Thank you all for your replies. I decided to go with 4130 steel but they are still a lot of questions:
The supplier is telling me that his products comply with ASTM A519 and I must decide if I want the tube normalized or stress relieved.
As far as I know, normalizing can soften/harden/stress...
I am very new in this domain. We are in the motorsport business and recently we started to design and produce rollcages. I have a few questions for the people who really know about steel properties.
We are working on a very light rollcage from 4340 alloy but I discovered that it has lower impact...