In low Carbon steel does compression increase grain size during anneal

[BatchHand]

First Post NOOB!
As a rule of thumb can grain size be increased during batch annealing by point loading the material and adding compressive load? i.e. if I have 200 Tons being annealed in a stacked batch situation and only 60% of the bottom surface is supported, will the points that see all the load have different grain growth?

 

[swall]

Are we talking about steel or non ferrous metal?

 

[BatchHand]

Yes, steel. ASTM A1004 or A1008.

 

[swall]

Oops--I forgot that you said steel right in the title. What is the annealing temperature?

 

[BatchHand]

Looking for a core of 1250F, hot spot around 1280-1300F. To give some added information. This is flat steel strip, coiled. I'm trying to make a possible correlation of edge discontinuous yielding to larger grain size in spots that carried all the weight during annealing thus having lower yield strength. I already have data to prove that the more weight applied the more discontinuous yielding I see on edges. The body of the material has the same mechanicals regardless of load applied. So why more discontinuous yielding on edges? So that is the rest of the story.

 

[TVP]

Your theory may be correct. It is well-known that grain size after annealing is very much dependent upon the strain and strain distribution within the material, and that there is a critical amount of strain below which considerable grain growth occurs. This critical amount is also a function of temperature. I have seen some curves for aluminum alloys published, but can't think of any for steel right off the top of my head. Are you annealing hot-rolled or cold-rolled coils?

 

[BatchHand]

Cold rolled coils. I have been looking for some papers and/or curves showing this in steel. If anyone knows of any I would really appricate any info.

 

[swall]

You should try to find a copy of Leonard Samuels book, "Light Microsscopy of Carbon Steels". He shows evidence of sporadic large grains after a subcritical anneal of material that has been worked.