Search Results for surface quality

The inspection of castings normally involves checking for shape and dimensions, coupled with aided and unaided visual inspection for external discontinuities and surface quality. This chapter discusses methods for determining surface quality, internal discontinuities, and dimensional inspection. Casting defects including porosity, oxide films, inclusions, hot tears, metal penetration, and surface defects are reviewed. Liquid penetrant inspection, magnetic particle inspection, eddy current inspection, radiographic inspection, ultrasonic inspection, and leak testing for castings are discussed. The chapter provides information on the procedures involved in the inspection of castings that are limited to visual and dimensional inspections, weight testing, and hardness testing. It also discusses the use of computer equipment in foundry inspection operations.

Separation of billets by shearing avoids material loss and is considerably faster than sawing or cutting. This chapter discusses the billet shearing process, the characteristics of sheared surfaces, and the effect of various operating parameters on surface quality. It also includes formulas for calculating shearing force, work, and power and describes various ways to increase production rates.

This chapter discusses the various methods used to join titanium alloy assemblies, focusing on welding processes and procedures. It explains how welding alters the structure and properties of titanium and how it is influenced by composition, surface qualities, and other factors. It describes several welding processes, including arc welding, resistance welding, and friction stir welding, and addresses related issues such as welding defects, quality control, and stress relieving. The chapter also covers mechanical fastening techniques along with adhesive bonding and brazing.

This chapter discusses the scope of research and development in aluminum extrusion technology. Research in the key technology areas of friction, thermodynamics, and die wear are discussed. The chapter also highlights future developments in extrusion technology.

This chapter provides a summary of ongoing efforts to improve quality and productivity in the aluminum extrusion industry. It assesses advancements in several areas including extrusion presses and auxiliary equipment, tool and die technology, billet casting, extrusion thermodynamics and tribology, and process control.

This chapter describes the classification of steels and the various compositional categories of commercial steel products. It explains how different alloying elements affect the properties of carbon and low-alloys steels and discusses strength, toughness, and corrosion resistance and how to improve them.

In this chapter, process control of each operational stage is discussed, with a detailed process-control flow diagram to provide a better understanding and to create a process-control document of each operational process stage. This chapter also presents fundamental ideas of a complete process- and quality-control framework system of an aluminum extrusion plant, starting from alloy and billet making to the final heat treatment process parameters required to bring the extrusion to the final alloy and temper designation to meet product requirements.

Stop-off coatings prevent nitriding of selected areas on components. This chapter discusses the processes, advantages, and disadvantages of stop-off techniques for gas nitriding, salt bath nitriding, and ion nitriding.

This chapter familiarizes readers with the design, configuration, and function of tooling and dies used to extrude aluminum alloys. It discuses basic design considerations, including the geometry, location, and orientation of die openings; allowances for thermal shrinkage, stretching, and deflection; and the length and profile of bearing surfaces. It outlines the steps and processes involved in die making, describes the selection and treatment of die materials, and examines the factors that influence friction and wear. It also discusses the general procedures for on-site die correction.

This chapter discusses many aspects of extrusion die and tooling, including the terminology and function of extrusion die and tooling, the types of dies, the fundamentals of die design, manufacturing, correction, material, and the surface treatments of die bearings and tribology in extrusion dies. It then presents the fundamentals and function of finite-element modeling simulation. The chapter describes the role of tribology and thermodynamics in the die bearing to control the flow and dimensional stability of extrusion exiting the die.

This chapter discusses how aluminum and other alloying constituents are added to prepare a furnace charge for the melting process, and how it is cast into billets of various aluminum alloys. Fundamental aspects of billet casting are covered to give an overview of the casting process. The melting practice is discussed, as well as grain refining and degassing. Charge material, grain refining, degassing, filtration of melt, casting systems, and casting variables are discussed. The chapter concludes with a discussion of casting defects.

This chapter provides an overview of the rolling and finishing processes required to create a sheet, plate, or foil product from a direct chill (DC) cast ingot. The flow paths, equipment, and operations are described with a view to the basic evolution of the microstructure, surface characteristics, and dimensions.

This chapter discusses the extrusion technology of soft- and medium-strength aluminum alloys. The relative extrudability ratings of some soft- and medium-grade alloys are given. The chapter presents useful extrusion parameters and their relationships associated with day-to-day production practices in the aluminum extrusion industry. Useful parameters discussed include: extrusion runout; extrusion pressure; ram or extrusion speed control; and butt or extrusion discard thickness control. The chapter provides fundamental approaches to introducing and developing the design of experiments (DOE) for the aluminum extrusion plant to improve overall productivity. It also focuses on heat treatment of aluminum alloys.

This chapter describes various aspects of the billet making process and how they affect the quality of aluminum extrusions. It begins with an overview of the direct-chill continuous casting technique and its advantages over other methods, particularly for hard aluminum alloys. It then discusses the influence of casting variables, including pouring temperature and cooling rate, and operating considerations such as the make-up of charge materials, fluxing and degassing procedures, and grain refining. The chapter also provides information on vertical and horizontal casting systems, billet homogenization, and the cause of casting defects, including cracking and splitting, segregation, porosity, and grain growth.

This chapter discusses the extrusion technology of hard alloys. The chapter provides an overview of hollow extrusion for aerospace application. It presents extrusion defects related to hard alloys. The chapter describes the extrusion quality requirements for aerospace applications. It also discusses extrusion of aluminum-matrix composites. The chapter outlines the powder metallurgy process for making billets for extrusion.