About 1026|The tubing steel. Most hot-formed mechanical tubing is 1026. Slightly more carbon than
1018/
1020 (0.22-0.28%) which gives it a bump in strength without making it significantly harder to machine. In practice, machinists describe it as almost indistinguishable from 1018 or 1020 at the lathe. Chips slightly cleaner than 1018 due to the higher carbon, but the difference is marginal. Welds fine. The main reason you'll encounter 1026 is because the tubing you bought happens to be made from it. If you're buying bar stock for machining, you'll almost never spec 1026 over 1018 since 1018 is more available and cheaper in bar form. Compare to 1020 (slightly weaker, common substitute) and 1018 (the go-to for bar stock).
