Profile: Onsite Stress Relieving specializes in custom engineering heat-treating system. We offer electrical and gas post-weld heat treating/stress relieving units. Our primary job function is stress relieving services. We offer weld preheating, post weld heat treating, refractory dry outs, process heat-ups, hydrogen bake-outs, piping and vessel stress relieving, coating cures, equipment rentals and calibration.