BODY PANEL CONSTRUCTION CN-3 HIGH–STRENGTH STEEL (HSS) PARTS Generally, High–Strength Steel (HSS) is that which has an intensity value of at 35 kgf/mm2 (343 MPa), and distinguished from mild steel. The handling of HSS is the same as for mild steel, but the following should be observed. 1. Panel Hammering: Because HSS is thinner than mild steel, care should be taken to avoid warping during hammering operations. 2. Removing Spot Welds: Because HSS is tougher than mild steel, damage will occur more easily to a regular drill. Therefore, an HSS Spot Cutter is recommended. Also, use a high–torque drill at low speed, and supply grinding oil to the drill during use. 3. Panel Welding: Panel welding procedures for HSS are exactly the same as for mild steel. Plug welding should be done with MIG (Metal Inert Gas) welder. Do not gas weld or braze panels at areas other than specified. : High–Strength Steel