Heat Treatment Vs Shot Peen 2

[Ach Arifudin H]

Hi all

Im Achmad Arifudin H, from indonesia, im new member in here, I am relatively new to shot peening, and have some questions regarding some parts I am currently may need shot peening.

for your information, i wanna shot peening root industrial gas turbine blade with udimet 520 material, but i have suggestions from other company that "if you do heat treatment (solution and aging for nickel based superalloy), you didnt need to shot peened the part, because the residual stress from operational have relief when heat treatment. but he didnt have reference, just his opinion".

do you have any information that heat treatment same treatment like shot peening in nickel based superalloy ??

Regards

Achmad Arifudin H

 

[EdStainless]

Controlled shot peen is used for a few reasons.
If you are trying to create some surface compression to counter other stresses in the part or as a general safeguard then a proper HT on these parts will take care of those.
However if the parts have a history of fatigue (and/or SCC attack) at a specific location the providing a controlled residual surface compression stress there should help offer some life extension.

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P.E. Metallurgy, Plymouth Tube

 

[Tmoose]

I did not look into your blade material to see if it had some unusual characteristics that would somehow limit the effectiveness of shot peening.

If the "other company"'s comment really was really as stated, my comment would be that shot peening goes FAR beyond (tensile) stress relief.

It induces a highly beneficial compressive residual stress in the surface.

A quick Google search will certainly result in explanations how properly done. shot peening improves fatigue strength, fretting fatigue resistance, and provides other important benefits as a result of the induced compressive stress.

 

[Ach Arifudin H]

@edstainless
"Controlled shot peen is used for a few reasons.
If you are trying to create some surface compression to counter other stresses in the part or as a general safeguard then a proper HT on these parts will take care of those.
However if the parts have a history of fatigue (and/or SCC attack) at a specific location the providing a controlled residual surface compression stress there should help offer some life extension. "
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Thanks for your information ed,

But how to know that the part have a fatigue material ??

Regards
Achmad Arifudin H

 

[EdStainless]

History.
It is common for turbine blades to be peened in the root and fir tree, these are the areas of highest stress in operation.
Many land based turbines are designed to be stronger (and heavier) than aero engines and a lot of this added material is specifically to fight fatigue.

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P.E. Metallurgy, Plymouth Tube

 

[weldstan]

There was a case where shot peening was done on the leading edge of turbine blades but subsequent machining removed the compressed area much to the chagrin of the turbine manufacturer and User. Very early turbine failures resulted. So be aware of design and manufacturing methods employed to meet the design.

 

[tbuelna]

One thing to consider when using mechanical surface enhancement processes (like shot peening) on components exposed to high temps (like turbine blades) is thermal relaxation of the residual surface compressive stresses. I believe surface enhancement processes that minimize cold working are less affected by thermal relaxation. So laser peening would be preferable to conventional shot peening if thermal relaxation is a concern.