Search Results for compressed air blast nozzle systems

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.

Thermal spray coating involves certain precoating operations, such as cleaning, surface preparation, and masking, that are critical to the overall quality of the coating system. In addition to these, certain other elements are considered prior to the coating, namely, customer requirements, coating function, part geometry, substrate metallurgy, structure, and thermal history. This article provides a detailed account of the various processes of surface preparation, namely, cleaning, roughening, dry abrasive grit blasting, and machining and macro roughening processes. It outlines the masking and fixturing techniques and stripping of coatings.

This article provides information on the factors influencing the selection of the proper corrosion-resistant coating system. It focuses on the proper execution of surface preparation and the available surface preparation methods. The preparation process includes the removal of visible contaminants, removal of invisible contaminants, and roughening of the surface. Solvent or chemical washing, steam cleaning, hand tool cleaning, power tool cleaning, water blasting, and abrasive blast cleaning, are some preparation methods discussed. The article describes the most common application techniques of coating as well as the equipment used. An overview of some of the most common coating inspection points and inspection equipment is also provided.

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.

Shot peening is a method of cold working in which compressive stresses are induced in the exposed surface layers of metallic parts by the impingement of a stream of shot, directed at the metal surface at high velocity under controlled conditions. This article focuses on the major variables, applications, and limitations of shot peening and provides information on peening action, surface coverage, and peening intensity. It discusses the equipment used for shot recycling and shot propelling as well as the types and sizes of media used for peening. The article describes the problems in shot peening of production parts. It concludes with information on the SAE standard J442 that describes the test strips, strip holder, and gage used in measuring shot peening intensity.

Shot peen forming is a manufacturing process in which local compressive residual stresses form thin sheet metals and structural components in one or more dimensions. This article discusses the principle of the process with an emphasis on fundamental mechanisms. It presents the basic considerations in the simulation of shot peen forming and provides information on single impact and multiple-impact peening simulations. The article describes the equipment and tooling used in the process. It also analyzes the influence of process parameters on shot peen forming and illustrates possible shapes and contours, which are producible by shot peen forming. The article concludes with a table that presents typical peen forming applications in the aircraft and aerospace industries.

This article begins with a description of the advantages and disadvantages of thermal spraying. It provides a discussion on the importance of substrate processing prior to coating and the role of undercutting in repair. The article reviews the steps for substrate preparation, namely, cleaning, roughening, masking, and preheating. Information on the equipment and process variables of dry abrasive grit blasting are also provided. The article describes the roles of spray stream and the spray pattern for all thermal spray processes. It discusses the defects arising from poor temperature control and from the variables influencing the manipulation of the spray torch. The article concludes with helpful information on calculating the process efficiency of thermal spraying.

This article provides an insight into the cost estimation of painting projects for both contractors and others. The cost estimating methods include benchmarking, unit price estimating, developed pricing, market pricing, and critical path scheduling. The first step in developing an accurate estimate for an industrial painting contract is determining the scope of work. The article describes the method of calculating quantities of materials and labor, surface area takeoff, and equipment costs. It concludes by listing the forgotten costs and presenting information on coating condition assessment and determining selling cost.

Ceramic coatings are applied to metals to protect them against oxidation and corrosion at room temperature and at elevated temperatures. This article provides a detailed account of the factors to be considered when selecting a ceramic coating and describes the characteristics of various coating materials, namely, silicate glasses, oxides, carbides, silicides, and cermets. It reviews ceramic coating methods: brushing, spraying, dipping, flow coating, combustion flame spraying, plasma-arc flame spraying, detonation gun spraying, pack cementation, fluidized-bed deposition, vapor streaming, troweling, and electrophoresis. The article also includes information on the evaluation of the quality of ceramic coatings.

The process of transferring coating materials from the container to the surface to be coated can be accomplished in a number of ways. This article describes seven methods of coating application: brushes, rollers, and daubers; conventional air spray; high-volume low-pressure spray; airless spray; air-assisted airless spray; plural-component spray; and electrostatic spray. Factors to be considered when deciding on an application method include the size and configuration of the surfaces to be coated, the type of coating being applied, environmental regulations/restrictions, the proximity to other operations or personnel, and the recommendations of the coating manufacturer.

In high-iron-tonnage operations, the cupola remains the most efficient source of continuous high volumes of iron needed to satisfy high production foundries or the multiple casting machines of centrifugal pipe producers. This article explores successful improvement technologies in cupola equipment, including preheated air blast, recuperative hot blast systems, and duplex electric holders. It discusses the shell, intermittent or continuous tapping, tuyere and blower systems, refractory lining, water-cooled cupolas, emission-control systems, and storage and handling of the charge materials. The article provides a discussion on the control tests for cupola, including the chill test and mechanical test. It concludes with information on specialized cupolas such as the cokeless cupola and the plasma-fired cupola.

This article addresses the important variables in erosion, such as particle impact velocity; particle impact angle; particle size, shape, and material; and ambient temperature. It describes four erosion test methods: the gas-blast method, a method using a centrifugal accelerator test rig, the wind-tunnel test, and the whirling arm test. The article also details the various test methods used to measure impact velocity of particle and data analysis and interpretation of these four methods.

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.

Functional fusion-bonded epoxy (FBE) coatings are used as external pipe coatings, base layer for three-layer pipe-coating systems, internal pipe linings, and corrosion coatings for concrete reinforcing steel (rebar). This article provides information on the chemistries of FBE, and discusses the application procedures for internal and external FBE pipe coating. The procedures involve pipe inspection, surface preparation, heating, powder application, curing, cooling, coating inspection, and repairing. It describes the problems and solutions for FBE external pipe coatings, girth weld FBE application, FBE custom coatings, internal FBE pipe linings, and FBE rebar coatings.

Painting is a generic term for the application of a thin organic coating to the surface of a material for decorative, protective, or functional purposes. This article provides a detailed account of the types and selection factors of paints and the various application methods, including conventional air atomized, airless, and electrostatic spray; roller coating; dip coating; flow coating; curtain coating; tumble coating; electrocoating; and powder coating. Surface preparation methods and prepaint treatments for coating systems are also discussed. The article includes information on quality control procedures, causes of paint film defects, cost calculation, and safety and environmental precautions. The composition and characteristics of organic coatings, coating system selection factors, the types of paints for structural steel, and the applications of paint on structural steel are also reviewed.

Laser has found its applications in cutting, drilling, and shock-peening operations of manufacturing industry because of its accurate, safe, and rapid cutting property. This article provides an account on the fundamental principles of laser cutting (thermal), drilling, and shock-peening processes of which emphasis is placed on thermal laser cutting. It details the principal set-up parameters, such as the laser beam output, nozzle design, focusing optic position and characteristics, assist gases, surface conditions, and cutting speed. A discussion on the types of gas, supply system, purity level, and flow rates of lasing and assist gases is also provided. The article also describes the metallurgies and other key material considerations that impact laser-cutting performances and includes examples of laser cutting of nonmetal materials.

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.

Intensive quenching (IQ) is an alternative method of hardening steel parts. Two types of IQ methods are used in heat treating practice: IQ-2 and IQ-3. IQ-2 is implemented in IQ water tanks, which are usually used for batch quenching of steel parts. IQ-3 is conducted in single-part processing using high-velocity water flow IQ units. This article presents a detailed description of IQ technology, related equipment, and IQ applications. A review of intensive quench system design and processing is provided, including numerical design criteria, steel selection, quenchants, properties (especially optimal residual stress profiles). Several specific applications of intensive quenching are also provided.

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.

This article describes the technology of thermal spraying with regard to tribological applications. It introduces the basics of tribology and presents the fundamentals of thermal spraying and the relevant process variants and suitable materials. Specific application areas are described regarding the different forms of elementary movement in the corresponding tribological system. The article provides an overview of thermal spray coatings and possible uses for friction and wear control, besides operating as corrosion protection and a thermal barrier. The article provides examples that illustrate how tribological performance can be improved.