Steel brackets are being cold bended 1

[demsha]

To All,

We purchase our products from steel supplier in a Asian country. One of the products we are buying is 105 degree angle bended brackets.
These bracket supposed to be hot bended. However, in few occasions we found that steel supplier conducting cold bend instead of hot bend.
can anyone tell me what would be the best method to check whether these brackets are cold or hot bend?

Thanks in advance

 

[EdStainless]

Inspect the process.
My guess is that you really want them warm bent.

What minimum temp do you require?
What is the alloy?

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Plymouth Tube

 

[metengr]

Hardness testing would be the best method to determine if the brackets are cold or hot formed.

 

[demsha]

Hi Metengr,

I agree with you. What type hardness meassurement? Micro or Macro? Where is in the bracket you would like to perform the hardness? At the bend location? I am planning conduct portbale hardness measurements on the plate using Microduor Hardness tester? What are the typical hardness values we should be looking for if the brackets are being cold bend and hot bend.

Thanks in advance

 

[metengr]

demsha;
The Microdur hardness tester is fine for this application. I would test the outside region of the bend and compare with the bracket material away from the bend. I would compare hardness readings between the two locations. For cold bending you will see higher hardness values (wider spread) in comparison to unaffected material. For hot bending, the hardness values would be closer in spread. I can't say how much difference because you did not provide the bracket composition. What you can do is test a bracket which has been confirmed as hot bent and compare with a bracket which has been confirmed as cold bent and actually compare the hardness differences.

 

[demsha]

Thanks Metengr:

The material is ASTM A572 grade 50. Do you know where can I get limits of cold and hot bending temperatures spread limits? Any standard you can refer?

Regards,
Demsha

 

[metengr]

Normally, for cold bending this would be 1100 deg F and below. For hot bending, this would be > 1100 deg F. The reference for these temperatures are based on bending of carbon steel tube/piping materials.

 

[demsha]

Hello Metengr:

Sorry I was referring to Hardness limits for cold and hot bending for the A 572 material.

Thanks

 

[metengr]

demsha;
As I mentioned previously, perform hardness testing on a cold formed bracket and on a hot formed bracket. This will allow you to evaluate hot versus cold bending and compare with bulk hardness (away from the bend).