Search Results for scrap charging

This chapter traces the history of steelmaking over three millennia, from the discovery of martensite in a mining tool dating from the twelfth century B.C. to the nineteenth century development of the Bessemer and Siemens processes. It also describes the work of early metallographers who discovered many phases and microstructures associated with steel and gave them their now familiar names. The chapter concludes with a brief discussion on the emergence of continuous casting and the subsequent development of strip casting production techniques.

This chapter provides an overview of key elements in controlling the casting process, systems to confirm the quality of outgoing components, and the steps needed to launch a novel product. The discussion also provides information on process control tools and techniques; incoming material control; process control of sand preparation and system maintenance; metallic charge materials; product quality control; and melting, metallurgical, and mechanical testing.

Sand and metallic charge materials are two essential and heavy raw materials that are needed for molding and casting. This chapter focuses on planning and provision for storage and handling of the raw materials needed for casting manufacturing. The major raw materials used for molding and casting are metallic charge materials and nonmetallic materials. The chapter also presents the advantages, limitations, and applications of drum or rotary dryers (also known as rotary kiln dryers) and fluidized bed dryers (also known as vibration fluidized bed dryers).

This chapter describes the basic steps in the steelmaking process. It explains how iron is reduced from ore in the liquid state through the classic blast furnace process and in the solid state by direct reduction. It discusses the conversion of iron to steel and the technological advancements that led from open hearth steelmaking to basic oxygen processes and ultimately the electric arc furnace (EAF). It describes the versatility, efficiency, and scalability of the EAF process and its impact on recycling and sustainability. It explains how EAF refining and deoxidation practices have changed over time, and describes secondary refining processes such as degassing, homogenization, rinsing, and remelting.

This chapter provides a brief overview of iron and steel manufacturing and the major equipment involved in the process as well as identifying where casting fits into the overall process. In addition, it provides an overview of cast iron manufacturing, including the processes involved in converting pig iron into cast iron and steel.

The melting furnace is a critically important piece of equipment in a foundry; it influences the balance between the metal required by molding machines and the melting capacity. This chapter presents the features, types, advantages, and applications of furnaces suitable for iron and steels such as cupolas, induction furnaces, and arc furnaces.

This chapter discusses the processes, procedures, and equipment used in the production of iron, steel, aluminum, and titanium alloys. It describes the design and operation of melting and refining furnaces, including blast furnaces, basic oxygen and electric arc furnaces, vacuum induction melting furnaces, and electroslag and vacuum arc remelting furnaces. It also covers casting, rolling, and annealing procedures and describes the basic steps in aluminum and titanium production.

This chapter discusses the melting and conversion of superalloys and the solidification challenges they present. Superalloys have high solute content which can lead to untreatable defects if they solidify too slowly. These defects, called freckles, are highly detrimental to fatigue life. The chapter explains how and why freckles form as well as how they can be prevented. It describes the criteria for selecting the proper melting method for specific alloys based on melt segregation and chemistry requirements. It compares standard processes, including electric arc furnace/argon oxygen decarburization melting, vacuum induction melting, vacuum arc remelting, and electroslag remelting. It also addresses related issues such as consumable remelt quality, control anomalies, melt pool characteristics, and melt-related defects, and includes a section that discusses the processes involved in converting cast ingots into mill products.

The manufacture of all aluminum wrought products begins with an ingot or a continuous strip solidified from the liquid state. During molten metal processing (MMP), aluminum undergoes a series of operations that are described in this chapter including melting and alloying, recycling, molten metal treatment, control of inclusions, ingot grain refinement, and direct chill (DC) or continuous casting.

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 article explains how malleable iron is produced and how its microstructure and properties differ from those of gray and ductile iron. Malleable iron is first cast as white iron then annealed to convert the iron carbide into irregularly shaped graphite particles called temper carbon. Although malleable iron has largely been replaced by ductile iron, the article explains that it is still sometimes preferred for thin-section castings that require maximum machinability and wear resistance. The article also discusses the annealing and alloying processes by which these properties are achieved.

This chapter provides an overview of the types of melting furnaces and refractories for steel casting. It then presents information about arc furnace melting and induction melting cycles. The chapter also describes methods for the removal of phosphorous, the removal of sulfur, and the recovery of elements from slag. It then presents an overview of argon-oxygen-decarburization (AOD) refining and types of ladles. The chapter describes chemical analysis that is performed using either optical emission or x-ray spectrographs.

This chapter discusses various processes involved in the production of steel from raw materials to finished mill products. The processes include hot rolling, cold rolling, forging, extruding, or drawing. The chapter provides a detailed description of two main furnaces used for making steel: the electric arc furnace and the basic oxygen furnace. It also provides information on the classification and specifications for various steels, namely, plain carbon steels, low-carbon steels, medium-carbon plain carbon steels, and high-carbon plain carbon steels. The chapter concludes with a general overview of the factors influencing corrosion in iron and steel and a brief discussion of corrosion-resistant coatings.

The aim of every extrusion plant is the efficient production of competitive products that meet the appropriate quality requirements. This chapter discusses the processes involved in the selection and introduction of a quality management system, along with its application, advantages, and disadvantages. It describes the process chain for order processing within the quality circle and provides information on product liability legal issues. In addition, the chapter discusses the processes involved in quality control, along with its organization, responsibilities, audits, and testing.

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 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 highlights the different melting, holding, and dosing furnaces that are available for the alternative casting processes used for the production of aluminum castings. Melting furnaces are grouped into four broad categories: crucible furnaces; reverberatory furnaces (or reverbs); stack melting furnaces (also called stack melters), tower melting furnaces, or jet melting furnaces; and electric coreless induction furnaces are detailed in this chapter. Factors influencing the choice of the melting, holding, and dozing equipment are presented. Equipment for recycling machined chips is also addressed.

This article discusses the steps in the primary processing of stainless steels: melting, refining, remelting, casting, and hot rolling. It provides information of the major categories of defects in hot rolled stainless steels, namely hot mill defects, inclusion-related defects, and hot ductility-related defects.