Search Results for medium-carbon plain carbon steels

This article describes the microstructure and metallographic practices used for medium- to high-carbon steels as well as for low-alloy steels. It explains the microstructural constituents of plain carbon and low-alloy steels, including ferrite, pearlite, and cementite. The article provides information on how to reveal the various constituents using proven metallographic procedures for both macrostructural and microstructural examination. Emphasis is placed on the specimen preparation procedures such as sectioning, mounting, grinding, and polishing. The article illustrates the use of proven etching techniques for plain carbon and low-alloy steels.

Hardenability is a composition-dependent property of steel and depends on carbon content and other alloying elements as well as the grain size of the austenite phase. This article provides an overview of a wide range of testing procedures used to determine and quantify hardenability of shallow-hardening, low-carbon, plain carbon, and low-alloy medium-carbon steels ranging from classical fracture and etching, Grossmann hardenability, and Jominy end-quench testing to manual and computerized computational methods. The article then uses this as a backdrop for the implementation of the core concepts of hardenability in a variety of predictive tools for calculating hardenability. The Caterpillar 1E0024 Hardenability Calculator, a personal computer-based program, calculates the Jominy curve based on the steel composition. The article also describes the method for boron and nonboron steels, with calculation examples for 8645 steel and 86B45 steel.

This article discusses the classification of carbon steels based on carbon content, and tabulates the compositional limits of medium- and high-carbon steels based on the AISI code and other similar codes. It describes recrystallization annealing and spheroidizing of carbon steels, and discusses the classification of carbon steels for heat treatment. The article also discusses the estimation of continuous cooling curves from isothermal transformation curves. It provides information on the Jominy end-quench test and the Grossmann method and the procedures to increase hardenabilty of carbon steels. The article includes information on the purpose of tempering and heat treating guidelines for different grades of steels, including cast carbon steels.

This article describes the influence of steel chemical compositions and microstructure on machining processes. It discusses the various microstructural phases of standard carbon and alloy steels, which influence machinability. The article reviews the expected response of several traditional machining operations, such as turning, drilling, milling, shaping, thread cutting, and grinding, to the microstructure of standard steel grades. It also explains the technologies in non-traditional machining processes, such as abrasive waterjet cutting, electrical chemical grinding, and laser drilling.

The liquid nitriding process has several proprietary modifications and is applied to a wide variety of carbon steels, low-alloy steels, tool steels, stainless steels, and cast irons. This article discusses the applications, subclassifications, operating procedures, and maintenance procedures, as well as the equipment used (salt bath furnaces) and safety precautions to be undertaken during the liquid nitriding process. It describes the different types of liquid nitriding process, namely, liquid pressure nitriding, aerated bath nitriding, and liquid nitrocarburizing. Environmental considerations and the increased cost of detoxification of cyanide-containing effluents have led to the development of low-cyanide salt bath nitrocarburizing treatments. The article reviews the wear and antiscuffing characteristics of the compound zone produced in salt baths with the help of Falex scuff test.

Steel castings produced from carbon and alloy steels in any of the various types of molds and wrought steel of equivalent chemical composition respond similarly to heat treatment. They have the same weldability, and similar physical, mechanical, and corrosion properties. This article lists the specification requirements given in ASTM standards and in SAE J435c. Steel castings are classified according to their carbon or alloy composition into four general groups. Carbon steel castings account for three of these groups: low-carbon steel castings with less than 0.20″ carbon, medium-carbon castings with 0.20 to 0.50″ carbon, and high-carbon castings with more than 0.50″ carbon. The fourth group, low-alloy steel castings, is generally limited to grades with a total alloy content of less than 8″. The article presents graphical representations of the mechanical properties of cast carbon steels as a function of carbon content for different heat treatments.

Case hardening involves various methods and each method has unique characteristics and different considerations in the selection of steels This article reviews the various grades of carburizing steels, carbonitriding steels, nitriding steels, and steels for induction, or flame hardening. This review is based on their process characteristics, compositions, applications, and mechanical properties, which help in selecting steels for case hardening.

Hardenability is usually the single most important factor in the selection of steel for heat-treated parts. The hardenability of steel is best assessed by studying the hardening response of the steel to cooling in a standardized configuration in which a variety of cooling rates can be easily and consistently reproduced from one test to another. These include the Jominy end-quench test, the carburized hardenability test, and the surface-area-center hardenability test. This article discusses the effects of varying carbon content as well as the influence of different alloying elements on hardenability of steels. The basic information needed before a steel with adequate hardenability can be specified as the as-quenched hardness required prior to tempering to final hardness that will produce the best stress-resisting microstructure; the depth below the surface to which this hardness must extend; and the quenching medium that should be used in hardening.

Hardening and depth of hardening of steel is a critically important material and process design parameter. This article presents a selective overview of experimental and predictive procedures to determine steel hardenability. It also covers the breadth of steel hardenability, ranging from shallow, to very difficult to harden, to air-hardening steels.

This article describes the heat treating (stress relieving, normalizing, annealing, quenching, tempering, martempering, austempering, and age hardening) of different types of steels, including ultrahigh-strength steels, maraging steels, and powder metallurgy steels. Tabulating the recommended temperatures for normalizing and austenitizing, it provides information on mechanism, cooling media, principal variables, process procedures, and applications of heat treating. In addition, the article gives a short note on the cold and cryogenic treatment of steel.

This article discusses the properties of threaded fasteners made from carbon and low-alloy steels containing a maximum of 0.55% carbon. It provides guidelines for the selection of steels for bolts, studs, and nuts intended for use at temperatures between -50 and 370 deg C. The article also discusses steels rated for service above 370 deg C and describes internationally recognized grade designations. The specifications provided can be used to outline fastener requirements, control manufacturing processes, and establish functional or performance standards. The most commonly used protective metal coatings for ferrous metal fasteners; zinc, cadmium, and aluminum; are described as well.

Steel castings can be made from any of the many types of carbon and alloy steel produced in wrought form. They are divided into four general groups according to composition. Carbon and low-alloy steel castings can meet a wide range of application requirements because composition and heat treatment can be selected to achieve specific combinations of properties, including hardness, strength, ductility, fatigue, and toughness. This article discusses physical, mechanical, and engineering properties as well as fatigue properties and the effects of section size and heat treatment. Highly stressed steel castings for aircraft and for high-pressure or high-temperature service must pass rigid nondestructive inspection.

The machinability of carbon and alloy steels is affected by many factors, such as the composition, microstructure, and strength level of the steel; the feeds, speeds, and depth of cut; and the choice of cutting fluid and cutting tool material. This article describes the influence of the various attributes of carbon and alloy steels on machining characteristics. It lists the relative machinability ratings for some plain carbon steels, standard resulfurized steels, and several alloy steels. The addition of lead to carbon steels is one of the means of increasing the machinability of the steel and improving the surface finish of machined parts. Low carbon content of carburizing steels may be beneficial to tool life and production rate. The sulfur content of through-hardening alloy steels can significantly affect machining behavior. Cold drawing generally improves the machinability of steels containing less than about 0.2% carbon.

Carburization is the process of intentionally increasing the carbon content of a steel surface so that a hardened case can be produced by martensitic transformation during quenching. Like carburizing, carbonitriding involves heating above the upper critical temperature to austenitize the steel. This article introduces the fundamentals, types, advantages and limitations, and the complications of various forms of carburizing, namely, pack carburizing, liquid carburizing or salt bath carburizing, gas carburizing, and low-pressure (vacuum) carburizing. The related process of carbonitriding is also briefly described in the article.

This article addresses classifications and designations for carbon and low-alloy steel sheet and strip product forms based on composition, quality descriptors, mechanical properties, and other factors. Carbon steel sheet and strip are available as hot-rolled and as cold-rolled products. Low-alloy steel sheet and strip are used primarily for applications that require the mechanical properties normally obtained by heat treatment. The descriptors of quality used for hot-rolled plain carbon steel sheet and strip and cold-rolled plain carbon steel sheet include structural quality, commercial quality, drawing quality, and drawing quality, special killed. The surface texture of low-carbon cold-rolled steel sheet and strip can be varied between rather wide limits. The modified low-carbon steel grades discussed in the article are designed to provide sheet and strip products having increased strength, formability, and/or corrosion resistance. The article also summarizes the key operations involved in the three alternative direct casting processes: thin slab, thin strip, and spray casting.

This article, primarily focusing on atmospheric corrosion of carbon and low-alloy steels, describes the factors that must be considered by alloy casting users in material selection. It presents compositions of cast steels tested in atmospheric corrosion in a tabular form. The article graphically presents the results of a research program that compared the corrosion resistance of nine cast steels in marine and industrial atmospheres. It provides a comparison of corrosion rates of cast steels, malleable cast iron, and wrought steel after three years of exposure in two atmospheres. Conclusions drawn from these tests are also presented.

This article explains cooling mechanisms involving saltwater solutions used as quenchants. The analyses of cooling power include studies of cooling curves, heat-transfer coefficients, and cooling rates. The influence of other bath parameters, such as temperature and agitation, is also discussed. The article discusses solute additions and several factors impacting quenching.

This article provides a detailed discussion on the factors involved in the selection of steels for austempering, including section thickness limitations of steel parts and modifications of austempering practice. The selection of steel for an austempered component is based on the processing characteristics of the heat treating equipment employed. It is also based on the hardenability and transformation characteristics of the steel alloy as indicated by time-temperature-transformation and isothermal-transformation diagrams. The article contains tables that compare the dimensional changes that occur in stabilizer bars as a result of oil quenching and tempering with those that resulted from austempering. It also discusses the production applications of austempering and the problems encountered in austempering together with their solutions.