Corrosionpedia what is electron beam hardening ebh. Pdf to text batch convert multiple files software please purchase personal license. Electron beam hardening ebh, with some special characteristics in comparison to other heat treatment technologies, allows beam deflection frequencies of up to 100 khz. Electron beam hardening is a material hardening process that uses an organized column of electrons as an energy source. It has been shown to improve tribological properties of the metal alloys and ceramics 49, or their corrosion behaviour 10, 11. The technology of laser hardening is one of the key competences of erlas. Laser hardening is ideally suited for contact surface hardening where the precise application and fast treatment times lead to minimum heat input, reducing distortion to a. For carbon steels, power densities used are from to 1500wcm 2 with dwell time of 1 to 2 s during laser surface hardening, a laser can generate very intense energy.
Laser heat treating makes use of the laser energy to rapidly and efficiently heat a selected area of the surface of a metal component above the transformational temperature. Laser surface hardening is a promising process for enhancing the surface properties of a component. The laser beam heats up the outer surface of the material just below the melting point. Introduction to surface hardening of steels revised by michael j. Understanding the basics is a practical selection guide to help engineers and technicians choose the optimum surface hardening treatment for a given application from an ever increasing number of options. Laser hardening laser cladding services oerlikon metco.
Laser peening lp, or laser shock peening lsp, is a surface engineering process used to impart beneficial residual stresses in materials. Cncautomation provides precise beam depth and coverages. Laser hardening with the development of a better understanding of the process, predictive modeling for fixing optimum laser processing parameters, and online process monitoring and control, is now an established manufacturing process for enhancing the mechanical properties of selected surface areas of engineering parts and is becoming popular. Laser hardening of these areas offers a real alternative to flame or induction hardening where distortion or reliability often presents problems. This method uses a laser beam of larger dimensions approximately tens of millimeters and is particularly suitable for the processing of larger areas without significant shape complexities. Laser surface hardening uses a welldefined, intense energy beam as a heat source. Heat treatment and surface hardening i 82,734 views. Laser surface transformation hardening becomes one of the most modern processes used to improve fatigue and wear properties of steel surfaces. Engel, basics of laser heat treating, in, source book on applications of the laser in metalworking. The results show that spiral scanning matching with adaptable technological parameters and water cooling achieve remarkable hardenability with less deformation, which satisfy the.
The electromagnetic radiation of a laser beam is absorbed within the first few atomic layers for opaque materials, such as metals, and there are no associated hot gas jets, eddy currents or even radiation spillage outside the optically defined beam area. Laser surface modification technology includes laser transformation hardening, laser. Heat is generated by absorbing the laser radiation on the surface and the material is quenched by heat transportation inside. Laser surface transformation hardening not only increases the wear resistance. Chapter 4 fundamentals of laser material interaction and application to multiscale surface modi. When hardened tracks has to be overlapped each other, in the overlap area originates. The power densities used in laser surface hardening are in the range of 500 to 5000 wcm 2 with dwell times in the range of 0. The bombardment of the electron column on the materials surface creates heat, which is increased until the material or the surface of the material. A laser hardening device for forming a hardened layer on the surface of an object irradiated by a laser beam is so arranged as to emit a laser beam which is linearly polarized in the incidence plane containing the normal to the surface and the optic axis of the laser beam irradiating the surface.
This article illustrates the principles of different thermal electron beam technologies, including beamdeflection, continuous eb interaction, eb flash, as well as multifield. Trials of laser hardening were carried out under different conditions, with different modes of laser guidance over the specimen surfaces, and with different degrees of path overlapping. Laser surface hardening lsh has become the most vital process to increase the hardness of a mild steel surface, especially to overcome the wear issues in machining parts, where mild steel was hugely applied due to its advantages such as less air pollution, low cost of maintenance and easy to handle compare to other conventional surface hardening process. The coating to enhance the laser absorptivity was brushed on the surface of 174ph stainless steel.
The result of the hardening process to the affected area is fine martensitic grain structure. Introduction to surface hardening of steels asm international. Despite that, hardening of heavy moulds for automotive industry is in high demand. The effect of laser surface hardening on surface hardness. It has been proved that with a constant hardening depth the results hardness.
The effect of laser irradiation with different numbers of laser shots on the microstructure, the surface, and the hardness of gun metal alloy was studied by a krf pulsed excimer laser system, xray diffraction, raman spectroscopy, scanning electron microscopy, and vickers hardness test. The laser has some unique properties for surface heating. In order to trace the radiating running influence upon hardening depth and level, surface scanning speed within 12,524,5 mms range were experimented. The power density of laser beam is usually expressed as watts per square centimeter.
Laser focal height lfh, pulse width lpw, scanning speed lss, and power lp varied during the experiments. Laser surface hardening process is the method of hardening surface by inducing rapid self quenching of laser injected area through transfer of surface heat to inside. Aside from conventional hardening methods, the market share for lasers in functional surface hardening is in creasing. The model predicts the temperature distribution in the vicinity of a moving ringshaped laser spot around the periphery of the outer surface of a cylinder, or the inner surface of a hollow cylinder. The control of these factors using predictive modeling approaches to achieve desired. Heat treating and hardening a surface with a laser is simple. Laser surface hardening process is a very promising hardening method for ferrous and nonferrous alloys where transformations occur during cooling a er laser melting in the solid state. Surface hardening using laser heat treating is used to improve the wear resistance of the surface of a part without affecting the tougher interior of the part. Electron beam surface hardening steel heat treating. Homogeneous heat treatment, suitability for all component. Heat flow in cylindrical bodies during laser surface. Pdf on may 25, 2004, janez grum and others published 6 laser surface hardening find, read and. The laser hardening experiments were carried out by a 7kw continuous wave co 2 laser system with a cnc controlled working table.
Laser technology is ideal for performing laser transformation hardening in a manufacturing environment because of the. Feasibility studies on underwater laser surface hardening process. Laser surface hardening of cast iron is not trivial due to the materials heterogeneity and coarsegrained microstructure, particularly in massive castings. To increase laser radiation energy absorption it was used a zinc oxide absorbent cover on the surface to be worked. The paper introduces the laser surface hardening processing with 5 kw cnc co 2 laser for cam shaft made of 45 steel. The processes of surface hardening with laser are generally usable for all materials at which classical hardening methods can be used due to the adequate carbon content. Laser beam was focused by two special integral lenses to get two kinds of beams during the two laser hardening processes. Applications examples of laser hardening of circular shape surfaces are shown in fig. Experimental investigation of laser surface hardening of. During laser hardening, also known as surface layer hardening, the energy from the laser beam is applied directly to the component surface. Rapid cooling of the melt pool produces martensite, which increases the wear and abrasion. Laser surface hardening of aisi h tool steel jaeho lee, jeonghwan jang, byeongdon joo, youngmyung son, younghoon moon school of mechanical engineering, pusan national university, busan, 609735, korea received 18 june 2008. Laser hardening techniques on steam turbine blade and. Another method is explosive hardening, where a layer of explosive coated on the surface is blasted the.
Laser surface hardening steel heat treating fundamentals. Method of laser hardening of a surface area of a workpiece, such as a surface of a journal of a crankshaft, comprising. Laser heat treating for surface hardening group six. Makes harder outer layer and also introduces compressive stresses. Laser hardening is a heat treatment process or surface hardening process in which a laser beam is used to heat the surface of a metal part and then let it quickly cool down in surrounding air. At laser hardening, only the especially stressed areas of the components are locally hardened, e. While improving the wear properties of metals, the process allows metal to maintain ductility. The thermal mass of the component is all that is required to achieve quenching. This process is used exclusively on ferrous materials suitable for hardening, including steels and cast iron with a carbon content of more than 0.
Laser surface hardening is a technique that has been used and investigated since the 1970s. In the case of circular shapes, laser hardening is performed by rotating the workpiece while irradiating one point of the surface with the spotlight. Materials free fulltext laser surface hardening of. As the laser beam moves on, the surrounding material cools down the hot surface very quickly in a process known as selfquenching. The first one is the economical aspect mostly high initial costs for. Experimental investigations of laser surface transformation hardening, laser remelting and laser shock processing were performed. This article provides a brief discussion on the various conventional surface modification techniques to enhance the surface and mechanical properties of ferrous and nonferrous alloys. Chapter 4 fundamentals of lasermaterial interaction and. The microstructure of the treated zone was characterized by optical om and field emission scanning electron microscopy fesem. Surface hardening basics of laser heat treating, in applications of the laser in metalworking, ed. Since development of the worldwide first hardening machine equipped with a high power diode laser in the year 1998 erlas offers laser hardening systems of the type erlaser hard and uses them successfully in a job shop for customers. The deep, high magnitude compressive residual stresses induced by laser peening increase the resistance of materials to surface related failures, such as fatigue, fretting fatigue and stress corrosion cracking.
As soon as the laser beam no longer acts, the heat is conducted into the base material of the work piece self quenching and a hard, martensitic joint emerges. Methods of laser surface hardening laser widebeam hardening. Metzbower american society for metals, metals park, 1981, pp. Introduction laser hardening is a hardening technology using a laser beam as a heating source. The influence of 100500 laser shots was irradiated on the surface hardness profile and on the. Laser surface hardening is a noncontact process that provides a chemically inert and clean environment as well as flexible integration with operating systems. In the case of hardening a flat surface, laser hardening can be applied like a conventional induction. Arnold abstract lasers provide the ability to accurately deliver large amounts of energy into con. In recent years, industrial application of laser hard. Laser beam hardening erlas erlanger lasertechnik gmbh. Materials free fulltext experimental and numerical. Us108528b2 method and system for laser hardening of a. Pdf pid control of laser surface hardening of steel.
The device comprises a first concave mirror for condensing the laser beam the incidence plane, and. During the laser skin hardening, the material carbonaceous material is heated up for a short time above austenitizing temperature and is transubstantiated by fast cooling down into the martensitic structure. Lasers are an excellent source of surface hardening for ferrous material with carbon content of more than 0. Laser surface hardening thermomechanics of technological. Chatterjee, bodycote surface hardening, a process that includes a wide variety of techniques table 1, is used to improve the wear resistance of parts without affecting the more soft, tough interior of the part. Using surface laser hardening, only parts that are subject to particularly high stress are hardened locally, e. Application of laser hardening technology to sintered parts. The major advantage of diode laser surface hardening is the high processing speed with precise casedepths resulting in negligible distortion. Specimens are heattreated separately at certain plate and edge position by using a diode laser to carry out suitable surface hardening. Laser hardening with this method, segments irradiated by the laser can locally be hardened, as well as the selective processing of threedimensional and irregular work pieces. Laser hardening with the development of a better understanding of the process, predictive.
The results show that, the hardness of asreceived aisi h tool steel is approximately hv 240, and the hardness after laser surface heat treatment is around hv. Important parameters of heat treatment with the laser beam are. Laser hardening is a method aimed at improving component wear behaviour. At the locations in erlangen and amurrio, spain three laser beam. Laser surface hardening of aisi h tool steel sciencedirect. Laser surface hardening lsh is one of the most widely used surface hardening process which can be applied to almost the whole range of metallic materials in todays. Pdf laser surface hardening lsh is one of the most widely used surface hardening process which can be applied.
However, technical application of the laser surface melting is currently limited due to several causes. In this process, the material properties and the heating parameters are the factors that present the most significant effects on the hardened surface attributes. Optimization of laser beam transformation hardening by. Laser surface transformation hardening lsth of aisi 4 was investigated by a nd. Research article feasibility studies on underwater laser. Comparison of different techniques of laser surface hardening. It can be used to predict the depth of case in laser surface transformation hardening.
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