Search Results for casting cleaning

Coating of cast irons is done to improve appearance and resistance to degradation due to corrosion, erosion, and wear. This article describes inorganic coating methods commonly applied to cast irons. The coating methods include plating, hot dip coating, conversion coating, diffusion coating, cladding, porcelain enameling, and thermal spray. Organic coatings have a wide variety of properties, but their primary use is for corrosion resistance combined with a pleasing colored appearance. The article discusses the various types of organic coatings applied to cast irons. Practically any degree of smoothness or roughness and requirement for color and gloss can be filled by organic coatings. The article describes abrasive blast cleaning, abrasive waterjet cleaning and finishing, vibratory finishing, barrel finishing, and shot peening for processing iron castings.

Molten salt baths are anhydrous, fused chemical baths used at elevated temperatures for a variety of industrial cleaning applications. This article discusses their applications in paint stripping, polymer removal, casting cleaning, glass removal, and plasma/flame spray removal. It provides an overview of the basic design and safety considerations of the salt bath equipment and describes the environmental impact of molten salt bath cleaning.

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.

Babbitting is a process by which relatively soft metals are bonded chemically or mechanically to a stronger shell or stiffener which supports the weight and torsion of a rotating, oscillating, or sliding shaft. This article focuses on workpiece preparation and babbitting methods. Prior to casting, the workpiece must be scrupulously prepared by various cleaning, fluxing, and tinning steps. Babbitting of bearing shells can be accomplished by three methods, namely, static babbitting, centrifugal casting, and metal spray babbitting.

After solidification and cooling, further processing and finishing of the castings are required. This article describes the general operations of shakeout, grinding, cleaning, and inspection of castings, with particular emphasis on automation technology. It illustrates the vertical core knockout machine and the A-frame core knockout machine and lists the advantages and disadvantages of these machines. The article describes the general factors in automated or manual gate removal process. It concludes with discussion on the various types of inspection, such as the liquid penetrant inspection, pressure testing, radiographic inspection, magnetic particle inspection, and ultrasonic inspection.

Zinc and zinc alloys require surface engineering prior to coating or use to improve adhesion and corrosion resistance. Die-cast zinc parts, in addition, must be trimmed and finished to remove flash and parting lines. This article covers zinc cleaning procedures as well as coating and finishing processes. It explains how to remove parting lines and presents several mechanical finishing methods, including surface polishing, brushing, controlled shot peening, and buffing. It also provides information on solvent cleaning, emulsion cleaning, aqueous detergent or alkaline cleaning), electrocleaning, acid dipping, and zinc conversion coating treatments.

Aluminum casting in steel and iron permanent molds is used widely throughout industry, and the vast majority of permanent mold castings are made of aluminum and its alloys. There are several methods used to cast aluminum in permanent molds. This article focuses on permanent mold casting with molten aluminum fed by gravity, low pressure, vacuum and centrifugal pressure, and squeeze casting. It discusses the major variables that affect the life of permanent molds, including pouring temperature, casting shape, cooling methods, heating cycles, storage, and cleaning. The article reviews the basic components of mold coatings: refractory fillers, binder, and carrier. Casting defects and suggested corrective actions for permanent mold casting are summarized in a table. The article concludes with a discussion on thin-wall permanent-mold castings.

Aluminum fluxing is a step in obtaining clean molten metal by preventing excessive oxide formation, removing nonmetallic inclusions from the melt, and preventing and/or removing oxide buildup on furnace walls. This article discusses the solid fluxes and gas fluxes used in foundries. It reviews the classification of solid fluxes depending on their use and function at the foundry operation. These include cover fluxes, drossing fluxes, cleaning fluxes, and furnace wall cleaner fluxes. The article also examines the operational practices and applications of the flux injection in the foundries. It describes the applications of the aluminum fluxing such as crucible furnaces, transfer ladles, reverberatory furnaces, and holding/casting furnaces.

Materials of construction for equipment and piping in pharmaceutical processing plants must be resistant to corrosion from the high-purity water, the buffer solutions used in preparation of the products, and the cleaning solutions used to maintain the purity of the product. The primary water used in pharmaceutical production is water for injection (WFI). This article presents the steps for preparing WFI and discusses the effect of chlorides on stainless steel. It provides information on the passive layer of stainless steels and chromium-containing nickel alloys. The article provides information on the surface finish of pharmaceutical equipment. It discusses the classification of rouge and the characteristics of cast type 316L stainless steel. The article also explains how and when to perform cleaning and repassivation process on classes of rouge.

There are a wide variety of furnace types and designs for melting aluminum. This article discusses the various types of furnaces, including gas reverberatory furnaces, crucible furnaces, and induction melting furnaces. It describes the classification of solid fluxes: cover fluxes, drossing fluxes, cleaning fluxes, and furnace wall cleaner fluxes. The article reviews the basic considerations in proper flux selection and fluxing practices. It explains the basic principles of degassing and discusses the degassing of wrought aluminum alloys. The article describes filtration in wrought aluminum production and in shape casting. It also reviews grain refinement in aluminum-silicon casting alloys, aluminum-silicon-copper casting alloys, aluminum-copper casting alloys, aluminum-zinc-magnesium casting alloys, and aluminum-magnesium casting alloys. The article concludes with a discussion on aluminum-silicon modification.

Cast irons and carbon steels are brazeable materials, although the brazeability of cast iron is lower than that of carbon steel. The article provides a detailed discussion on the brazeability of different types of cast iron (malleable iron, ductile iron, and gray iron), carbon steels, and dissimilar metals. It describes the factors considered in the selection of filler-metal for cast iron and carbon steel brazing, such as temperature and environment, brazed joint design, heat source, and heat-treatment requirements. The article also discusses the basic considerations in cleaning and fixturing procedures, filler metal and flux/atmosphere feeding procedures, and the heating methods of cast iron and carbon steel brazing.

Investment casting, in which molten metal is poured into hot molds, allows for the production of aluminum parts with extremely thin sections, knife edges and sharp detail. This article describes the various steps in the investment casting process, including patternmaking and dimensioning, the design and manufacture of shell molds, melting and casting methods, and postcasting operations such as knockout, core removal, and cleaning. It also addresses a wide range of design considerations, discusses casting defects, and provides several design examples.

This article discusses the sequence of operations for producing a foam pattern for casting. It provides information on expandable polystyrene, the most preferred material for manufacturing lost foam patterns. The article then describes the major functions of pattern molding and assembly. The types and application methods of various lost foam coatings are explained. The article also describes the investment of the foam pattern in a sand system. It concludes with a discussion on the advantages of lost foam casting and information on the formation and control of folds.

High-pressure die casting is a fast method for the net shape manufacturing of parts from nonferrous alloys. This article reviews the automation technologies for the different stages or steps of the process. These steps include liquid metal pouring, injection, solidification, die open, part extraction, die lubrication, insert loading, and die close. Some manual aspects of the operations, together with automation options, are discussed. The article describes finishing steps, such as finish trimming, detailed deflashing, shot blast cleaning, and quality checks. Automation of the postcasting process is also discussed.

Precipitation hardening is a hardening mechanism found in various steels and alloy systems, such as nickel-, cobalt-, titanium-, copper-, and iron-base alloys. This article provides a brief description of precipitation hardening process, furnace equipment, surface-related problems, and protective atmospheres used in heat treatment of iron-base precipitation-hardenable (PH) superalloys. It focuses on various factors to be considered in heat treating of PH stainless steels: cleaning prior to heat treatment, furnace atmospheres, time-temperature cycles, variations in cycles, and scale removal after heat treatment. The article describes the mechanical properties, solution treatment, and aging treatment for many martensitic PH alloys, including: Alloy 17-4 PH, Alloy 13-8 Mo, Alloy 15-5 PH, Custom 450, and Custom 455; as well as semiaustenitic PH stainless steels such as Alloy 17-7 PH, Alloy PH 15-7 Mo, AM-350, Pyromet 350, AM-355, and Pyromet 355; austenitic PH stainless steel, A-286; cast PH stainless steels; and iron-nickel PH superalloys.

Martensitic stainless steels are the least corrosion-resistant of all stainless alloys. The traditional martensitic stainless steels are iron/chromium/carbon alloys, sometimes with a small amount of nickel and/or molybdenum. This article provides an overview on the influences of the various possible alloying elements on the key properties of martensitic stainless steels. It describes the various preparation processes, namely, atmosphere selection, cleaning, and preheating, prior to heat treatment for these steels. Common heat treatment methods include annealing, hardening, tempering, and stress relieving. The article lists the compositions of casting alloys and also describes the effect of tempering temperature on the hardness, strength, ductility, and toughness properties of the alloys.

Wrought copper and copper alloys are produced in various mill-product forms for a variety of applications due to their high electrical conductivity, corrosion resistance, ease of fabrication, and good heat-transfer properties. This article describes the manufacturing processes used to produce wrought copper and copper alloys in the form of sheet and strip products, tubular products, and wire and cable. Common processes include melting, casting, hot and cold rolling, milling or scalping, annealing, cleaning, slitting, cutting, and leveling. In addition, the article discusses stress-relaxation characteristics of copper alloys.

This article discusses surface engineering of nonferrous metals including aluminum and aluminum alloys, copper and copper alloys, magnesium alloys, nickel and nickel alloys, titanium and titanium alloys, zirconium and hafnium, zinc alloys, and refractory metals and alloys. It describes various techniques to improve functional surface properties and enhance the appearance of product forms. The article discusses various cleaning and finishing techniques such as abrasive blast cleaning, polishing and buffing, barrel burnishing, chemical cleaning, pickling, etching and bright dipping, electrochemical cleaning, mechanical cleaning, and mass finishing. It also examines coating processes such as plating, anodizing, chemical conversion coating, and thermal spray, and concludes with a discussion on oxidation-resistant coatings for refractory metals.

Mechanical cleaning systems are used to remove contaminants of work surface by propelling abrasive materials through any of these three principal methods: airless centrifugal blast blade- or vane-type wheels; compressed air, direct-pressure dry blast nozzle systems; or compressed-air, indirect-suction (induction) wet or dry blast nozzle systems. This article focuses on the abrasive media, equipment, applications, and limitations of dry and wet blast cleaning. It discusses the health and safety precautions to be taken during mechanical cleaning.