Three general classifications are used to identify stainless steels. Mechanical properties of ferritic stainless steels at. F amilies of stainless steel 9 10 medium and high crbased jfemh1 15cr1. Another common characteristic of austenitic stainless steel alloys is that they tend to be nonmagneticthough. Pdf high strength medium carbon austenitic stainless steels have been developed through partial and total replacement of nickel by nitrogen. Duplex stainless steels offer several advantages over the common austenitic stainless steels. Stainless steel the four types of steel metal supermarkets. With specific restrictions in certain types, the stainless steels can be. European stainless steel producers national stainless steel development associations development associations of the alloying element industries. Cutlerygrade stainless generally contains more than percent chromium, the oxide of which helps to form a passive film that protects against corrosion and staining. Surface imperfections are sometimes erased by grinding, which can leave behind shiny spots. Physical properties of stainless steels the attached collection of data reflects inquiries directed to stainless steel development associations.
Corrosion resistance of stainless steels most materials decay over time material. The numbers associated with stainless steel grades and types also refer to the amount of chromium, nickel, iron, manganese, titanium, etc, that make up the grade. The various types of stainless steel are identified and guidance given on welding processes and techniques which can be employed in fabricating stainless steel components without impairing the corrosion, oxidation and mechanical. As in other types of stainless steels, it is the content of chromium that imparts the property of corrosion resistance to the alloy. This publication is being made available in pdf format as a benefit to members and customers. Stainless steel is an alloy of several different types of metal that, when combined, are stronger and more durable than when they are separate. Atlas steels metal distribution stainless steel grade chart atlas steels specialty steels product reference manual section 9. This film is called the passive layer and forms rapidly in ordinary atmospheres. Stainless steel grades chart pdf types of stainless steel. It is a nonmagnetic steel which cannot be hardened by heat treatment, but instead. Austenitic steels are nonmagnetic and nonheattreatable, and generally contain 18% chromium, 8% nickel and less than 0. Reference is often made to stainless steel in the singular sense as if it were one material.
The carbon present in the form of ironcarbidefe3c increases the hardness and strength of the steel. The duplex types are not hardenable by heat treatment but are stronger than either. These metals are magnetic but are not heat treatable, they can be strengthened by cold working. Most stainless steels have similar designations, some of which are given in tables 2 and 3. These steel standards are helpful in guiding metallurgical laboratories and refineries, product manufacturers, and other endusers of steel and its variants in their proper processing and application procedures to ensure quality towards safe use. Introduction to stainless steels asm international. Martensitic stainless steels are used when corrosion resistance andor oxidation resistance are required in combination with either high strength at low temperatures or creep resistance at elevated temperatures. Stainless steel grade designations in europe, stainless steel types are usually defined by designations given in euronorm en 10088 stainless steels for general purposes. Figure 4 6 shows how composition variations have led to many related stainless steels that have evolved from the basic s30400 304 composition. Aisiamerican iron and steel institute steels these steels are generally used in machine construction. Ferritic stainless steels are classified in the 400 series, usually with 10% to 30% chromium content, and are often chosen for their excellent corrosion resistance and elevated temperature oxidation resistance. They are usually limited in use to relatively thin sections due to lack of toughness in welds.
By altering the composition, as indicated by the arrows and text in the figure, various compositions are. Therefore, the reduction of mechanical properties of ferritic stainless steels under fire conditions is largely unknown. Compared to other types of stainless steel, it is usually limited to use of relatively thin sections, due to of a lack of toughness in welds. In the fourth part of our video blog series, we look at the various types of stainless steels. A very high carbon, chromium stainless steel with additional amounts of molybdenum.
Ferritic stainless steels have the bodycentered cubic structure of ferrite, but contain between 11 and 30 wt% chromium in solid solution davis, 1994. A typical composition has 22% chromium, 5% nickel and 3% molybdenum with a small addition of nitrogen. How to select the right stainless steel for adequate corrosion resistance structural applications other applications 5. Austenitic steels have austenite as their primary phase face centered cubic crystal. Precipitationhardening stainless steels table 4 are chromiumnickel types, some containing other alloying elements, such as copper or aluminum. These efforts were similar and overlapped significantly. Different stainless steel qualities are used for door hardware, such as aisi 201, 304, 316 or 430. Types 405, 409, 430, 422 and 446 are representative of this group. This steel has good edge holding properties and high corrosion resistance, but is more difficult to resharpen than lower chromium steels. They are the alloys of iron, carbon and other elements such as silicon, phosphorus, sulphur and manganese. They can be hardened by solution treating and aging to high strength.
Varying additions of nickel, molybdenum, nitrogen, copper, manganese, wolfram, titanium, niobium, cerium and other elements may also be present. Types of stainless steels austenitic stainless steels include the 200 and 300 series of which type 304 is the most common. Austenitic grades are the most commonly used stainless steels accounting for more than 70% of production type 304 is the most commonly specified grade by far. Appendices printed november 2000 1 s9 chemical analysis % speci. Austenitic stainless steels have different compositions and properties but also have many common characteristics. Different types of steels pdf applications, chemical composition, stainless steels, properties etc steels are widely used materials in industry. Austenitic stainless steels have many advantages from a metallurgical point of view. Table 4 precipitation hardening stainless steels uns uns s800 s17400 s15500 s17700 duplex stainless steels table 5 have. Martensitic stainless steel an overview sciencedirect. Different types of steels pdf applications, chemical composition, stainless steels, properties etcsteels are widely used materials in industry. Interest in nitrogen as an alloying element is growing and many stainless steel grades, both austenitic and duplex. The particular application for which stainless steel will be used determines the type and grade of. The materials cannot be hardened by heat treatment and are essentially nonmagnetic in the annealed condition.
These designations follow the werkstoff numbering system for steels originally developed in german e. They are produced in cast, powder metallurgy pm, and wrought forms. Some ferritic stainless grades such as types 409 and 405 cost less than other stainless steels. The 3 main types of stainless steel are austenitic, ferritic, and martensitic. The enclosed documents are for information only and cannot replace reference to either en 10088, or en 10095. Available wrought product forms include plate, sheet, strip, foil, bar, wire, semifinished prod.
The stainless steel family international stainless steel. You know what, there are more than 3500 grades of steels available which result in different physical, chemical and environmental properties even though steel is the composition of iron and carbon. These designations follow the werkstoff numbering system for steels originally developed in. Ferritic these steels are based on chromium with small amounts of carbon usually less than 0. Austenitic steels form the largest portion of the global stainless steel market and are often used in food processing equipment, kitchen utensils, and piping. The primary alloying additions are chromium and nickel. The different types of stainless steel stainless structurals. Duplex stainless steels have a balanced or mixed structure of austenite and ferrite and as a result, have characteristics of both these basic types. Ferritic stainless steels are nonhardenable fecr alloys. Four different types of stainless steel ferritic stainless steel. Martensitic steels contain 1117% chromium, less than 0.
The family of precipitation hardening stainless steels can be divided into three main types low carbon martensitic, semiaustenitic and austenitic typical compositions of some of the steels are given in table 1. Duplex stainless steels offer advantages in many applications due to their resistance to chloride stresscorrosion cracking scc in addition to excellent pitting resistance. Ferritic stainless steels are ideal for applications ranging from appliances to nextgeneration, hot end exhaust systems. These are the most frequently used types of stainless steels. Different types of steels pdfstainless steels, chemical. Jfe offers a wide range of crbased stainless steel types. Carbon steels and alloy steels are designated by a four digit number, where the first digit indicates the main alloying elements, the second digit indicates the secondary alloying elements, and the last two digits indicate the amount of. Production of stainless steels with specific restrictions in certain types, the stainless steels can be shaped and fabricated in conventional ways. For example, the number 316 contains 16%18% chromium and 11%14% nickel. Precipitation hardening is achieved by the addition of copper, molybdenum, aluminium and titanium either singly or in combination. Chromium reacts strongly with oxygen to form a very thin, invisible, stable oxide film on the surface of the stainless steel.
Few stainless steels contain more than 30% cr or less than 50% fe. The prime objectives of euro inox are to create awareness of the unique properties of stainless steels and to further its use in existing applications and in new markets. Stainless steels are those steels that have a chromium content of at least 11%. Types of stainless steel stainless steels are steel alloys that contain more than 10. The most familiar stainless steel is probably type 304, sometimes called t304 or simply 304. Ferritic stainless steels are essentially nickelfree. Austenitic stainless steels tend to have a high chromium content compared to other steel alloys, giving them a higher resistance to corrosion. By adding and subtracting various elements to stainless steel, engineers have been able to create many different varieties of the alloy, each with their own characteristics and uses. Ferritic stainless steel an overview sciencedirect topics. There are essentially three types of martensitic stainless steels. The duplex grades are highly resistant to chloride stress corro sion. Classification of stainless steels total materia article.
Based on chromium with small quantities of carbon, ferritic stainless steel has a similar microstructure to both carbon and low alloy steels. It is also referred as constructional steels or structural steels. They achieve their stainless characteristics through the formation of an invisible and adherent chromiumrich oxide surface film. Type 304 188 is an austenitic steel possessing a minimum of 18% chromium and 8% nickel, combined with a maximum of 0.
The sae steel grades system is a standard alloy numbering system sae j1086 numbering metals and alloys for steel grades maintained by sae international in the 1930s and 1940s, the american iron and steel institute aisi and sae were both involved in efforts to standardize such a numbering system for steels. Stainless steels are ironbased alloys containing at least 10. The 18% minimum chromium content provides corrosion. These steels have a similar microstructure to carbon and low alloy steels. However, past research on design of stainless steel has been mainly focused on the austenitic and duplex grades. These steels have a great potential for application in the construction industry. It seems there are a million different stainless steel grades. There are a number of basic types of stainless steel finishes. Ferritic stainless steels are essentially nickel free. These three types of steels are identified by their microstructure or predominant crystal phase. This easytoread stainless steel grades chart pdf has all you need to know on.
Types of stainless steel in addition to chromium, nickel, molybdenum, titanium and niobium, other elements may also be added to stainless steels in varying quantities to produce a range of stainless steel grades, each with different properties. Stainless steels are made corrosion resistant by the addition of chromium. Stainless steel grade numbers identify the quality, durability, and the temperature resistance. Most kitchen knives are made from martensitic stainless steel. Type 304 surgical stainless steel is an austenitic steel containing 1820% chromium and 810% nickel. This finish is mainly used for industrial applications such as furnace arch. For example, the saeaisi designation system lists nearly 60 stainless steels in four differentgeneralsubdivisions. They have less than about 5% total addition of elements such as cr, ni, cu, mn, mo, v, etc. It compares the types, grades, chemistries, finishes and applications of stainless steels produced by ak steel. Stainless steels are chosen because of their enhanced corrosion resistance, high temperature oxidation resistance or their strength.