Method of forming magnesium alloy sheets
A machine for asymmetric rolling of a work-piece includes pair of rollers disposed in an arrangement to apply opposing, asymmetric rolling forces to roll a work-piece therebetween, wherein a surface of the work-piece is rolled faster than an opposite surface of the work-piece; and an exit constraint die rigidly disposed adjacent an exit side of the pair of rollers so that, as the work-piece exits the pair of rollers, the work-piece contacts the exit constraint die to constrain curling of the work-piece.
1. A method of rolling a work-piece comprising the steps of:
a. heating a work-piece to a preselected rolling temperature;
b. using rollers, rolling the work-piece asymmetrically between a faster rate roller and a slower rate roller to form a tilted crystalline texture in the work-piece which curls in the direction of the slower rate roller; and
c. stripping the rolled work-piece from said slower rate roller, the stripping comprising stripping with a stripper blade positioned adjacent to the slower rate roller, and guiding the work-piece with a guide surface toward and into an exit constraint slot, the exit constraint slot being distanced from the stripper blade in the direction of movement of the work-piece and the guide surface being positioned between the stripper blade and the exit constraint slot, the space between the surface of the faster rate roller and the exit constraint slot being open, and passing the rolled, stripped work-piece through the exit constraint slot to limit curling of the rolled work-piece and maintain the tilted crystalline texture as the rolled work-piece exits said rolling step.
2. A method in accordance with claim 1 wherein the rolling step is carried out isothermally.
3. A method in accordance with claim 1 wherein the constraining step is carried out isothermally.
4. The method of claim 1 , wherein the guiding step comprises contacting the work-piece with a low friction guide surface.
5. A method of rolling a metal body comprising magnesium, the method comprising the steps of:
a. heating the metal body to a preselected rolling temperature in the range of 130° C. to 350° C.;
b. rolling the metal body asymmetrically between a faster rate roller and a slower rate roller to form a tilted crystalline texture in the metal body which curls in the direction of the slower rate roller; and
c. stripping the rolled work-piece from said slower rate roller, the stripping comprising stripping with a stripper blade positioned adjacent to the slower rate roller, and guiding the work-piece with a guide surface toward and into an exit constraint slot, the exit constraint slot being distanced from the stripper blade in the direction of movement of the work-piece and the guide surface being positioned between the stripper blade and the exit constraint slot, the space between the surface of the faster rate roller and the exit constraint slot being open, and passing the rolled, stripped work-piece through the exit constraint slot to limit curling of the rolled work-piece and maintain the tilted crystalline texture as the rolled work-piece exits said rolling step.
6. A method in accordance with claim 5 wherein the rolling step is carried out isothermally.
7. A method in accordance with claim 5 wherein the constraining step is carried out isothermally.
8. The method of claim 5 , wherein the guiding step comprises contacting the work-piece with a low friction guide surface.