Micromechanisms of Friction in Electrogalvanized Sheet Steel with Emphasis on the Role of Texture (Thesis)

Technical Report · Sat Dec 01 04:00:00 EST 1990

DOI:https://doi.org/10.2172/6004401· OSTI ID:6004401

Shaffer, Steven Jay ^[1]

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1. Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States); University of California, Berkeley, CA (United States)

The role of texture (preferred crystallographic orientation) of the zinc coating in friction of electrogalvanized steels is investigated. Samples of sharp (1) basal (fine grained and course grained), (2) low angle pyramid, (3) high angle pyramid, and, achieved through the addition of cadmium to the electrolyte, (4) prism textures, which were produced via laboratory electrodeposition, were friction tested using both a drawbead simulator (DBS) and a one-sided straight stripdraw test. It was found that the initial texture of the samples did not influence friction through the zinc's anisotropic response to loading. However the fine grained basal samples did exhibit unusually high friction, which was attributed to a rapid increase in contact area fraction due to easy shearing of the individual zinc crystallites. In an opposite manner, the prism textured samples exhibited exceptionally low friction as a result of low contact area fraction, which was attributed to a combination of higher hardness and a rougher topography. It is concluded that those factors within the coating which dictate contact area fraction control friction. The two most prominent are surface roughness and hardness. It was found through pole figure measurements that large changes in the texture of the zinc, restricted to a depth of about 1 {mu}m, take place as a result of friction testing. Progression toward a common texture is the result of plastic deformation, with strong evidence of recrystallization. Calculations of resolved shear stresses for slip on the basal system corroborated this through predicted difficulty in deformation for orientations whose basal poles lie along a trace perpendicular to the macroscopic shearing direction. Finally, techniques for rapid in-sheet-plane texture measurement and for deconvolution of textures as a function of depth and contact area fraction are proposed.

• Research Organization: Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
• Sponsoring Organization: USDOE Office of Energy Research (ER); Ford Motor Company; Rouge Steel Company; LTV Steel Company
• DOE Contract Number: AC03-76SF00098
• OSTI ID: 6004401
• Report Number(s): LBL--29960; ON: DE91009113
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360103* -- Metals & Alloys-- Mechanical Properties
ALLOYS
COATINGS
ELEMENTS
FRICTION
IRON ALLOYS
IRON BASE ALLOYS
MECHANICAL PROPERTIES
METALS
RECRYSTALLIZATION
ROUGHNESS
STEELS
SURFACE PROPERTIES
TEXTURE
ZINC