Black pipe rusted again

oh forgot to add this:

my backup hand fed shop stove (warm morning) and my roomates ancient kenmore hand fed stove we burn wood in them in the fall and the spring, those chimneys last a long time and we never take those down (usually 2-3 seasons) something about coating the inside of the pipe with creosote first, it's gotta be that.......cannot burn wood in the efm or the alaska tho, and every yr replacing those chimneys lol

yes this is a 6,000 square foot chimney farm

Thanks for the ideas and suggestions guys. My stove is what used to be the garage now converted to family room. I took off the pipe in the spring and got the ash buildup off the inside, but didn't really scrub them clean. I then stuck them in my shed. Nothing rusts in there, tools, etc. I thought this would do the trick. It gets up to 110+ degrees in the summer in there. It was humid here though. My stove isn't showing any signs of rust though on the inside.