Aluminum bar and production method thereof

Abstract

A production method of an aluminum bar includes a surface pressing step of pressing a surface of an aluminum bar with pressure rollers. A pressing force of the pressure rollers in the surface processing step is set within a range of 1.5 Fc to 4.0 Fc, where, in a relationship between a pressing force of the pressure rollers to the aluminum bar and a straightness of the aluminum bar, when a boundary point at which a section where the straightness of the aluminum bar improves as the pressing force of the pressure rollers increases shifts to a section where the straightness does not change as the pressing force of the pressure rollers increases is a straightness saturation point, and the pressing force of the pressure rollers at the straightness saturation point is “Fc”.

1 . A production method of an aluminum bar, comprising:
 a surface pressing step of pressing a surface of an aluminum bar with pressure rollers,   wherein a pressing force of the pressure rollers in the surface processing step is set within a range of 1.5 Fc to 4.0 Fc,   where, in a relationship between a pressing force of the pressure rollers to the aluminum bar and a straightness of the aluminum bar, when a boundary point at which a section where the straightness of the aluminum bar improves as the pressing force of the pressure rollers increases shifts to a section where the straightness does not change as the pressing force of the pressure rollers increases is a straightness saturation point, and the pressing force of the pressure rollers at the straightness saturation point is “Fc”.   
     
     
         2 . The production method of an aluminum bar as recited in  claim 1 ,
 wherein a pair of straightening rolls are used as the pressure rollers, and   wherein a straightening step for straightening an aluminum bar by passing the aluminum bar between the pair of rotating straightening rolls is also used as the surface pressing step.   
     
     
         3 . The production method of an aluminum bar as recited in  claim 1 , further comprising a peeling step of cutting and removing an outer peripheral surface of the aluminum bar before performing the surface pressing step. 
     
     
         4 . The production method of an aluminum bar as recited in  claim 1 , wherein the aluminum bar is an aluminum member to be used as a forging blank. 
     
     
         5 . An aluminum bar produced by the production method as recited in  claim 1 ,
 wherein, among two points set on a load curve showing a relationship between a cutting level and a load length for a contour curve on a surface of the aluminum bar, when two points in which an interval of the load length becomes 60% of the entire length of the load length are a pair of measuring points, a minimum value of a slope of a straight line passing the pair of measuring points is 0.5 or less.