tailieunhanh - Standard Handbook of Machine Design P8

CHAPTER 6 WEAR Kenneth C. Ludema Professor of Mechanical Engineering Department of Mechanical Engineering and Applied Mechanics The University of Michigan Ann Arbor, Michigan GENERAL PRINCIPLES IN DESIGN FOR WEAR RESISTANCE / STEPS IN DESIGN FOR WEAR LIFE WITHOUT SELECTING MATERIALS / WEAR EQUATIONS / STEPS IN SELECTING MATERIALS FOR WEAR RESISTANCE / MATERIAL-SELECTION PROCEDURE / REFERENCES / BIBLIOGRAPHY / There is no shorthand method of designing machinery for a specified wear life. Thus a step-by-step method is given for designers to follow. The method begins with an examination of worn parts. | CHAPTER 6 WEAR Kenneth C. Ludema Professor of Mechanical Engineering Department of Mechanical Engineering and Applied Mechanics The University of Michigan Ann Arbor Michigan GENERAL PRINCIPLES IN DESIGN FOR WEAR RESISTANCE I STEPS IN DESIGN FOR WEAR LIFE WITHOUT SELECTING MATERIALS I WEAR EQUATIONS I STEPS IN SELECTING MATERIALS FOR WEAR RESISTANCE I MATERIAL-SELECTION PROCEDURE REFERENCES BIBLIOGRAPHY There is no shorthand method of designing machinery for a specified wear life. Thus a step-by-step method is given for designers to follow. The method begins with an examination of worn parts of the type to be improved. The next step is an estimate of stresses temperatures and likely conditions of operation of the redesigned machinery. Material testing for wear resistance is discussed and finally a procedure is given for selecting materials for wear resistance. GENERAL PRINCIPLES IN DESIGN FOR WEAR RESISTANCE The wear life of mechanical components is affected by nearly as many variables as human life. Wearing surfaces are composed of substrate material oxide absorbed gas and dirt. They respond to their environment method of manufacture and conditions of operation. They suffer acute and or progressive degeneration and they can often be partially rehabilitated by either a change in operating conditions or some intrusive action. The range of wearing components and devices is endless including animal teeth and joints cams piston rings tires roads brakes dirt seals liquid seals gas seals belts floors shoes fabrics electrical contacts disks and tapes tape heads printer heads tractor tracks cannon barrels rolling mills dies sheet products forgings ore crushers conveyors nuclear machinery home appliances sleeve bearings rollingelement bearings door hinges zippers drills saws razor blades pump impellers valve seats pipe bends stirring paddles plastic molding screws and dies and erasers. There is not a single universal .