1144 CD Steel vs. 1144 Stressproof

[Casey96SS]

It appears the mechanical properties are similar between 1144 CD and 1144 Stressproof. Any reason not to use 1144 CD if mechanical properties are acceptable? Basically wondering if the are any hidden disadvantages to 1144 CD. This material will be used for motor shafts. Considering listing either material as an option since mechanical properties are acceptable for either one.

Thanks for any input.

 

[MikeHalloran]

My limited experience with Stressproof says only this:

If you don't buy Stressproof >G-P<, you'll have to machine off 1/8" of 'bark' on either side, so you'll need to start with bigger stock.



Mike Halloran
NOT speaking for
DeAngelo Marine Exhaust Inc.
Ft. Lauderdale, FL, USA

 

[swall]

1144 CD is cold drawn. The cold drawing will tend to offset the deleterious effects of any decarb that might have been present in the original hot rolled bar.So, you can buy the bar size you need.Big difference I see is that StressProof comes with guarranteed min properties, whereas 1144 CD doesn't.

 

[metengr]

I would stick with purchasing 1144 bar that has guaranteed minimum mechanical properties for shaft applications. Fatigue strength is critical in shaft design, and any variation in mechanical properties and surface decarburization will have adverse effects on fatigue strength.

 

[BigMet]

Stressproof is heavy drawn and stress releived bar to minimum properties. If you can live with 1144 cold drawn regular do so.

 

[lgearhart]

Why not buy your 1144 per ASTM A311, Class B? That way you have your mechanical properties spelled out. Should your suplier want to give you Stressproof from Niagara, they can, or they can send you something else that meets the spec.

I ALWAYS prefer buying something to a specification, and I can't believe you'll have trouble finding material per ASTM A311 Class B.

Good luck!

 

[TVP]

I completely agree with Mr. Gearhart's suggestion. This always minimizes any confusion on required properties, testing, etc.

 

[Casey96SS]

Thanks for all of the replies and input.

We ended up specifying "ASTM A108 1144 COLD DRAWN STEEL -OR-
STESSPROOF ASTM A311 CLASS B 1144 CD STEEL"

Mechanical properties work for either material and it solved a purchasing/vendor problem. I am sure they will be asking to use a different material next week.

 

[BobM2]

Another question on Stressproof: Doesn't the cold working leave a residual compressive stress only near the surface? So if the surface was machined down, wouldn't you lose that advantage?

 

[BillPSU]

Its been a while since I reviewed the specs on cold drawn but I believe the specifications gives only typical properties of a cold drawn shaft and as the size increases the strength decreases. Stressproof on the other hand gives minimum strength values for whatever diameter is used.

 

[Casey96SS]

Could someone tell me if the mechanical properties for 1144 CD are the same at the core of the material as they are at the surface. I would think they would be the same since the entire cross section of material is being compressed as it is being cold drawn. This is not considering any heat treating or stress relieving, just cold drawing.

 

[metengr]

FYI;
Very interesting thread below on this entire subject regarding Stressproof 1144 steel;

thread330-21337

 

[gearman1234]

We used to use 1144 CF (1.25 dia) and stress relief annealed and 1144 STresproof (1.5 dia) for different applications. The mechanical properties are as follows.

Stress proof-- YTS- 115.66 ksi, UTS- 138.21 ksi, Hardness- 29 HRc. from Niagara

1144 CF (from a different mill)-- YTS-- 106.1 ksi , UTS -- 129.6 Ksi, Hardness- 21 HRc
The chemistry matches for both. They both are equivalent to A311 CL B

But I believe that essentially both are same except the hardness and a little lower YTS/UTS.

Hope this helps.

BTW what is the dia/torue/rpm , what is the rating factor? All these things need to be considered while choosing the material.

 

[mewhg]

FYI - We use some precision machined bushings made from Stressproof. Our screw machine shop is able to hole 0.0005" tolerances on the bore ~.145" dia and OD ~.250" dia.