TWI Industrial Member Report Summary 230/1984
By S B Dunkerton
The effect of welding parameters and component geometry on mechanical and metallurgical properties has been investigated for conventional friction welds in a carbon manganese steel to BS 2712 150M19. The steel was purchased in 51mm diameter bar form, from which both bar and tubular (12.7mm wall) welds were produced. The particular cast of steel used contained a very low sulphur content of less than 0.005%. Over the range of welding conditions examined, the bend properties were good while the as-welded impact properties generally exhibited poor lower shelf energies, but increased energies above -40°C dependent on the welding conditions. The use of high burnoff rates and long deceleration times led to improved impact properties, particularly for tubular welds. With respect to the latter, one welding condition resulted in weld impact properties which were greater than the as-received parent metal at the lower testing temperatures. The impact properties of tubular welds were similar or better than the corresponding solid bar welds. Postweld heat treatment (PWHT), in the form of a normalise or a quench and temper, substantially improved the weld impact properties such that the heat treated parent metal energies were reached for certain welding conditions.