Experimental Comparison Study on Stress Relief for Welded Low Carbon Steel (St 37) Bar by Vibration Mechanism and Heat Treatment Process

In this paper An Experimental process of vibration stress relief (VSR) and post-weld heat treatment (PWHT) after welding the resonant vibration is implemented. Depending on the vibration frequency as the indications for stress relief for a Welded Low Carbon Steel (St. 37) Bar. The vibration frequency should be applied to the structure and the structure natural frequency should be close each other in vibration mode, and with small vibration amplitude which will be amplified during vibration under a 7 N force of frequency which it close to the natural frequency of the welded bar (at resonance) for 20 mints. When the amplitude of vibration in the stress relief became large, then the treatment will be more effective. The (PWHT) is employed for comparison, and indication that the stress been relief are take place by mean of metallurgical and mechanical properties development and change in the natural frequency before and after treatment lead to change the amplitude for small to larger also indicate that the stress been relived.