Impact Strength (mild steel tubing)

[Restomod]

I need to calculate what percentage increase in impact strength I will get by inserting a 1" OD round tube with .083 wall inside a square 1 3/4" width tube with a .059 wall. Both are mild steel, ERW tubing. Check attached file for diagram.

I can find out the tensile strength, if that is needed in the calculations. Can anyone help in how to go about this ?

Thx.

 

[Astronuc]

What equations is one using? What type of mild steel - and it annealed or cold-worked? What is between the pipes?

Here is an example of a 1020 steel (as rolled) - http://www.matweb.com/search/SpecificMaterial.asp?bassnum=M1020D

Here is an example of an ASTM A53 Grade A/B
http://www.macsfs.com/pdf/astma53grabp1718.pdf [Broken]

In addition to tensile strength, one would need to know fracture toughness.