Ferrous Alloys
Ferrous alloys are metallic materials that contain iron as the primary constituent, along with other elements such as carbon, manganese, and silicon. These alloys are known for their strength, durability, and magnetic properties, making them widely used in engineering and technology applications. Common examples of ferrous alloys include steel and cast iron, which are essential in construction, manufacturing, and transportation industries.
8 Key excerpts on "Ferrous Alloys"
eBook - ePub- R. E. Smallman, A.H.W. Ngan(Authors)
- 2013(Publication Date)
- Butterworth-Heinemann(Publisher)
...Chapter 14 Selected Alloys This chapter presents a survey on a few types of important metallic alloys, including alloy steels, cast irons, superalloys, intermetallic compounds, titanium alloys, aluminium alloys and copper alloys. In each material type, the general properties, classification and typical applications are discussed. Keywords Stainless steels; HSLA steels; dual-phase steels; mechanical alloying steels; ductile cast iron; superalloys; titanium alloys; intermetallic compounds; aluminium alloys; copper alloys 14.1 Introduction In this chapter we will outline some of the developments and properties of modern metallic alloys. Crucial to these materials have been the significant developments that have taken place in manufacturing, made possible by a more detailed understanding of the manufacturing process itself and of the behaviour of the material during both processing and in-service performance. Casting techniques in particular have advanced much over the past decade and now provide reliable clean material with precision. Process modelling is developing to the extent that the process designer is able to take the microstructural specification for a given composition, which controls the properties of the material, and define an optimum manufacturing route to provide the desired material and performance. Modern alloys therefore depend on the proper integration of alloy composition and structure with processing to produce the desired properties and performance. 14.2 Commercial steels 14.2.1 Plain carbon steels Carbon is an effective, cheap, hardening element for iron, and hence a large tonnage of commercial steels contains very little alloying element. They may be divided conveniently into low-carbon (<0.3% C), medium-carbon (0.3–0.7% C) and high-carbon (0.7–1.7% C) steels. Figure 14.1 shows the effect of carbon on the strength and ductility...
eBook - ePubApplied Welding Engineering
Processes, Codes, and Standards
- Ramesh Singh(Author)
- 2011(Publication Date)
- Butterworth-Heinemann(Publisher)
...Alloy steels have characteristic properties, due to some element other than carbon being added to them. Alloying elements are added to obtain several properties including the following: • Increased hardenability • Improved strength at ambient temperatures • Improved mechanical properties at low and high temperatures • Improved toughness • Improved wear resistance • Increased corrosion resistance • Improved magnetic permeability or magnetic retentivity. There are two ways in which alloyed elements are distributed in the main constituents of steel: • Dissolved in ferrite • Combined with carbon to form simple or complex carbides. The Effect of Alloying Elements on Ferrite Nickel, aluminum, silicon, copper, and cobalt are all elements which largely dissolve in ferrite. They tend to increase the ferrite’s strength by solid solution hardening. Alloying elements change the critical temperature range, eutectoid point position, and location of the alpha (α) and gamma (γ) fields on the iron-iron carbide phase diagram. These changes affect the heat-treating requirements and final properties of alloys. Effects of Alloying Elements on Carbide Carbide-forming elements, including manganese, chromium, tungsten, molybdenum, vanadium, and titanium, increase room temperature tensile properties since all carbides are hard and brittle. The order of increasing effectiveness is chromium, tungsten, vanadium, molybdenum, manganese, nickel, and silicon. Of these, nickel and silicon do not form carbides. Complex carbides are sluggish and hard to dissolve. They act as inhibitors to grain growth and often improve high temperature properties...
eBook - ePub- Jamal Khatib(Author)
- 2016(Publication Date)
- Woodhead Publishing(Publisher)
...6 Sustainability of metals and alloys in construction P. Lambert Sheffield Hallam University, Sheffield, United Kingdom Abstract Metals and alloys have played an important role in the development of society since the Iron Age. The materials employed since the industrial revolution do not exist in nature. Because of their inherent value, recycling has long been a part of the life cycle for metallic objects. Most alloys in common use are based on iron, which can quickly revert back to more stable but less useful compounds through the process of corrosion. Preventing this corrosion, whether by means of coatings, electrochemical treatments or design, offers the most cost- and energy-effective route to sustainability. Keywords Metals; Alloys; Ferrous; Stainless; Scrap; Corrosion; Protection. 6.1 Introduction Unlike most manufactured materials, metals have a long and successful history of recycling. Largely due to the significant inherent value of metals, scrap dealers have been an integral part of industrialised society since Georgian times. With the notable exception of gold and the occasional chunk of meteoric iron, metals are essentially as artificial to nature as plastic bags. Within the earth most metals only exist in stable combined states with other elements such as oxygen and sulphur. Iron, as an example, can be found as an oxide such as hematite or as a sulphide as in pyrite, the infamous ‘fool's gold’. Once we acknowledge the artificial nature of metals it is easier to appreciate the problems of oxidation and corrosion, when these essentially unstable materials convert back to the more stable compounds from which they were refined. Corrosion is a natural and normal process, reverting the metals to their lowest energy state. Ferrous or iron-based alloys such as steel can be considered to have a similar life cycle to their masters, we humans...
eBook - ePub- Jamal Khatib(Author)
- 2009(Publication Date)
- Woodhead Publishing(Publisher)
...6 Sustainability of metals and alloys in construction P. Lambert Sheffield Hallam University, UK Abstract Metals and alloys have played an important role in the development of society from the iron age onwards. The materials employed from the industrial revolution onwards do not exist in nature. Because of their inherent value, recycling has long been a part of the life cycle for metallic objects. Most alloys in common use are based on iron which can quickly revert back to more stable but less useful compounds through the process of corrosion. Preventing this corrosion offers the most cost- and energy-efficient route to sustainability. Key words metals alloys Ferrous Alloys stainless steel scrap corrosion protection 6.1 Introduction Unlike most manufactured materials, metals have a long and successful history of recycling. Largely due to the significant inherent value of metals, scrap dealers have been an integral part of industrialised society since Georgian times. With the notable exception of gold and the occasional chunk of meteoric iron, metals are essentially as artificial to nature as plastic bags. Within the earth most metals only exist in stable combined states with other elements such as oxygen and sulphur. Iron, as an example, can be found as an oxide such as hematite or as a sulphide as in pyrite, the infamous ‘fool’s gold’. Once we acknowledge the artificial nature of metals it is easier to appreciate the problems of oxidation and corrosion, when these essentially unstable materials convert back to the more stable compounds from which they were refined. Corrosion is a natural and normal process, reverting the metals to their lowest energy state. Ferrous or iron-based alloys such as steel can be considered to have a similar life cycle to their masters, we humans. Once ‘born’ their lifespan is dependent upon the appropriateness of the tasks they are given to perform and how well they are treated...
eBook - ePub- W. Bolton, R.A. Higgins(Authors)
- 2014(Publication Date)
- Routledge(Publisher)
...8 Alloys 8.1 Introduction I still have my grandmother's copper kettle. It was a wedding present from her young brother in 1877. At that time, copper was used for the manufacture of kettles, pots and pans because it was ductile and reasonably corrosion-resistant. Now aluminium, unknown commercially when my grandmother was married, has replaced copper for the manufacture of such kitchenware. In the meantime, the production of increasingly high-purity dead mild steel - which is as near as we get to pure iron commercially - has confirmed its use in the manufacture of bodywork of motor cars, domestic refrigerators, washing machines and a multitude of other items of everyday equipment. In all these products, strength is developed in otherwise soft metals by cold-work. When greater strength or hardness is required, it can only be achieved by alloying, i.e. by adding an element or elements which, by modifying the crystal structure in some way, will oppose the process of slip when stress is applied. An alloy is a mixture of two or more metals, made with the object of improving the properties of one of these metals, or, in some cases, producing new properties not possessed by either of the metals in the pure state. For example, pure copper has a very low electrical resistance and is therefore used as a conductor of electricity; but, with 40% nickel, an alloy 'constantan' with a relatively high electrical resistance is produced. Again, pure iron is a ductile though rather weak material; yet, the addition of less than 0.5% carbon will result in the exceedingly strong alloy we call steel. In this chapter, we shall examine the internal structures of different types of alloy and show to what extent the structures of these alloys influence their mechanical properties. 8.1.1 Solutions Oil and water do not 'mix'...
eBook - ePub- Roger Timings(Author)
- 2007(Publication Date)
- Routledge(Publisher)
...The initials EN now indicate that these standards are the English language versions of European standards (EN = European number). These new standards are outside the scope of this book. 4.9 Non-ferrous metals and alloys Non-ferrous metals and alloys refer to the multitude of metals and alloys that do not contain iron or, if any iron is present, it is only a minute trace. The most widely used non-ferrous metals and alloys are: • Aluminium and its alloys. • Copper and its alloys. • Zinc-based die-casting alloys. • Titanium and its alloys used in the aerospace engineering including airframe and engine components. In this book we are only interested in the first two groups. 4.9.1 Aluminium and its alloys Aluminium is the lightest of the commonly used metals. Its electrical and thermal conductivity properties are very good, being second only to copper. It also has good corrosion resistance and is cheaper than copper. Unfortunately, it is relatively mechanically weak in the pure state and is difficult to solder and weld. Special techniques and materials are required for these processes. Pure aluminium is available as foil, sheet, rod, wire and sections (both drawn and extruded). It is also the basis of a wide range of alloys. These can be classified as: • Wrought alloys (not heat-treatable). • Wrought alloys (heat-treatable). • Casting alloys (not heat-treatable). • Casting alloys (heat-treatable). The composition and uses of some typical examples of each group of aluminium alloys are listed in Table 4.6. 4.9.2 Copper and its alloys Copper has already been introduced as a corrosion resistant metal with excellent electrical and thermal conductivity properties. It is also relatively strong compared with aluminium and very easy to join by soldering or brazing. It is very much heavier than aluminium and also more costly...
eBook - ePub- Sankara Papavinasam(Author)
- 2013(Publication Date)
- Gulf Professional Publishing(Publisher)
...They can be heat-treated to increase tensile strength. FIGURE 3.21 Ductile Cast Iron. 29 Reproduced with permission from ASM International. 3.3.3 Alloy steels Alloy steel is a type of steel alloyed with several elements such as molybdenum, manganese, nickel, chromium, vanadium, silicon, and boron. These alloying elements are added to increase strength, hardness, wear resistance, and toughness. The amounts of alloying elements may vary between 1 and 50%. Alloy steels may be classified into two groups: low alloy steel and high alloy steel. The boundary between low alloy and high alloy steel is commonly accepted as 5% alloying element. For all practical purposes in the oil and gas industry, alloy steel means low alloy steel. 3.3.4 Copper alloys 30 Alloys containing more than 99.3% copper are designated as copper. Other alloys of copper include high-copper alloys, brasses, bronzes, copper-nickel alloys, nickel-silver alloys, and brazing alloys. Table 3.7 presents typical compositions of copper alloys. 31 Corrosion protection of copper and copper alloys is due to the formation of adherent surface layers, predominantly cuprous oxide (Cu 2 O). Table 3.7 General Classes of Copper Alloys 31 Copper and its alloys have high electrical and thermal conductivity, as well as good resistance to corrosion by steam. Therefore they are used for fabricating heat exchangers and condensers. Copper-nickel alloys are extensively used for fabricating components for application at elevated temperatures and pressures. Table 3.8 presents general applications of copper alloys in the oil and gas industry and their corrosion behavior. 32 Table 3.8 Some Typical Application of Copper and Copper Alloys in the Oil and Gas Industry 32 3.3.5 Stainless steels 33 Stainless steels contain a minimum of 12% chromium. They also contain nickel in excess of 6% and molybdenum...
eBook - ePub- Roger Timings(Author)
- 2008(Publication Date)
- Routledge(Publisher)
...Sometimes metals are mixed with other metals to materially alter their properties such mixtures of metals are called alloys. For example, brass is an alloy of copper and zinc. 3.3.2 Non-metals These can be elements, compounds of elements and mixtures of compounds. They include wood, rubber, plastics, ceramics and glass. Some materials are compounds of metals and non-metals. For example, naturally occurring abrasive grits, such as emery and corundum contain between 70% and 90% of aluminium oxide (a compound of aluminium and oxygen). Aluminium oxide (also known as alumina) is used in firebricks for furnace linings. Organic compounds are based on the element carbon chemically combined with other substances. Some examples of organic materials can be natural materials such as wood and some rubbers, or synthetic materials such as plastics. 3.4 Ferrous metals (plain carbon steels) Ferrous metals and alloys are based on the metal iron. They are called ferrous metals because the Latin name for iron is Ferrum. Iron is a soft grey metal and is rarely found in the pure state outside a laboratory. For engineering purposes the metal iron is usually associated with the non-metal carbon. 3.4.1 Plain carbon steels Plain carbon steels consist, as their name implies, mainly of iron with small quantities of carbon. There will also be traces of impurities left over from when the metallic iron was extracted for its mineral ore. A small amount of the metal manganese is added to counteract the effects of the impurities. However, the amount of manganese present is insufficient to change the properties of the steel and it is, therefore, not considered to be an alloying element. Plain carbon steels may contain: 0.1% to 1.4% carbon. up to 1.0% manganese (not to be confused with magnesium). up to 0.3% silicon. up to 0.05% sulphur. up to 0.05% phosphorus. Figure 3.7 shows how the carbon content of a plain carbon steel affects the properties of the steel...
