hot / cold rolled crystalline structure 4

[Eggbert]

Which has the largest crystal structure between hot or cold rolled metals, especially Brass and Aluminium, and why?
Also, which of the two is used most for stamping parts from?

I work for a manufacturer of abrasives, one of which is a polishing product which, on some non-ferrous stampings, appears to drag the surface creating occasional teardrop shaped pits. This we can only put down to the crystal structure of the surface but, as end-users rarely know what they are working with, we need to know whether hot or cold rolled is to blame so we can offer the best recommendations to customers.

Thanks for the help.

 

[CoryPad]

Hot rolled metals have larger crystals (grains) due to recrystallization and grain growth.

Both are used quite often for stamping parts.

Abrasive embedment and metal surface damage are functions of metal strength, hardness and stiffness, abrasive stiffness and hardness, presence or absence of lubrication, and pressure applied to the surface.

Regards,

Cory

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[alexit]

Hot-rolled is typically harder than cold-rolled too, ranging above and below 70 Rb typically.

 

[metengr]

alexit;
Your post above needs to be edited - cold rolled metals are typically harder in comparison to hot rolled metals. Cold rolling, which is performed below the recrystallization temperature of the metal, typically results in a phenomenon called "work hardening" that increases the hardness of the metal.

 

[alexit]

Metengr;

Thank you! I write too faster sometimes...

Make post "Cold-rolled is typically harder than hot-rolled..."

 

[stanweld]

Stamping parts is normally done on cold rolled and recrystallized annealed materials. The recrystallization temperature affects hardness. Normally you would purchase to a specific temper (hardness)range depending on severity of drawing cold work induced during stamping for the particular product. Specific cold reduction tempers(1/4 hard, 1/2 hard) are also specified for stamped part materials depending on the desired mechanical properties of the finished part and the severity of draw.

 

[swall]

Here's my shot at it. Cold rolled is generally harder than hot rolled, with drawing quality steels being the notable exception, as stanweld points out.