Failure of Riveted and Forge-Welded Penstock

This paper describes the failure and repair of a 1920's vintage 78-in. (198-cm) diam, 1-1/4-in. (3.18-cm) thick riveted and forge-welded penstock. The failure occurred at a metallurgical discontinuity located in a forge-welded joint when the turbine shut-off valve swung closed in less than 3 sec.