I have a primary pulley for my bike that I need to weld a spacer on. The two parts were advertised as steel. I took a cut on both and they seem to cut like cast steel. I don't think they are cast iron, but I'm not 100% sure. I tack welded them with my tig and the tacks cracked right away. I'm thinking it's because I didn't preheat. I used regular steel rod. I have stainless rod. Would this be a better choice. Or should I use something else? The part shouldn't see alot of stress, but I would like it to be strong if I can. Any suggestions would be great. Thanks