Lecture 4b - Surface and Tribology

Lecture 4b - Surface and Tribology - Surface...

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Unformatted text preview: Surface Characteristics and Tribology Surface Characteristics and Tribology Lecture 4.b ISE 2204 – Introduction to Manufacturing Processes Dr. Jaime Camelio February 12 th , 2009 Surface Properties Surface Structure Surface Roughness Tribology Friction Wear Lubrication Surface Treatment ISE 2204 – Introduction to Manufacturing Processes – Spring 2009 Outline Outline Produced with a Trial Version of PDF Annotator - www.PDFAnnotator.com Although bulk material determines the overall mechanical properties, the surface affects: ◦ Friction and wear ◦ Effectiveness of lubricants ◦ Appearance Appearance ◦ Fatigue crack initiation ◦ Corrosion The manufacturing process determines many surface properties ISE 2204 – Introduction to Manufacturing Processes – Spring 2009 Surface Properties Surface Properties Schematic illustration of the cross-section of the surface structure of metals. The thickness of the individual layers depends on processing conditions and the environment ISE 2204 – Introduction to Manufacturing Processes – Spring 2009 conditions and the environment. Source : After E. Rabinowicz and B. Bhushan . Surface Structure Surface Structure Metal substrate ◦ Bulk material properties depend on composition and processing. Work hardened layer ◦ Deformed during processing -- may have recrystallized Beilby or amorphous layer Beilby or amorphous layer ◦ Region that melted and then rapidly solidified -- not always present Oxide layer ◦ Can be protective or non protective -- affects friction and wear Adsorbed gas Contaminants ISE 2204 – Introduction to Manufacturing Processes – Spring 2009 Surface Structure Surface Structure Flaws ◦ Random irregularities such as cracks, depressions, etc. Lay ◦ Direction of the predominant surface pattern Waviness ◦ Long wavelength deviations Waviness width Waviness height Roughness ◦ Short wavelength deviations superimposed on the waviness ISE 2204 – Introduction to Manufacturing Processes – Spring 2009 Surface Texture and Roughness Surface Texture and Roughness AA (arithmetic average) or CLA (center line average) roughness, R a (y a are absolute values) Root mean square roughness, Rq Rq gives more weight to large deviations ISE 2204 – Introduction to Manufacturing Processes – Spring 2009 Surface Roughness Methods Surface Roughness Methods ISE 2204 – Introduction to Manufacturing Processes – Spring 2009 Surface Texture Surface Texture Standard terminology and symbols used to describe surface finish....
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This note was uploaded on 02/20/2010 for the course ISE 2204 taught by Professor Rhsturges during the Spring '08 term at Virginia Tech.

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Lecture 4b - Surface and Tribology - Surface...

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