Transversal Charpy test on 1026 tube before and after stress relieve 1

[JPGraphX]

Hi!

I would like to know if a stress relieve should affect the result of a charpy test on tubing. (my tube is 1026 11" OD x 2" wall).

I've sent my tube to a firm for a charpy test on hot rolled 1026 tube. My results were 12 ft·lb/in longitudinal and 14 ft·lb/in transversal.

I need to get a better charpy test with that material, is it something possible?

Anyone have data or experiences about that? I've searched a lot through internet but didn't found anything.


Thanks,
JP

 

[TVP]

Normalizing will likely refine the grain structure and result in improved fracture toughness (Charpy test). You can do a Google search for normalizing heat treatment steel for more information.

 

[JPGraphX]

That is what I think, but I would like to know, how much. 5%, 20%, 35% ? That's a huge difference.

Thanks,
JP

 

[metengr]

Normalizing will help but other factors are involved, like sulfur content. Look at this paper referenced regarding carbon steel weld metal. It does give some relative change between as welded and normalize heat treatment for C-Mn steel weldments (page 65 of the paper).

http://www.scielo.br/pdf/jbsmse/v26n1/a11v26n1

 

[blacksmith37]

"AISI 1026" defines almost no metallurgical properties. try ASTM A 334.

 

[weldstan]

What is the test temperature? Normalizing, Normalizing and Tempering, Double Normalizing and Temoering and Quench and Tempering will influence Absorbe Energy levels. Was the material fully deoxidized? What is the Sulfur and Phosphorous contents. What is the Mn content. Don't expect muc help if the Mn < .70%, S > 0.15% and Si < .10% You main problem is selecting AISI/SAE 1026 rather than an ASTM Spec. with defined mechanical properties, greater defnition of chemistry and heat treatments.

 

[JPGraphX]

Just so you know, after a normalization, my charpy was way better!

FROM:
12 ft·lb/in longitudinal and 14 ft·lb/in transversal

TO:
60 ft·lb/in longitudinal and 23 ft·lb/in transversal

 

[EdStainless]

If you N&T, or Q&T you should even see slightly higher numbers.
But you are limited by the original chemistry.
I have seen this fight more than once.


= = = = = = = = = = = = = = = = = = = =
Plymouth Tube

 

[JPGraphX]

Oh yeah really? Higher number on charpy test with a Q&T ? that's weird!

 

[EdStainless]

It all hinges on grain refinement and test temperature.

= = = = = = = = = = = = = = = = = = = =
Plymouth Tube

 

[weldstan]

JPGraphX,
Thank you for the follow up info. What you have discovered is what you have been told; improvements can be achieved through normalizing.
I trust that the absorbed energy is now acceptable.

You can also specify toughness requirements in the P.O. to your materials supplier. Better to do that than hope that the material will meet as yet unspecified requirements.

 

[JPGraphX]

My requirement was 25 ft*lb/in. But 23 has been accepted!

Thanks,
JP

 

[OGMetEngr]

This same situation with a tube of slightly different chemical composition (e.g. - S, P, Mn), grain size, manufacturing method and variables, original heat treat condition, etc. could have had entirely unacceptable results. Even this same tube with another test or two could do the same. Best advice was already given, specify an ASTM and grade including charpy impact requirements and heat treatment if impact toughness is a requirement.

Also, this is a plain carbon steel tube in 2" wall thickness. You're not going to have equivalent properties through this thickness.