When sheetmetal is bend perpendicular to rolling direction grain rearranges.
Grain direction in sheet aluminum.
Two rollers compressing the hot metal cause the polycrystalline material to elongate in the direction of rolling.
A plate s grains run parallel to the rolling direction.
I m sure that 7075 sheet is made the same as 6061 with grain running lengthwise.
The grain direction is established during the metal rolling process.
This has to do with the sheet grain direction.
By default in my testing the bounding box aligns itself with the longest straight side.
During sheet metal processing rolling operation material grains are arranged in the direction of rolling.
The grain direction of the metal also contributes to the amount of springback that occurs in a bending operation.
In addition to the new bounding box sketch there is a new option in the property manager for the flat pattern feature.
You ll now see that your flat pattern is generated based on one edge oriented parallel to the angled edge and the other obviously perpendicular to that in drawing the rectangle.
Only concern would be a rough grain can cause a stress riser if not polished out if a bending load is applied perpendicular to the grain.
Strength will be the same in all directions.
Once the crystallites are elongated they appear as the.
7075 is very notch sensitive.
The grain direction is in the rolling direction of the sheet as it was being manufactured.
You can define a grain direction to use when calculating the bounding box for sheet metal parts.
The software determines the smallest rectangle bounding box that aligns with the grain direction to fit the flat pattern.
Bending with the grain gives a different result than bending against it.
The crystalline lattice structures form during the cooling of the metal from its molten state and are held together by thin layers of amorphous solid.
As a general rule the grain line must run perpendicular to the bend to avoid the potential for cracking or fracture.
Where does grain direction come from.
Whereas bending parallel to rolling direction can lead to cracks because of destruction in grain structure.
Applying this to metal bending be it plate bending press braking or any other type of metal forming consideration must be given to the grain direction before any process is carried out.
That has negligible impact on part strength.
