANDUs generate about 30% of the total electricity produced in the Province. Starting with the commitment of NPD-2 in 1956, the pressure tubes of the first five CANDU reactors were made of cold-worked Zircaloy-2, an alloy of Zr and Sn. This alloy was developed by the US Navy, but the decision to use it in a cold-worked condition was...
Publication: CIM Bulletin
Author(s): C.E. ELLS, W. EVANS
Keywords: Technology, Metallurgical sciences, Pressure tubes, Reactors, CANDU reactor, Alloys, Zircaloy, Niobium.
Issue: 831
Volume: 74
Year: 1981
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Summary: Cryogenic engineering is concerned with components and machines which operate for long periods of time at temperatures within a few degrees of absolute zero. The absence of a ductile-brittle transition is thus the prime component of the specification for a suitable low-temperature alloy. The word "cryo" means "frost-forming", and this leads to the second component of the alloy specification, which is resistance to corrosion in humid atmospheres. Further, although most...
Publication: CIM Bulletin
Author(s): H.W. KING
Keywords: Technology, Metallurgical sciences, Stainless steels, Cryogenics, Phase equilibrium, Ferromagnetic transitions, Alloys, Magnetization, Steel.
Issue: 831
Volume: 74
Year: 1981
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Summary: Most unconformity-type uranium deposits in Saskatchewan occur within a few tens of metres above and/or below the basal unconformity of the 1.45-b.y. Athabasca Sandstone. Graphitic basement rocks coincident with post-Athabasca faulting or brecciation at or near the unconformity are important in localizing uranium deposits which form as tabular, ribbon-like bodies with grades averaging over 2 per cent uranium and containing up to 50,000 tonnes U3O8. Some of these deposits have similar contents...
Publication: CIM Bulletin
Author(s): L.A. CLARK, G.H.R. BURRILL
Keywords: Ore genesis, Uranium ore, Saskatchewan, Australia, Exploration, Jabiluka deposits, Ranger deposits, Rabbit Lake deposit, Midwest deposit, Key Lake deposit, Alligator Rivers deposits.
Issue: 831
Volume: 74
Year: 1981
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Summary: A semi-continuous belt of Aphebian magnesian extrusive and related subvolcank rocks has been delineated by the authors over a distance of 150 kilometres in the central La Ronge lithostructural domain in Saskatchewan. They range in composition from peridotite to basalt and attain true thicknesses of up to 800 metres. For the most part, they are confined to a basal position in the La Ronge/Wasekwan metavolcanic sequence, and appear to have been extruded onto sialic crust. However, at Lynn Lake,...
Publication: CIM Bulletin
Author(s): J.S. FOX, W.G.Q. JOHNSTON
Keywords: Volcanics, Magnesian volcanics, Waddy Lake, Reindeer Lake, Agassiz Mine, Exploration, Nickel exploration, Gold exploration, La Ronge area, Saskatchewan, Manitoba.
Issue: 831
Volume: 74
Year: 1981
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