Metal deforming – Process – 'rolling'
Patent
1999-11-22
2000-10-17
Butler, Rodney A.
Metal deforming
Process
'rolling'
722525, B21B 3920
Patent
active
061314323
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
This invention relates to a process for manufacturing a metal sheet, and more particularly to a process for cold rolling a sheet of steel, aluminum, an aluminum alloy, copper, a copper alloy, or another metallic material for manufacturing, among others, a metal foil having a thickness of 0.2 mm or less. The metal foil will be used as a material for electronic devices, a heat resisting material, a material for interior decoration, a material for automobile parts, or a material for use in other fields of industry.
BACKGROUND ART
If a rolled material has its thickness reduced to a critical level, a further reduction of its thickness promotes the elastic deformation of work rolls and makes any further rolling impossible. This critical thickness is called the minimum rollable thickness, and is defined by the following equation: .mu.=coefficient of friction between the rolls and the rolled material, km=mean deformation resistance of the rolled material (kgf/mm.sup.2), and E=Young's modulus of the rolls (kgf/mm.sup.2).
The minimum rollable thickness resulting from the mutual contact, or kissing of the upper and lower rolls at the opposite ends of the roll barrels is defined by the equation (2): /b.sup.2).multidot.(B+b)/(B-b), L'=projected contact length (mm), B=barrel length of the rolls (mm), b=sheet breadth (mm), P=rolling force (kgf), .nu.=Poisson's ratio of the rolls. (See, for example, The Third Edition of Iron & Steel Handbook, III (1) Fundamentals of Rolling-Steel Sheets, Maruzen Publishing Co., page 42.)
According to the equation (1), the minimum rollable thickness is in direct proportion to the roll diameter, while it is in inverse proportion to the Young's modulus of the rolls according to the equations (1) and (2), and it is, therefore, usual practice to employ work rolls having a small diameter and a high Young's modulus for rolling a metal foil to make the minimum rollable thickness smaller, as compared with the rolls which are usually employed for cold rolling (to make a sheet having a thickness of, say, 0.2 mm or larger). Examples of the work rolls having a high Young's modulus are ceramic and ultrahard alloy rolls. (See, for example, "Plasticity and Working", Vol. 2, No. 9, page 325 to 334, or Vol. 9, No. 84, page 20 to 29.)
The rolling force per unit width, p (kgf/mm), is expressed by the following equation: (mm) as expressed by the following Hitchcock's equation: on the inlet side or before rolls, hi-thickness on the outlet side or therafter, h.sub.0) (mm). (See, for example, The Third Edition of Iron & Steel Handbook, III (1) Fundamentals of Rolling-Steel Sheets, Maruzen Publishing Co., page 41.)
As C in the equation (4) is the decreasing function of E, the rolls having a higher Young's modulus E have a smaller flattened radius R', and are also less bent. If the rolls are not satisfactorily flattened or bent for absorbing the factors having an adverse effect on the shape of a product (e.g. lack of uniformity in rolling pressure along the sheet breadth, and its variation with time), it is likely that a product having a defective shape may be obtained. Therefore, Japanese Patent Application Laid-Open No. Hei 1-197004(1989), for example, proposes the use of work rolls having a Young's modulus of 31,000 to 54,000 kgf/mm.sup.2 for the last pass in the manufacture of a metal foil by continuous rolling.
The use of rolls having an upper limit on their Young's modulus as proposed is, however, a disadvantage when it is desirable to decrease the number of passes between rolls and thereby achieve an improved rolling efficiency. The decrease in number of passes necessarily calls for an increase in reduction of thickness per pass and thereby an elevated rolling pressure.
As it is obvious from the equation (2) that the minimum rollable thickness, h.sub.min, resulting from the kissing of rolls is in direct proportion to the rolling pressure and in inverse proportion to the Young's modulus of the rolls, it is limited by the maximum Young's modulus of the rolls if the rolling pressure is rais
REFERENCES:
patent: 4332192 (1982-06-01), Joutsjoki
patent: 4591259 (1986-05-01), Kuo et al.
patent: 4597326 (1986-07-01), Tanpani
patent: 4991499 (1991-02-01), Kusters
patent: 5706690 (1998-01-01), Connolly
patent: 5746081 (1998-05-01), Klamma, et al.
Kamimaru Akinobu
Matsubara Tsutomu
Miyata Takashi
Saisu Masaharu
Yamaguchi Yasuhiro
Butler Rodney A.
Kawasaki Steel Corporation
LandOfFree
Method of manufacturing metal foil does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method of manufacturing metal foil, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method of manufacturing metal foil will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-457947