softening or annealing sae 9260

[pardal]

Hi all.

I have a few cold drawn sae 9260 round bar , size from 7/16" (11,11 mm) to 3/4" (19,05 mm) and I need to down its hardeness to less than 190 brinnel.
What could be the appropiate heat treatment .?
The pourpouse of this treatment is to allow a cold drawn reduction to get smaller diameter.
The material will be used to make car suspension springs, it will hardendened after coiling .


This the chemical composition
Component
Carbon, C 0.56 0.64

Iron, Fe 96
Manganese, Mn 0.88
Phosphorous, P 0.035
Sulfur, S 0.04
Silicon, Si 2
Thanks in advance Pardal

 

[Metalguy]

You can anneal it down to around 260 BHN-use around 1575 deg F. I don't think you'll get the hardness below that.

 

[CoryPad]

9260 that has been speroidized annealed can have hardness as low as ~ 184 HB. To spheroidize anneal, you can do two things:

1) heat to 760 &[ignore]deg[/ignore];C (1400 &[ignore]deg[/ignore];F) then cool to 705 &[ignore]deg[/ignore];C (1300 &[ignore]deg[/ignore];F) at a rate not to exceed 6 &[ignore]deg[/ignore];C (10 &[ignore]deg[/ignore];F) per hour.

or

2) heat to 760 &[ignore]deg[/ignore];C then cool rapidly to 665 &[ignore]deg[/ignore];C (1230 &[ignore]deg[/ignore];F) and hold for 10 hours.

Since you are looking for the low end of possible hardness, you may need to use slightly longer times at temperature.

 

[pardal]

thanks for it boys.

have a happy week end
Pardal Pardal

 

[TVP]

pardal,

I'm not sure if you already know this, but using SAE 9260 with 0.04% Sulfur for an automotive suspension spring is not a good idea. This level of Sulfur will result in many sulfide inclusions which greatly reduce the fatigue strength. Typical Sulfur levels from true spring steels are more like 0.008%.

 

[pardal]

Hi tpv .

This composition was token from a data sheet, not from a chemical analysis.
I will check it .

Thanks for the tip. Pardal