4340 crs vs hrs quench and temper 2

[Tmoose]

We are making some tension rods that require material with minimum yield strength of 860 N/mm² / 125 ksi. UTS 1000 - 1200 N/mm² / 145 ksi.
5.137" finish diameter, some nicely sculptured sections down to 3.543 " .

We called out 4340 CRS. The supplier is saying they are finding only HRS Q&T is available, and it will meet our yield and UTS specs.

Generically I believe Cold rolled steel has reduced grain size, which is in part responsible for higher yield and UTS, and fracture toughness.


My question - will Quenching and tempering HRS to some minimum yield and UTS values make it as "good" as CRS with similar yield and UTS ?

thanks,

Dan T

 

[metengr]

The cold rolled steel has greater dimensional control over hot rolled steel, and that is it about differences. Regarding mechanical properties, the Q&T will be more than acceptable for meeting your strength requirements.

 

[EdStainless]

TM, will these see a lot of cyclical loading?
If so then you might want to look at SBQ (special quality).
You will want better internal cleanliness.
The HR vs CR is not an issue in my mind.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, Plymouth Tube

 

[MagBen]

QT is the major means of developing mechanicals for this alloy. Cold work is often used to size a product form. It can be used to increase strengths, however, even 60% draft still significantly lower than those obtainable by QT.
BTW, it is unlikely to cold roll/draw 3.5-5.0'' bars.

 

[Tmoose]

thanks everyone.

Dan T

 

[TVP]

Just to add to what MagBen said, it is impossible to obtain round steel bars as Cold Rolled. Round steel bars can be Cold Drawn through a die, but not rolled. So specifying CRS will only lead to confusion. Cold drawing is very common in sizes below 2" in diameter. Very uncommon in sizes above this.

 

[Tmoose]

RE: Availability of cold drawn steel 4340 bars.

Maybe these folks are just funnin' with me, and an RFQ would get 48 month lead time response, but .............

https://www.onealsteel.com/alloy-steel-bar-cd-4340s.html

Diameter: 0.125" thru 12"
Stock Lengths: 10' thru 24'

http://www.eatonsteel.com/4340-cold-rolled-steel-bar.html

Eaton Steel Bar Company supplies 4340 cold drawn steel bar in a variety of sizes ranging from – 1 ½”-11”. The shapes available for this grade include:
Rounds

 

[Metaldoctor]

As was mentioned earlier, the main benefit of the cold drawn bar will be in dimensional control. The cold drawn grain size benefit will not transcend deep into the bar, as the drawing process will not elongate or refine the structure deep into the 5 inch diameter component. It will likely only give you grain refinement of the outer skin of the bar, depending upon how much reduction they see in the cold drawn process.
Using a hot rolled bar instead of the cold drawn bar in this case should be equivalent. if you were talking about a 1" diameter or .500" diameter bar the cold drawn grain structure would be more of a benefit.