Part4 Answer short questions : 1. Name five methods of producing metal powders:
ID: 1717224 • Letter: P
Question
Part4
Answer short questions :
1. Name five methods of producing metal powders: Atomisation Reduction Electrolytic deposition Carbonyls Communition Mechanical alloying Precipitation Machining Vapour condensation
2. Name five surface treatment methods used to increase surface hardness and/or fatigue life: Shot peening Water jet peening Laser peening Roller burnishing Explosive hardening Cladding Mechanical plating Case hardening Vapour deposition Ion implantation Diffusion coating Electroplating Anodizing
Explanation / Answer
1Answer
atomisation reduction is a process in which molten metal is disintigrated into small droplets and are allowed or caused to solidify out of contact with each other. the most common method of preparing the droplets is to allow a stream of molten metals to fall vertically into a chamber where it is broken by high pressure jets of liguid or gas.
in Electrolytic deposition method the process is designed in such a manner that metals of high puriy are precipitated from aqueous solution on the cathode of an electrolytc cell. this is mainly used for production of powders of zinc,tin,copper silver etc.
Crrbonyl: metals powder are formed by forming carbonyls like Iron carbonyls,nickel carbonyls etc by reacting nickel or iron with carbon mono-ocide.
Communition ia a method to produce metal powder by application of mechanocal mills.
2). answer
shot peening is a process which is employed to inhance the fatigue strength of components which are subjected to high alternating stress. in this method smalll spherical odies called shots are bombarded on the surface such that each shot acts like peening hammer
Laser peening is a process used to impart residual stresses in the material in order to increase the resistance of the material to surface related failureslike fatigue,freeting and stress corrossion.
water jet peening isa technique in which residual stresses are generted by causing cavitation at the boundry between high speed water from water jet peening nozzle and the surroundin water which creates plastic deformation using shock pressure from the collapsing bubbles to change surface condition
Roler Burnishing is cold working process employed to induce compressive residual stres and improve surface roughness qualities. in this method a hard roller is pressed upon the part which is to be processed. this part moves with a constant velocity,therefore producing a consistant finins across thesurface