F53 Duplex SS forgings crack during heat treatment

[metmike]

Hi everyone,
I have a problem regarding F53 duplex SS. We were annealing 2-1/2" OD forgings in-house at the recommended ~2000 deg F. The forgings were taken out even before any quenching with long cracks along the surface or even split in half. I know that the intermetallic sigma phase can cause a severe reduction in ductility.

This may not be much information to give a good analysis, but any ideas as to how this may have happened would be greatly appreciated. I will try to provide any further info that is requested.

Pictures of the cracked forgings are attached

 

[metengr]

Do you have any specifics on the forging process and thermal history before your solution treatment? It may well be these forgings contained cracks from the forging process due to lack of temperature control, and upon a subsequent solution treatment resulted in the observed failures. The fracture surfaces appear to exhibit a multi-faceted brittle fracture appearance.

 

[WSALDUA]

Seems kind of odd that one might recieve product without some sort of bill of materials that would garauntee sound forging material (crack free and correct chemistry). From the .jpg pitures, looks like there are river lines that initiated internally. I wonder if the chemistry is out from the get go, or your heat treat furnace is somehow contaminating the forging during annealing ?

 

[Maui]

As mentioned by metengr, some grades of duplex stainless steel are very temperature sensitive and require careful monitoring during forging, especially if they possess relatively thin corners that cool much more quickly than the core. For example, see

http://www.imoa.info/_files/stainless_steel/IMOA_Shop_Sheet_101.pdf

Maui

http://www.EngineeringMetallurgy.com

 

[stanislasdz]

Do you provide Ultrasonic testing according to EN 10228-4 before Annealing?

Can you provide us chemical composition with all residual elements?

What is the hot working Ratio?

What is the ramp up velocity of the furnace?

What is the temperature of the forgings when it was introduced in heat Treatment Furnace?