Chromoly Vs Mild Steel K Member

Use er70s wire and you won t need to passivate the welds since the wire is ductile.

Chromoly vs mild steel k member.

A sfi 25 5 cage can be either mild steel or chromoly however a 25 2 cage must be chromoly only. Ths tress relieving part is bogus. But the fact is someone has had a problem with all brands steel or chromoly. Some are stronger then others but some you are going to pay out the ass for.

When racecars were just beginning to be made from chrome moly there were brittle failures caused by the lack of heat treating and stress relieving. Upr s all new chrome moly k member will save more weight and exceed any strength limitations of mild steel while allowing maximum header and oil pan clearance. A 25 2 cage will cert a car to run 6 0 and slower at 3200 pounds max. I am cheap so upr was the one for me they have had their problems in the past but the k members have been redesigned and are much better.

In nasa we have to use the same gauge whether it is mild or chromoly so the benefit of light weight is not as great. 4130 alloy steel carbon steel vs. Drag racers benefit more from using chromoly because they can use a thinner wall steel over mild. Chromoloy tubing is made from a family of low alloy steels that contain chromium and molybdenum sae 4130 or 4140 along with the iron carbon and other elements.

Crome molly chromemoly has a higher ultimate strength so it is much harder and a mild steel cage will fail before it does. Also keep in mind that it is harder to weld the 4130 than the mild steel. There are going to be people saying chromoly will crack or i have this friend that blah blah blah. This kit was designed for the abuse of hardcore drag race road race and street enthusiasts.

I did not understand either as i came from drag racing but that is what the ot sanctioning bodies require. The chromium adds strength hardenability and a level of corrosion resistance to mild carbon steel though chromoly is not as corrosion resistant as stainless steel.