I need to weld a "Bell" and some support flanges to the bottom of a blunt point tool for a hydraulic breaker. I'm fabricating it to slam pipe in the ground.

The tool is hardened steel, and the pieces to make the Bell and supports are mild steel. I haven't ever needed to weld these 2 steels together. I want to make sure I'm welding it correctly, especially because the force of the hydraulic breaker. How do I weld these together? Thanks