I want to add a couple of bars to my basic 6-point cage. It's 1.5 inch chromoly. Must I use chromoly for the new bars? one end of each bar will be welded to the main hoop, the other end to the chassis. Thanks.

 

Basically-yes. Chromoly is not the same as mild steel. Keep in mind that it also is prone to cracking in high stress areas. You should do an annual inspection of the cage using proper techniques to insure weld integrity. This happens to be the downside of the material versus mild steel. Unless you can insure the quality of the welds and their structural integrity-stick with the same material thruout the cage.

 

I believe Chrome-moly matieral needs to be normalized after welding or special proceedures need to be followed or the tubing will not be as strong as referred to above.