Search Results for thermostat metal

Electrical resistance alloys used to control or regulate electrical properties are called resistance alloys, and those used to generate heat are referred to as heating alloys. This article covers both alloy types, describing the construction and use of resistors as well as heating elements. It also discusses soldering and joining methods, sensitivity and stability factors, and various design coefficients. In addition, it provides a detailed account of the properties and applications of thermostat metals and discusses the design of resistance heaters and their operating ranges.

This article contains a table that lists the electrical conductivity and resistivity of selected metals, alloys, and materials at ambient temperature. These include aluminum and aluminum alloys; copper and copper alloys; electrical heating alloys; instrument and control alloys; relay steels and alloys; thermostat metals; electrical contact materials; and magnetically soft materials.

Electrical resistance alloys include those types used in instruments, control equipment, heating elements, and devices that convert heat generated to mechanical energy. This article discusses the basic classification of electrical resistance alloys (resistance alloys, heating alloys, and thermostat metals), their subtypes, properties, service life, and operating temperatures. It describes the designing and fabrication of open resistance and sheathed heaters. The article contains a collection of tables and graphs that provide information on the mechanical properties, chemical composition, temperature coefficient of resistance, furnace operating temperatures, length and spacing of loops, ribbon size, and electrical capacity of heating elements.

Advances in vehicle design and technology require engine coolant technology to minimize the degradation of nonmetals and prevent the corrosion of the metals in the cooling system. This article provides a detailed discussion on the functions, operation, materials, and major components of the cooling system. It discusses various forms of corrosion that occur in cooling systems, including uniform corrosion, galvanic corrosion, crevice corrosion, pitting corrosion, intergranular corrosion, erosion corrosion, and cavitation corrosion. The article presents information on engine coolant base components and inhibitors used for corrosion prevention. It reviews the coolant performance tests recommended by ASTM, SAE, and vehicle manufacturers. The article concludes with a description on the difference between light-duty automotive and heavy-duty diesel engine coolants.

This article describes the principal cladding processes and methods for calculating properties of clad metals. It reviews the designing processes of clad metals to achieve specific requirements. The article discusses six categories of clad metal systems designed for corrosion control: noble metal clad systems, corrosion barrier systems, sacrificial metal systems, transition metal systems, complex multilayer systems, and clad diffusion alloys.

Solvent cleaning is a surface preparation process that can be accomplished in room temperature baths (cold cleaning ) or by condensing vapors of a solvent on a workpiece (vapor degreasing). This article provides a detailed discussion on solvents, equipment, process limitations and applications, and safety and health hazards of cold cleaning and vapor degreasing. It also includes information on control of contamination, conservation and recovery of solvent, and disposal of solvent wastes.

Roll welding (ROW) is a process in which two or more sheets or plates are stacked together and then passed through the rolls until sufficient deformation has occurred to produce solid-state welds. This article begins with a process description of two modes of roll welding, including pack rolling. It describes a patented roll welding process for fabrication of heat exchangers. The article presents a table showing the typical properties of common roll welded clad laminates. The relative weldability of selected dissimilar metals and alloys roll welded into clad-laminate form are also tabulated. The article concludes with information on cladding of metals by strip roll welding.

Low-expansion alloys are characterized by their dimensional stability, suiting them for applications such as geodetic tape, bimetal strip, glass-to-metal seals, and electronic components. This article describes the composition of such alloys along with related properties and behaviors. It explains how humidity and other factors, such as heat treating and cold drawing, influence thermal expansion rates. It also provides machining information on some of the more common low-expansion alloys, and reviews special alloy types including iron-cobalt-chromium alloys, hardenable alloys, and high-strength controlled-expansion alloys.

Low-expansion alloys are materials with dimensions that do not change appreciably with temperature. Alloys included in this category are various binary iron-nickel alloys and several ternary alloys of iron combined with nickel-chromium, nickel-cobalt, or cobalt-chromium alloying. Low-expansion alloys are used in various applications such as rods and tapes for geodetic surveying, moving parts that require control of expansion (such as pistons for some internal-combustion engines), bimetal strip, components for electronic devices etc. This article discusses the properties, composition, and applications of iron-nickel low-expansion alloys (Invar), as well as other special alloys, including iron-nickel-chromium alloys, iron-nickel-cobalt alloys, iron-cobalt-chromium alloys, and high-strength, controlled-expansion alloys. It covers the factors affecting coefficient of thermal expansion of iron-nickel alloys, including heat treatment and cold drawing. Magnetic, physical, thermal, electrical and mechanical properties of iron-nickel alloys are also covered.

This article describes two methods based on rolling of sheet. The first is roll welding, where two or more sheets or plates are stacked together and then passed through rolls until sufficient deformation has occurred to produce solid-state welds. The other is laser roll welding, which is a hybrid process based on a thin-melting interface for a lap joint of dissimilar-metal sheets using a roller and one-sided laser heating. The article discusses the types, advantages, and applications of roll welding and laser roll welding. It also provides a detailed discussion on the laser roll welding of dissimilar metals.

This article focuses on the electroless gold plating technique, describing the advantages and limitations, applications, and properties of plated deposits. It also reviews process variables of the technique, including gold concentration, reducing agent, agitation, and contaminants.

Fabrication of high-density heat exchangers, which have a large heat transfer area and a compact size, is best accomplished by brazing where the brazing filler metal is clad to the materials to be brazed. This article focuses on the brazing procedures involved in the fabrication of high-density heat exchangers. The brazing procedures include base metal and brazing filler metal selection; fabrication of clad brazing materials; and stamping, cleaning, and assembling of cladded parts. The article concludes with an examination of brazing parameters.

Electrical contacts are metal devices that make and break electrical circuits. This article provides information on materials selection criteria and failure modes of make-break contacts. It describes the property requirements for make-break arcing contacts, namely, electrical conductivity, mechanical properties, chemical properties, fabrication properties, and thermal properties. The article presents a brief note on brush contact materials and their interdependence factors for sliding contacts. It also describes the type of commercial contact materials for electrical contacts, namely, copper metals, silver metals, gold metals, metals of the platinum group, precious metal overlays, tungsten and molybdenum, aluminum, and composite materials. Finally, the article provides information on composite manufacturing methods, and tabulates the physical, and mechanical properties of electrical contact materials, including copper, silver, gold, platinum, palladium, and composites.

The term shape memory alloys (SMAs) refers to the group of metallic materials that demonstrate the ability to return to some previously defined shape or size when subjected to the appropriate thermal procedure. Materials that exhibit shape memory only upon heating are referred to as having a one-way shape memory. Some materials also undergo a change in shape upon recooling. These materials have a two-way shape memory. This article discusses the general characteristics of SMAs by using typical transformation versus temperature curve. It describes the processing, applications and properties (mechanical and physical) of commercial SMA alloys, namely nickel-titanium alloys and copper-base alloys.

Electrical contacts are made of elemental metals, composites, or alloys that are made by the melt-cast method or manufactured by powder metallurgy (PM) processes. PM facilitates combinations of metals that ordinarily cannot be achieved by alloying. This article describes the processing, properties, and performance of electrical contacts based on PM or hybrid composite technologies with refractory metals and compounds. These metals and compounds include tungsten, molybdenum, carbide-based composites, and silver-base composites. The article explains composite manufacturing methods, namely, PM methods, internal oxidation, and hybrid consolidation. The availability of the refractory metals and compounds in various product forms are also reviewed.

Hard chromium plating is produced by electrodeposition from a solution containing chromic acid and a catalytic anion in proper proportion. This article presents the major uses of hard chromium plating, and focuses on the selection factors, plating solutions, solution and process control, equipment, surface preparation, and crack patterns and other characteristics of hard chromium plating. It offers recommendations for the design and use of plating racks, describes the problems encountered in hard chromium plating, and their corrective procedures. The article provides information on the removal of chromium plate from coated metals, recovery and disposal of wastes, and stopoff media for selective plating.

Electrogravimetry is a method used to separate and quantify ions of a substance, usually a metal. Quantification of these ions primarily depends on the rate of movement of charged species (ions) in an electric field. This article details the various types of electrometric titrations, namely, conductometric titration, oscillometric (high frequency) titration, potentiometric titration, amperometric titration, biamperometric titration, bipotentiometric titration, and coulometric titration. It also provides a brief outline of the applications of electrometric titrations.

This article provides an overview of the fundamentals of tribology. It describes the advantages, disadvantages, and applications of the pin-on-disk method, which is the most commonly used configuration for testing biomaterials and for the reproducible measurement of friction and wear. The article illustrates a practical tribocorrosion setup that allows a user to perform wear tests in corrosive environments under well-defined electrochemical conditions and at controlled temperature. It explains the effect of changes in electrical contact resistance on tribological mode. The article discusses various in vivo environmental conditions in tribological tests. Some typical examples of biomaterials testing are also provided.

This article discusses the definitions, classifications, structural features, vapor pressure values, corrosion inhibition mechanisms, and methods of evaluation of vapor-phase-corrosion inhibitors or volatile corrosion inhibitors (VCIs). Practical methods of using VCIs for corrosion protection of aluminum, ferrous, and nonferrous alloys are discussed with specific examples. The article contains tables that summarize the applications of different VCIs used for protecting ferrous metals, copper and its alloys, and silver.

This article provides information on metals that can be cast in permanent molds. It describes the advantages, disadvantages, applications, and design of permanent castings. Following a discussion on the factors considered in mold design and material selection, the article details the application of mold coatings and examines the effects of major processing variables on mold life. The variables that determine mold temperature and measures for controlling it are reviewed, and the effects of short-term and long-term variables on the dimensional accuracy of permanent mold castings are explained. The article concludes with a discussion on the factors influencing the surface finish on permanent mold castings.