Friction Welding Technology for Boring Rod

Abstract

Friction welding method was applied for connecting a steel tube(STM-R80) for drilling and tool joints(SCM-3). At the first stage of the experiment, owing to the fast cooling velocity in and around the welded part, the hardness came up to Hv500 maximum, hence, annealing treatment was required. To improve it, the friction time was prolonged to give a wide heat effect range on thewelded part, which was then cooled down, slowly.As a result, the hardness ofthe welded part was reduced to a maximum of Hv350, and a narrow rang of hardness distribution was obtained around them. In this case, annealing treatment could be omitted. Test pieces welded under the latter condition were used for tention, bending and torsion tests. From these three tests, we could get satisfactory results for practical use.