Refine Your Search

Search Results

Viewing 1 to 5 of 5
Technical Paper

Influence of Dry Film Lubricant on Press Formability of Steel Sheets

2001-03-05
2001-01-0080
We have developed a new dry film lubricant with friction properties superior to those of conventional dry film lubricants by optimizing the glass transition temperature of the binder resin and adding polyethylene wax and inorganic lubricants. As described in this paper, the new dry film lubricant was applied as a coating on hot rolled steel sheets and galvannealed steel sheets in thicknesses ranging from 1.5 to 2.5 μm. The influence of the dry film lubricant and a rust preventive lubricant oil on the press formability of these steel sheets was investigated. A comparison of the press formability of high strength steel sheets with the dry film lubricant and sheets with the rust preventive lubricating oil suggested that application of the new dry film lubricant expands the use of high strength steel sheets and galvannealed steel sheets in automotive body panels.
Technical Paper

Evaluation of the Corrosion Rate of Zn Coated Steel Sheets for Automotive Body Use

1997-02-24
971003
The corrosion mechanism of zinc coated steel sheets in automotive bodies was studied in field vehicle tests and several types of accelerated tests. Perforation corrosion starts in unpainted areas of lapped parts, and proceeds in the following steps: i) galvanic protection by the Zn coating, ii) protection by corrosion products, and iii) corrosion of the steel substrate and perforation. Although the corrosion processes were the same in all the cases tested, the corrosion rate depended significantly on the environment, such as atmospheric exposure conditions and the part of the automotive body. In accelerated corrosion environments, Zn coating is largely ineffective against perforation corrosion because galvanic protection and protection by corrosion products cannot be maintained over the long term.
Technical Paper

Corrosion Behavior of a Vehicle Submitted in Service in Subtropical Marine Environment of Okinawa Island for Eight Years

1996-02-01
960021
A passenger vehicle in the subtropical marine environment of Okinawa Island for eight years was submitted for corrosion investigation.The precoated sheet steels such as Zn-Ni and Zn-Fe showed excellent corrosion resistance in the door hem flange and a scribed outer panel, compared to cold rolled steel. Cosmetic corrosion of a North America vehicle was more severe than that of a Okinawa vehicle, but a similar corrosion rate for perforation was shown in door hem flange. Basic zinc chloride and β-FeOOH were observed by using micro X-ray diffraction method in the initial stage of corrosion, and then these changed to ZnO and α-FeOOH, Fe304.
Technical Paper

Corrosion Behavior of Organic Composite Coated Steel Sheet

1993-10-01
932362
Organic composite coated steel sheets retain their excellent corrosion resistance during cyclic corrosion tests (CCT). To clarify the corrosion behavior of these sheets during CCT, variations in corrosion products and coating components were examined. Moreover, the contribution of the corrosion products, organic composite coating, and chromate film to corrosion resistance was examined by AC impedance measurements. Formation of crystalline ZnCl2·4Zn(OH)2 and amorphous zinc carbonate were detected by X-ray diffraction (XRD) and Fourier transformation infrared spectroscopy (FT-IR). Crystalline ZnCl2·4Zn(OH)2 is formed during CCT on and under the organic composite coating. The corrosion products formed on the coating contain silicates from the silica in the organic composite coating. Consequently, the contents of zinc and silica in the coating decrease, while nickel and chromium in the chromate film and carbon in the coating remain constant during CCT.
Technical Paper

Properties of Precoated Galvannealed Steel Sheets for Lead-Free Automotive Fuel Tank Use

2000-03-06
2000-01-0307
The goal of this study was to identify a pre-coated steel sheet that will satisfy press formability, seam weldability, spot weldability, brazing property, external corrosion resistance and internal fuel resistance. We established an experimental method for anti-fuel resistance measurement by applying synthetic spoiled gasoline by investigating the composition of spoiled gasoline and corrosion products in the fuel tank, which was collected in North America after 160,000 kilometers' running. Newly developed lead-free pre-coated steel sheet shows excellent anti-fuel corrosion resistance in comparison with that of usual terne coated steel sheet according to this method.
X