Hey folks, My team currently uses mild steel aisi 1018 for their car chassis. While it is OK, we are looking for lighter alternatives. Problem is that we have to use mild steel ONLY. So I was wondering if any of you could give me a good alternative for 1018 that is lighter, has greater torsional rigidity and is cheap and easily available. Please mention the grade, and any heat treatment processes followed. For information, we are based in India. South India basically. So anywhere near southern parts of India would be a great suggestion. Thanks in advance.