Stock material or miscellaneous articles – All metal or with adjacent metals – Having variation in thickness
Patent
1993-05-03
1994-10-25
Zimmerman, John
Stock material or miscellaneous articles
All metal or with adjacent metals
Having variation in thickness
428687, 2989532, B21B 2700, B21D 5300
Patent
active
053587944
DESCRIPTION:
BRIEF SUMMARY
DESCRIPTION
1. Technical Field
The present invention relates to a steel strip having excellent painting sharpness and press moldability and a rolling dull roll for use in the production of said steel strip.
2. Background Art
The surface of a cold-rolled steel strip to be worked is generally subjected to dull finishing for the purpose of facilitating press molding, because a working lubricant is reserved during press working in an uneven portion formed on the surface of a steel strip, which serves to reduce the friction between the mold and the steel strip and, at the same time, prevent the occurrence of seizure.
Press moldability has been studied from the viewpoint of an iron strip as material and molding technique. However, with an increase in the precision and complexity of products, there is an ever-increasing demand for more sophisticated and diversified steel strip properties.
On the other hand, armored steel strips for the bodies of automobiles, domestic appliances, etc. are subjected to paint finishing for the purpose of imparting an aesthetic sense to the steel strips. In this case, it is required that no deterioration in the aesthetic sense due to irregular reflection occur, that is, the so-called "painting sharpness" should be excellent.
Examples of the above-described prior art include one disclosed in Japanese Unexamined Patent Publication (Kokai) No. 62-168602 entitled "Steel Strips for Painting and Method for Producing the Same". In the steel strip proposed in this document, the center line average roughness, Ra, on the surface thereof is in the range of from 0.3 to 2.0 .mu.m, and the microscopic morphology constituting the surface roughness comprises a trapezoidal crest portion having a flat crest face and a grooved root portion formed so as to surround the whole or part of the periphery of the crest portion and an intermediate flat portion formed in such a manner that it is located between the crest portions and outside the root portions and has a height higher than the bottom of the root portion and lower than or equal to the crest of the crest portion; said configuration satisfying a requirement represented by the following formulae: 0.85.ltoreq.Sm.ltoreq.1.7, Sm-D<280 (.mu.m), 30.ltoreq.d.sub.0 .ltoreq.500 (.mu.m) and 20.ltoreq..eta..ltoreq.85 (%) wherein Sm represents the average center line distance between adjacent crest portions, D represents the average diameter of the outer periphery of the root portion, d.sub.0 represents the average diameter of the flat crest face of the crest portion and .eta. (%) represents the proportion of the sum of the area of the flat crest face and the area of the flat face of the intermediate flat portion to the total area.
Respective profiles of the above-described conventional roll and steel strip surfaces are shown in FIGS. 1 and 2, wherein diameter of the periphery of a root portion 11 of a steel strip surface; of the steel strip surface; depth defined as a distance from an intermediate flat portion 9 on the steel strip surface to the bottom of the root portion 11; portion 9 to the flat crest face 8 of the crest portion 10 on the steel strip surface. surface=the average center distance between adjacent crest portion 10 on the surface of the steel strip surface; .eta..sub.1, of the flat crest face 8 of the crest portion 10 and the proportion of area, .eta..sub.2, of the intermediate flat portion 9).
The present status with respect to press moldability is that, in temper rolling conducted for the purpose of finally regulating the roughness of a steel strip, the roughness is transferred to the surface of a steel strip by using a work roll subjected to dulling by means of shot blasting, electric discharge, laser beam or the like. Further, in actual press molding, sole use of mechanical properties (r value, E1 value, etc.) of the steel strip adopted in the art is unsatisfactory as evaluation criteria of press moldability, and the surface roughness of the steel strip, the lubricating oil, etc. also have a great influence on press moldability thereof.
F
REFERENCES:
patent: 3775261 (1973-11-01), Rieth et al.
patent: 4322600 (1982-03-01), Crahay
patent: 4329562 (1982-05-01), Crahay et al.
patent: 4462600 (1984-07-01), Crahay
patent: 4783378 (1988-11-01), Wakui et al.
patent: 4795681 (1989-01-01), Furukawa et al.
patent: 4798772 (1989-01-01), Furukawa
patent: 4806731 (1989-02-01), Bragard et al.
patent: 4978583 (1990-12-01), Wakui et al.
Hamamoto Yasuo
Kawamoto Takaharu
Nawata Yasutaka
Shiozawa Shuichi
Toyota Hiromi
Nippon Steel Corporation
Zimmerman John
LandOfFree
Steel strip and method for producing rolling dull roll does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Steel strip and method for producing rolling dull roll, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Steel strip and method for producing rolling dull roll will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-134210