Process and apparatus for welding workpiece have heat sensitive material are proposed. The heat sensitive material includes austenitic manganese steel, also referred to as Hadfield manganese steel. The process reciprocates filler metal in and out of weld pool. The motion of the filler metal may be synchronized with waveform of power source. Welding parameters are adjusted such that weld may be performed on the workpiece without cracking the heat sensitive material. The process allows Hadfield manganese steel to be welded to generator components in power generation applications. The process provides reliable and repeatable welding quality.