Elva Sports Racer.
Your article on rebuilding an Elva sports racer is superb. I am using in comparison to my rebuild of an old Formula V racer, a Zink C4.
There is one error. Your suspension rebuilt uses 316 SS to replace AISI 1018 in a suspension link. 316SS is not a suitable structural material. It is too soft. It is primarily used in corrosive environments. If you need a stainless steel, 17-4 PH would be the choice, although it must be heat treated.
I checked with a materials expert with racing experience. 316 SS is not suitable suspension material but is excellent for race car exhaust systems.
My experience with316SS it is in industrial uses. Linkages made of it stretch and become useless under rather light loads.
Ralph Olmsted, PE
Material
Tensile Strength
Ultimate Strength
Elongation
Modulus of Elasticity
Carbon Steel, AISI Grade 1018
53,700 psi @ 2% elongation
63,800 psi
8%
29.0 x 106
Alloy 316 (S31600)
Min. 30,000 psi @ 2% elongation
75,000 psi
15.0 %
29.7 x 106 psi
17-4 PH steel (AMS 5604)
1100o F Heat Treat
Min. 155,000 PSI @ 2% elongation
Min. 170,000 PSI
10%
28.5 x 106 psi
17-4 PH steel (AMS 5604)
900o F Heat Treat
Min. 115,000 PSI @ 2% elongation
Min. 140,000 PSI
14%
Modulus of Elasticity 28.5 x 106 psi
Note:
AISI 1018 carbon is a good material for structural and machining applications. It is readily weldable without post-weld stress relief.
316SS is an austenitic chromium-nickel stainless steel with excellent corrosion resistance but not generally used for structural applications. Welding 316SS required special procedures to avoided weld contamination.
17-4PH is a grade of martensitic, precipitation-hardening stainless steel with the additions of chromium, nickel, and copper. 17-4 stainless steel has a valuable combination of high strength, good corrosion resistance, and toughness in both base metals and welds.
Stainless steels frequently have a thread galling problem. This is prevented by having a plating shop copper coat the threads.
Carbon steel properties courtesy of AISI (American Iron and Steel Institute). Stainless steel properties courtesy of Sandusky Steel Co.