4140 vs 4130 2

[MP25PK]

Hey Guys:

I am looking for some more detailed information about the difference between 4130 and 4140 alloy. What if a tube size is
4130 .750 OD X .156 W (.438 ID)

vs

4140 7/16" outside diamter x 14 gauge (.083")

Now i know that 4140 has a higher carbon content than 4130 but if you have a larger diameter 4130 over the 4140 where does that 4130 become equally strong if not stronger than the 4140. 4140 is harder yes and can be hardened to a high Rockwell but doesn't that also make the material more brittle?

I am open to all information on this topic.

 

[metengr]

If you are looking for chemical composition and mechanical properties data this is readily available for 4130 and 4140 alloys by searching on the internet. Beyond this, you appear to be comparing thin wall and thicker wall tubing between 4130 and 4140. Think about what information you really need other than an alloy comparison, which I addressed.

 

[mrfailure]

Think about the pressure and design stress of your application requirements. Use an appropriate tubing material specification (e.g. ASME) that your material is certified to, then you can determine if both tubes will meet strength requirements. (ASME B&PV Code Material volume will give you specified and design material requirements for the selected specification you use for your material). Note that your application very well may not need higher/hardness strength properties you could achieve with 4140 in which case it makes no sense to to that direction.

 

[weldstan]

Through thickness hardening will occur with either material. Ductility will be a function of tempering temperature. What properties do you really need?

 

[Guest102023]

Those are two wildly different tube gauges. It seems to me you have put the cart before the horse by making design a choice between two products that happen to be available. I repeat the suggestion already made, that you start by defining your requirements. Either alloy is capable of producing impressive strength/hardness at these gauges.

If this is for a heat exchanger, you probably want to bias toward thinner gauge for efficiency. If this is a structural application, remember that strength is a function of geometry as well as material properties.

"If you don't have time to do the job right the first time, when are you going to find time to repair it?"