The effect of surface morphology on the friction of electrogalvanized sheet steel in forming processes
- Lawrence Berkeley Lab., CA (United States); California Univ., Berkeley, CA (United States). Dept. of Materials Science and Mineral Engineering
The effect in the drawbead simulator test were evaluated for a set of commercially coated steels and a set of laboratory coated steels with underlying surfaces produced by laser textured, shot blast, and electro-discharge textured rolls. In general, surfaces with higher roughness (Ra parameter) measured lower friction in the DBS tests. The requisite roughness amplitude necessary for low friction was moderated somewhat by having a more closely spaced roughness as described by the median wavelength, λm, of the power spectrum. This effect is due to interaction with the lubricant by the micro-roughness imparted by the galvanizing process. The lubricant tends to be retained better by the surfaces with the micro-roughness, thereby increasing the amount of elasto- and plasto-hydrodynamic support of the load. Other variables, such as large variations in thickness of the sheet can mask the effect of the surface by changing the actual distance of sliding contact during the DBS test. For tests where the amount of sliding is similar, the effect of roughness is significant. The friction measured for EG steels in the DBS test is dominated by deformation of the surface with plowing by the asperities of the tooling adding to that caused by the deformation. The size of the plow marks in the deformed surfaces corresponds to the roughness of the tooling and no significant evidence of wear particles was observed.
- Research Organization:
- Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC03-76SF00098
- OSTI ID:
- 10120745
- Report Number(s):
- LBL-35038; ON: DE94006294
- Resource Relation:
- Related Information: Thesis (Ph.D.)
- Country of Publication:
- United States
- Language:
- English
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