Method for rolling metal sheets with variable thickness

Patent metadata

Field	Value
Publication number	US-10758956-B2
Application number	US-201715421542-A
Country	US
Kind code	B2
Filing date	Feb 1, 2017
Priority date	Feb 4, 2016
Publication date	Sep 1, 2020
Grant date	Sep 1, 2020

Abstract

Described herein is a method for rolling metal sheets of variable thickness. The method makes it possible to impress, during rolling, any distribution of areas of increased thickness within a figure corresponding to the plane development of a motor-vehicle component prior to the pressing operation. Impression of the desired distribution of areas of increased thickness envisages simultaneous impression, during rolling, of a further distribution of areas of increased thickness, or compensation areas.

First claim

What is claimed is:

1. A method for rolling metal sheets with variable thickness, the method including:
determining a first distribution of areas having an increased thickness with respect to a nominal rolling thickness of the sheet, said first distribution of areas including one or more first areas, said sheet being a single metal sheet,
determining, for each first area of said first distribution, an increase of volume of material corresponding to a difference between a volume of material underlying each first area with the increased thickness assigned on the basis of said first distribution, and a volume of material underlying a corresponding area with the nominal rolling thickness,
determining a second distribution of areas having an increased thickness with respect to the nominal rolling thickness, wherein said second distribution of areas includes one or more second areas,
assigning, to each second area of said second distribution an increase of volume of material corresponding to a difference between a volume of material underlying each second area with the increased thickness assigned on the basis of said second distribution, and a volume of material underlying a corresponding area with the nominal rolling thickness, wherein an overall increase of volume of the one or more second areas of said second distribution is equal or higher to an overall increase of volume of the one or more first areas of said first distribution,
positioning the one or more first areas of said first distribution along said sheet in a desired position within a figure that corresponds to a plane development of a component of a motor-vehicle which is to undergo a pressing operation,
positioning the one or more second areas of said second distribution outside of said figure,
providing a pair of mill rolls having a surface relief that corresponds, developed on a plane, to the combination of the first and the second distribution of areas with increased thickness, and
rolling said metal sheet by means of said pair of mill rolls, wherein the one or more first areas of said first distribution are created with the one or more second areas of said second distribution.

2. The method according to claim 1 , wherein the increased thickness of the first areas of the first distribution is identical to the increased thickness of the second areas of the second distribution.

3. The method according to claim 1 , wherein the increased thickness of the first areas of the first distribution is different from the increased thickness of the second areas of the second distribution.

4. The method according to claim 3 , wherein the first areas with increased thickness of the first distribution and/or the second areas with increased thickness of the second distribution have an increased thickness different within the distribution itself.

5. The method according to claim 1 , wherein the first areas with increased thickness of the first distribution and the second areas with increased thickness of the second distribution are separate and distinct from each other.

6. The method according to claim 5 , wherein the first areas with increased thickness of the first distribution and the second areas with increased thickness of the second distribution are arranged and dimensioned so as to satisfy a criterion of constancy of an average flow speed of the rolled material across the sheet.

7. The method according to claim 1 , wherein the first distribution of areas with increased thickness and the second distribution of areas with increased thickness develop seamlessly with one another.

8. The method according to claim 7 , wherein the first distribution of areas with increased thickness and the second distribution of areas with increased thickness develop seamlessly in a single figure having a constant increased thickness, wherein the shape of said figure having an increased thickness and the difference between the increased rolling thickness and nominal rolling thickness are chosen so as to achieve a substantial constancy of the flow rate of rolled material across the sheet astride of interface areas between said figure with constant increased thickness and remaining sheet.

9. The method according to claim 1 , wherein a portion of the first areas with increased thickness of the first distribution and a portion of the second areas with increased thickness of the second distribution are separate and distinct to each other, while a remaining part of the first areas with increased thickness of the first distribution and a remaining part of the second areas with increased thickness of the second distribution extend seamlessly with each other.

10. The method according to claim 1 , wherein the first areas with increased thickness of the first distribution and the second areas with increased thickness of the second distribution are provided by alignment of recesses having complementary shapes on the surface of said pair of mill rolls.

11. The method of claim 1 , wherein the one or more first areas of said first distribution being created with the one or more second areas of said second distribution compensates for rolled material having a higher flow rate neighbouring the one or more first areas of said first distribution as compared to a slower flow rate of rolled material flowing into the one or more first areas of said first distribution, whereby said rolled material having the higher flow rate is configured to flow into the one or more second areas of said second distribution thereby slowing down and achieving a substantial constancy of a mean rate of overall flow of rolled material across the single metal sheet.

Assignees

• Fiat Ricerche

Inventors

• Colosseo Marco
• Bassan Daniele

Classifications

• B21H8/005 Primary

  Embossing sheets or rolls · CPC title

• B21B1/227

  Surface roughening or texturing · CPC title

• B21B1/38 Primary

  for rolling sheets of limited length, e.g. folded sheets, superimposed sheets, {pack rolling}(B21B1/40 takes precedence; folding sheets before, or separating layers after, rolling B21B47/00) · CPC title

• B21H8/02

  Rolls of special shape · CPC title

• B21B2205/02

  Tailored blanks · CPC title