Hardenability Lab
Metallographic Observation
Metallographic Observation
Group # 26
Group # 26 Me 230: Control of Properties of Materials
Me 230: Control of Properties of Materials
Department of Mechanical and Mechatronics Engineering
University of Waterloo
Instructor: Caroline Hanson
Date: 4, April, 2013
Department of Mechanical and Mechatronics Engineering
University of Waterloo
Instructor: Caroline Hanson
Date: 4, April, 2013
Introduction
Engineers study the properties of materials to help choose the right kind of materials for a specific application. After material is chosen, one way to improve upon its properties is to apply heat treatment processes. A heat treatment involves rapid heating or cooling of a metal or alloy at extreme temperatures. For decades, engineers obtain desirable strength and hardness by austenitizing the steel and then quenching it to form martensitic structure. After fully converting to martensitic, steels are tempered to achieve right amount of ductility and hardness. The ability to form martensite on quenching is called hardenability. Both hardness and hardenability solely depends on the composition of metal and the geometry of specimen.
In this experiment, the specimen (X-10) is heated above the austenitizing temperature and then quenched in the cold water to form martensitic structure. The hardness is then measured at intervals from quenched end to determine the extent of increased hardness. Steels that have good hardenability will show higher hardness value throughout the intervals than those having poor hardenability. Also, good hardenable steels tends to have curves that are flatter compare to poor hardenble steels.
The presence of certain alloying elements shift the time temperature transformation curve and allows martensite to form at a lower cooling rate. In the hardenability tests, the effects of these elements increases the hardness values as distance from quenched end increases. In many
Metallographic Observation
Group # 26
Group # 26 Me 230: Control of Properties of Materials
Me 230: Control of Properties of Materials
Department of Mechanical and Mechatronics Engineering
University of Waterloo
Instructor: Caroline Hanson
Date: 4, April, 2013
Department of Mechanical and Mechatronics Engineering
University of Waterloo
Instructor: Caroline Hanson
Date: 4, April, 2013
Introduction
Engineers study the properties of materials to help choose the right kind of materials for a specific application. After material is chosen, one way to improve upon its properties is to apply heat treatment processes. A heat treatment involves rapid heating or cooling of a metal or alloy at extreme temperatures. For decades, engineers obtain desirable strength and hardness by austenitizing the steel and then quenching it to form martensitic structure. After fully converting to martensitic, steels are tempered to achieve right amount of ductility and hardness. The ability to form martensite on quenching is called hardenability. Both hardness and hardenability solely depends on the composition of metal and the geometry of specimen.
In this experiment, the specimen (X-10) is heated above the austenitizing temperature and then quenched in the cold water to form martensitic structure. The hardness is then measured at intervals from quenched end to determine the extent of increased hardness. Steels that have good hardenability will show higher hardness value throughout the intervals than those having poor hardenability. Also, good hardenable steels tends to have curves that are flatter compare to poor hardenble steels.
The presence of certain alloying elements shift the time temperature transformation curve and allows martensite to form at a lower cooling rate. In the hardenability tests, the effects of these elements increases the hardness values as distance from quenched end increases. In many
References: 1) "Heat Treatments: Introduction." Heat Treatments: Introduction. N.p., n.d. Web. 24 Feb. 2013. http://www.efunda.com/processes/heat_treat/introduction/heat_treatments.cfm 2) ME 230 – Control of Properties of Materials Laboratory Manual, Department of Mechanical and Mechatronics Engineering, University of Waterloo, April 2013. 3) D.R. Askeland and P.P. Phulé, The Science and Engineering of Materials, 5th ed., Thomson Canada Ltd., Toronto, ON, 2006. Appendix