Search Results for non-mechanical cleaning

Aluminum, a commonly used base material for brazing, can be easily fabricated by most manufacturing methods, such as machining, forming, and stamping. This article outlines non-heat-treatable wrought alloys typically used as base metals for the brazing process. It highlights chloride-active and fluoride-active types of fluxes that are used for torch, furnace, or dip brazing processes. The article explains the steps to be performed, including the designing of joints, preblaze cleaning, assembling, brazing techniques (dip brazing, furnace and torch brazing, fluxless vacuum brazing), flux removal techniques, and postbraze heat treatment processes. It concludes with information on the safety precautions to be followed during the brazing process.

Porcelain enamel is a fusion bonded glass coating that resists chemical and abrasive attack, provides thermal and electrical insulation, and improves aesthetic qualities. It is used on cast iron as well as steel and aluminum alloys. This article provides a review of the porcelain enameling process, the composition of frits, and the preparation of coating substrates. It also provides information on chemical, mechanical, and electrical properties and sheds light on process consistency and quality control.

Brazing technology is continually advancing for a variety of metals including aluminum and its alloys and nonmetals. This article discusses the key physical phenomena in aluminum brazing and the materials for aluminum brazing, including base metals, filler metals, brazing sheet, and brazing flux. It describes various aluminum brazing methods, such as furnace, vacuum, dip, and torch brazing. Friction, flow, induction, resistance, and diffusion brazing are some alternate brazing methods discussed. The article reviews the brazing of aluminum to ferrous alloys, aluminum to copper, and aluminum to other nonferrous metals. It also discusses post-braze processes in terms of post-braze heat treatment and finishing. The article concludes with information on the safety precautions considered in brazing aluminum alloys.

This article describes the high-temperature solid-state welding process used to join members of similar or dissimilar materials by three stages, namely, primary bonding, bond-surface extension, and elimination of the original joining surface. It lists the various advantages and disadvantages of the high-temperature solid-state welding process. The article discusses important process parameters for high-temperature solid-state welding, such as temperature, pressure, welding time, and welding atmosphere. It concludes with information on the application of the process in the fields of aerospace and nuclear engineering.

Cold pressure welding can be accomplished by deforming in a lap or butt configuration, drawing, extrusion, and rolling. This article provides a discussion on cold pressure lap welding, cold pressure butt welding and cold pressure welding in drawing process with illustrations. It provides information on the combinations of metals that can be successfully cold welded.

This article discusses the properties of aluminum surface and the applications of aluminum alloys. It explains the effects of trace elements on aluminum alloys. The article considers microstructural development of aluminum in terms of the surface and explains how it will impact corrosion resistance and surface treatment. It describes the thermodynamics of equilibrium oxidation processes and non-equilibrium corrosion processes. The article provides a discussion on aluminum oxidation under atmospheric and dynamic conditions. It presents the potential/pH (Pourbaix) diagram for aluminum under atmospheric and dynamic conditions. The article also explains the polarization effects during the formation of stable aluminum oxide under dynamic conditions. It concludes with information on the designation system for aluminum finishes.

This article focuses on the mineral and organic acid cleaning of iron and steel. It begins with a discussion on the application methods, process selection criteria, solution composition, equipment used, and control of process variables in mineral acid cleaning. The article then describes the advantages and disadvantages of organic acid cleaning. Applications, including boiler cleaning, stainless steel cleaning, and removal of iron- and copper-bearing deposits, are discussed. The article concludes with an overview of acid cleaning of nonferrous alloys.

This article reviews the steps involved in presurface-preparation inspection: substrate replacement; removal of weld spatter, rounding of sharp edges, and grinding of slivers/laminations; and removal of rust scale, grease, oil, and chemical (soluble salt) contamination. It focuses on surface preparation methods that range from simple solvent cleaning to hand and power tool cleaning, dry and wet abrasive blast cleaning, centrifugal wheel blast cleaning, chemical stripping, and waterjetting for the application of the coating system. In addition, the article provides a description of the Society for Protective Coatings' (SSPC) standards and NACE International standards as well as the International Organization for Standardization (ISO) standards and International Concrete Repair Institute (ICRI) guidelines for surface cleanliness.

A wide variety of stop-off technologies for heat treatment are used to selectively prevent the diffusion of carbon and/or nitrogen during atmosphere carburizing, carbonitriding, vacuum carburizing, and various forms of nitriding. In addition to selective stop-off, technologies are also available for scale prevention in open-fired furnaces. This article describes two stop-off technologies, mechanical masking and copper plating, along with stop-off paints/compounds. Prior to the application of stop-off paints, the part surface of the furnaces should be properly cleaned and dried. The article also describes the usage of stop-off paints in different heat treating processes, namely, carburizing and carbonitriding, deep carburizing, vacuum carburizing, nitriding and nitrocarburizing, and plasma nitriding. The article concludes by reviewing the application methods of stop-off paints: brushing, dipping, dispensing, spraying and stamping.

Wear is mechanically-induced surface damage that results in the progressive removal of material. Because different types of wear occur in machinery, many different types of wear tests have been developed to evaluate its effects on materials and surface treatments. This article provides an explanation on mechanisms, forms (sliding, impact, and rolling) and the causes of wear. It describes the wear measuring methods, including the mass loss method, wear width method, and scar depth method. The units used to report wear vary with type of wear and with the purpose for which the data are to be used. Listing the considerations of tribosystem analysis, the article provides information on selection of ASTM wear test methods grouped by wear type. The article concludes by tabulating the testing geometries and parameters that are commonly controlled and reported when conducting wear tests.

This article provides a brief review of the classification and characteristics of cast irons. It describes the processes used to clean iron castings, including mechanical cleaning and finishing and nonmechanical cleaning. The article discusses surface treatments used to extend casting life when resistance to corrosion, wear, and erosion is required. The common methods include electroplating, electroless plating, hardfacing, weld cladding, surface hardening, porcelain enameling, and organic coatings.

Mechanical plating is a method for coating ferrous metals, copper alloys, lead, stainless steel, and certain types of castings by tumbling the parts in a mixture of glass beads, metallic dust or powder, promoter or accelerator chemicals, and water. It offers a straightforward alternative method for achieving desired mechanical and galvanic properties with an extremely low risk of hydrogen embrittlement. This article provides a detailed description of the equipment, process steps, process capabilities, applicable parts, specific characteristics, advantages, limitations, post treatments, and waste treatment of mechanical plating.

Although aluminum alloys are inherently corrosion resistant, there are many operating environments where they require additional protection. This article describes the conditions under which aluminum is prone to corrode and explains how to prevent it through the addition of conversion coatings and paints. It addresses some of the more common corrosion mechanisms, including corrosion driven by pH extremes, pitting corrosion, crevice corrosion, galvanic corrosion, and filiform corrosion. The article also describes in-plant as well as field application procedures for cleaning and coating, and discusses the advantages and limitations of the various materials and chemicals used.

Chemical-mechanical planarization (CMP) of metals is described as mechanically accelerated corrosion, erosion corrosion, or metallic corrosion enhanced by wear. This article reviews the history, process, chemistry, electrochemistry, and defect issues for CMP. It provides an overview of CMP through a schematic illustration of CMP process equipment. The applications of CMP to tungsten and copper alloys are of prime interest in the semiconductor industry. The article discusses copper CMP and tungsten CMP in detail and analyzes polishing mechanism during CMP by application of direct current potentiodynamic polarization and alternating current impedance measurements. It concludes with information on chemically induced defects such as pitting corrosion, galvanic corrosion, and chemical etching.

This article focuses on the aspects associated with inspection related to pressure vessels and pipework. These aspects include inspection policy, inspection planning and procedures, inspection strategy, inspection methodology, preparation for inspection, invasive inspection, internal visual inspection, and non-invasive inspection. Inspection execution, risk-based inspection, competence assurance of inspection personnel, inspection coverage, inspection periodicity, inspection anomaly criteria, assessment of fitness, and reporting requirements, are also discussed. The article addresses the data acquisition, reporting and trending, and review and audit for the inspection. It reviews inspection techniques, including visual inspection, ultrasonic inspection, and radiographic inspection.

This article focuses on the various types of corrosion-related failure mechanisms and their effects on passive electrical components. The types include halide-induced corrosion, organic-acid-induced corrosion, electrochemical metal migration, silver tarnish, fretting, and metal whiskers. The passive electrical components include resistors, capacitors, wound components, sensors, transducers, relays, switches, connectors, printed circuit boards, and hardware.

This article describes the influences of the operational environments of U.S. Navy aircraft during corrosion-control process. The most widely used materials in airframe structures and components, such as aluminum, steel, titanium, and magnesium alloy systems, are reviewed. The article provides information on the inspections steps, corrosion-control issues, and corrosion-prevention strategies for naval aircraft. It contains a table that lists typical locations of corrosion on the aircraft. The article also provides examples of aircraft corrosion damage.

This article discusses the procedures used for pickling nickel and nickel alloys. Nickel alloys can be divided into four groups: high-nickel alloys, nickel-copper alloys, nickel-chromium alloys, and nickel-iron-chromium alloys. Alloys within each composition group that has similar surface conditions are pickled in the same solutions using the same procedures. The article discusses three different surface conditions for pickling these nickel alloys: bright annealed white surface requiring removal of tarnish by flash pickling; bright annealed oxidized surface requiring removal of a layer of reduced oxide, sometimes followed by a flash pickle to brighten; and black or dark-colored surface requiring removal of adherent oxide film or scale. The article also reviews specialized pickling operations of nickel alloys and various cleaning and finishing operations, including grinding, polishing, buffing, brushing, and blasting.

This article presumes the reader has a basic understanding of the operation and principles of scanning electron microscopy (SEM). The emphasis of this article is specifically on the application of SEM to the study of metallic and nonmetallic fracture surfaces, where the typical objectives of SEM examination of a fracture surface may include the following: identification of characteristic fracture features to aid in identifying fracture mechanism(s); characterization of material anomalies that may have influenced the fracture; qualitative or semiquantitative chemical analysis of component material(s); and qualitative or semiquantitative analysis of deposits or corrosion products on or near fracture surfaces.

Environmental effects of ground and flight environments, including temperature extremes, damage by chemical fluids, moisture, and so forth, affect the durability of polymer-matrix composites. This article provides information on corrosion control methods in aircraft structures. It discusses the design considerations for sealants in joints. The article describes the common methods to seal aircraft structures: fay surface, fillet, butt joint, channel, brush, and form-in-place seals. It discusses the surface preparation and application method of primer and topcoat systems. Primer and paint application equipment as well as sealant application equipment are reviewed.