Surface Hardening of Steels: Understanding the BasicsAnnotation A practical selection guide to help engineers and technicians choose the mot efficient surface hardening techniques that offer consistent and repeatable results. Emphasis is placed on characteristics such as processing temperature, case/coating thickness, bond strength, and hardness level obtained. The advantages and limitations of the various thermochemical, thermal and coating/surface modification technologies are compared |
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Expressions et termes fréquents
abrasive AISI alloy steels ammonia applications ASM International atmosphere carburizing austenite grain bending fatigue boride layer boriding burizing carbide carbon content carbon gradient carbon potential carbonitrided carburized steels cementite coating components composition compound layer compressive stresses cooling core hardness corrosion resistance cyanate cyanide cycle deposit depth diffusion effect electroless nickel endothermic fine finish first fracture furnace gas carburizing gas nitriding gears hardfacing heat treating heat treatment higher HVOF increased induction hardening induction heating influence intergranular intergranular fracture laser liquid nitriding load martensite material metal microcracks microstructure nitriding nitrocarburizing nitrogen oxidation pearlite plasma plating produced profile properties reheating residual stresses retained austenite salt bath shot peening shown in Fig specific specimens stainless steels substrate sufficient surface carbon surface hardening Table tempering thermal spray thickness tion tool steels ture typical vacuum carburizing wear resistance welding workpiece zone
Fréquemment cités
Page 312 - NOTE — All these changes except the formation of martensite occur at lower temperatures during cooling than during heating, and depend on the rate of change of temperature.
Page 312 - The temperature at which transformation of austenite to ferrite or to ferrite plus cementite is completed during cooling.
Page 68 - R is the ratio of the minimum stress to the maximum stress in a cycle and is known as the
Page 312 - Transformation Temperature — The temperature at which a change in phase occurs. The term is sometimes used to denote the limiting temperature of a transformation range. The following symbols are used for iron and steels: Accm — In hypereutectoid steel, the temperature at which the solution of cementite in austenite is completed during heating. Ac, — The temperature at which austenite begins to form during heating.
Page 89 - Micon 78: Optimization of Processing, Properties, and Service Performance Through Microstructural Control, ASTM STP 672, 207, American Society for Testing and Materials, Philadelphia, PA, (1979).
Page 177 - ... of atmospheric humidity will cause spatter at contact with molten salt. Remove Impurities (Sludges): The method that has been successfully used to increase the longevity of molten baths is periodic cleaning. Carbonates, the main oxidation products, are readily removed by cooling the bath to 850°F and allowing the precipitated salt to settle to the bottom of the salt pot. Perforated ladles can be used to spoon sludge from the bottom. Minimize Dragout: Dragout refers to the excess bath media that...
Page 162 - ... above hazardous waste sources, supportive operations in heat treating processes such as parts cleaning or surface coating generate additional hazardous waste. Plating, as an example, is performed to prevent carburizing or nitriding of a metal workpiece or its selected parts during the heating cycle. Plated deposits of bronze or copper are the most common stop-off coatings. Nickel (including electroless nickel), chrome, and silver are effective also but their higher cost restricts their use to...
Page 125 - Cyanides are violent poisons if allowed to come in contact with scratches or wounds — for example, on the hands; they are fatally poisonous if taken internally. Also, fatally poisonous fumes are evolved when cyanides are brought into contact with acids. The white deposits that form on hoods and cooler furnace parts consist mainly of sublimed sodium carbonate, with small amounts of sodium, potassium, and barium salts, but may contain some cyanide as the result of splashing. When cyanide salts are...
Page 198 - ... must be disposed of as hazardous waste every few months to every few years depending upon service. Alter Raw Materials: The increased cost of detoxification of cyanide-containing effluents has led to development of a low cyanide salt bath for nitrocarburizing treatments. In one patented process, it confers sulfur, nitrogen, and presumably carbon and oxygen to surfaces of ferrous materials. The process is unique in that lithium salts are incorporated in the bath composition. Cyanide is held to...
Page 125 - The parts may then be transferred to an agitated hot dilute-alkaline cleaner having high sequestering properties. (Silicated cleaners and those containing carbonates or phosphates are not recommended because of the formation of insoluble barium compounds in the presence of barium-containing salts.) If a white, powdery overlay of barium carbonate remains on the parts...
Informations bibliographiques
| Titre | Surface Hardening of Steels: Understanding the Basics |
| Rédacteur | Joseph R. Davis |
| Éditeur | ASM International, 2002 |
| ISBN | 1615032509, 9781615032501 |
| Longueur | 364 pages |
| Exporter la citation | BiBTeX EndNote RefMan |