Old Answer, better
Laser Hardening: 00:17 14.04..2011
In conventional methods of heat treatment, the component is heated to the required temperature and then quenched in oil or water to achieve the desired hardness at the surface. In most industrial applications, wear occurs only in selected areas of the component. Rapid advances in laser technology in the past decade have made it possible to perform various operations such as heat treating, glazing, alloying, and cladding on surfaces of materials, resulting in better physical properties of the surface and improved performance in a given enviroment. Because a laser is an expensive source of energy, it is used only in cases where it offers some technical or economic benefits compared to conventional methods. The advantage of using a laser for surface processing results from its highly directional nature and from the ability to deliver controlled amounts of energy to desired regions. In laser heat treatment, which involves using a laser as a heat source, the beam energy is applied to harden a surface with the rest of the component acting as a heat source, the beam energy is applied to harden a surface with the rest of the component acting as a heat sink. Because ferrous materials are very good heat conductors, the high heal fluxes generated by laser are most suitable to heat surface layer to austenitization levels without affecting the bulk temperature of the sample. The ensuing self-quenching is rapid enough to eliminate the need for external quenching to produce the hard martensite in the heated surface.Thus a highly wear resistant surface with the desired core properties of the component can be obtained.
(Joseph R. Davis, Surface Hardening of Steels: Understanding the Basics, p. 264)
New Answer
The principles of laser hardening are similar to those of conventional through-hardening, although the time scales involved are involved are typically an order of magnitude shorter. The laser beam is shaped into an appropriate pattern for the required hardened region and scanned over the component. Hardenable ferrous alloys are the most suitable for laser hardening. The temperature at a required depth is raised to fully austenitize the microstructure, without melting the surface. During the peak of the thermal cycle the microstructure is homogenized by solid state diffusion. On cooling, austenite transforms to martensite with a uniform carbon distribution and hardness. An additional benefit is the development of a compressive residual stress state at the surface because of the 4% volume increase associated with the transformation of austenite to martensite.
( Ion J., Laser Processing of Engineering Materials:Principles, Procedure, p. 222)
2. Impact Forging
Old Answer
Impact Forging
Press forging employs a slow-squeezing action that penetrates throughout the metal and produces a uniform metal flow.
In hammer or impact forging, metal flow is a response to the energy in the hammer-workpiece collision. If all the energy can be dissipated through flow of the surface layers of metal and absorption by the press foundation, the interior regions of the workpiece can go undeformed. Therefore, when the forging of large sections is required, press forging must be employed.
(Kutz M., Mechanical engineers' handbook: Manufacturing and management, p. 250)
New Answer,better
In hammer or impact forcing, the metal flows to dissipate the energy imparted in the hammer-workspace collision. Speeds are high, so the forming tine is short. Contact times under load are on the order of miliseconds. There is little time for heat transfer and cooling of the workpiece, and the adiabatic heating that occurs during deformation helps to minimize chilling. It is possible, however, that all of the energy can be dissipated by deformation of just the surface of the metal (coupled with additional absorption by the anvil and foundation), and the interior of the workpiece remains essentially underformed. Consider the deformation of a metal wood-splitting wedge after it has been struck repeatedly by a sledge hammer. The top is usually "mushroomed" while the remainder retains the original geometry and taper.
(Black J., Degarmo's Materials and Processes in Manufacturing, p. 411)
3. Linishing Machine(Surface Treatment)
No old answer
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New Answer
Linishing Machine - Automatic mirror polishing machine capable of polishing one or more parts at a time on the same polishing band or disc.
(Ramalingam K., Handbook of Mechanical Engineering Terms, p. 79)
4. Canadize (in Magnaplate) (Coating)
Old Answer
Canadize (titanium) (in Magnaplate) (11:31 am 15.04.2011)
--A system for hardfacing each material has been developed which is basically an electrochemical process. The synergistic coating system is still far the best for a wear application, however, and special fluoropolymers or dry are infuesed into the hardfacing.
--For titanium synergistic coating is called Canadize. For titanium application thickness is difficult to build up, so the normal application thickness is between 0.0002 and 0.0005 in.
--A classic application for Canadizing is titanium hardware for aircraft. Such components are anodized with an infusion to a thickness of 0.0002 - 0.0004 in. to prevent the titanium from seizing.
--A system for hardfacing each material has been developed which is basically an electrochemical process. The synergistic coating system is still far the best for a wear application, however, and special fluoropolymers or dry are infuesed into the hardfacing.
--For titanium synergistic coating is called Canadize. For titanium application thickness is difficult to build up, so the normal application thickness is between 0.0002 and 0.0005 in.
--A classic application for Canadizing is titanium hardware for aircraft. Such components are anodized with an infusion to a thickness of 0.0002 - 0.0004 in. to prevent the titanium from seizing.
(Donates Satas, Coating Technology Handbook 2nd edition revised and expanded, page 308)
New Answer, better
Recognizing that titanium is highly susceptible to hydrogen pickup or embrittlement, metallurgical engineers at General Magnaplate created a series of coating processes that would preclude any hydrogen absorption. Called CANADIZE, these “synergistic”
coatings were used to prevent galling at the joints and in the drive shaft of titanium
core-sample drill tubes used in NASA’s exploration of the moon. The coatings also prevented
contamination of moon rock samples by titanium or other foreign materials.
CANADIZE coatings have been successfully employed to solve wear, friction, galling, seizing,
moisture and corrosion problems in a broad spectrum of applications involving titanium and its alloys.
The CANADIZE process begins with a proprietary cleaning process. The part is then enhanced to the desired thickness in a proprietary solution.
Through predetermined time and current control, a hard ceramic surface is formed. In instances where permanent dry lubrication is desired, one or more carefully selected engineering materials are infused into the surface, i.e. fluorocarbons, polymers, molybdenum disulfides, graphites, or combinations of these well known dry lubricants.
Titanium gland nuts used in aircraft are protected against freeze-up, abrasive wear and corrosion by a CANADIZE surface treatment. The dry-lubication of the coating also permits faster maintenance procedures.
(General Magnaplate, “Synergistic” Coatings for Titanium and
Titanium Alloys Prevent Hydrogen Absorption, p.1 )
5. Chromadizing (Surface th.)
Old Answer, better
Chromadizing (20:26 10.4.2011)
Improving paint adhesion an aluminum or aluminum alloys, mainly aircraft skins, by treament with a solution of chromic acid. Also called chromodizing or chromatizing.
(Pierre R. Roberge, Handbook of Corrosion Engineering, pg:958)
New Answer
chromadizing (chromodizing, chromatizing)
Applicaiton of a metal-conditioning solution of chromic acid to the surface of aluminum or aluminum alloys, used to improve adhesion of corrosion-resistant coating such as paints and resins.)
(Pohanish R., Glosary of Metalworking Terms, p. 94)
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