Research on the mechanical properties of the weld seams of constructional steel using vibration energy method during welding

The paper analyzes changes in the mechanical properties of the welded joints of steel S355J2 (LST EN 10025) using vibration energy method during welding done by applying semi automatic equipment under CO2 environment using supplementary wire ESAB OK 12.51. When welding, several levels of vibration energy are applied. For vibration treatment, proprietary equipment “MetaLax 2725” produced by the U.S. Company “Bonal” was employed. To investigate the effects of vibration energy on the weld seam, radiographic control and mechanical experiments on tensile, hardness distribution and impact resistance were performed. Article in Lithuanian. Konstrukcinio plieno suvirinimo siūlių mechaninių savybių tyrimas suvirinimo metu naudojant vibracijos energiją Santrauka. Darbe nagrinėjamos statybinio konstrukcinio plieno S355J2 (LST EN 10025) suvirintųjų jungčių mechaninės savybės, suvirinant vibracijos energija. Bandiniai buvo suvirinami pusautomačiu apsauginių dujų aplinkoje CO2, naudojant pridėtinę vielą ESAB OK 12.51. Suvirinant taikomi keli vibracijos energijos intensyvumo lygiai. Vibraciniam apdirbimui naudota JAV kompanijos „Bonal“ patentuota įranga „MetaLax 2725“. Siekiant ištirti vibracijos energijos poveikį suvirinimo siūlei buvo atlikta radiografinė kontrolė, tempimo, smūginio tąsumo ir kietumo mechaniniai bandymai. Reikšminiai žodžiai: vibracijos energija, suvirinimas, konstrukcinis plienas

Influence of Vibratory Stress Relief on Residual Stresses in Bridge Structural Members Weldments

The welding process can join two similar materials with a bond that has mechanical properties comparable to the original material. Unfortunately, this process induces residual stresses in the weldment, which, if left untreated, can cause distortion of the part, premature fatigue failure or cracking along the weld. In a cases of cracking in steel bridge structural members were attributed to metal fatigue. The majority of these fatigue cracks are initiated adjacent to a weld. A post-weld heat treatment is the traditional method of relieving these stresses, but is costly and a time consuming process. Heat treatment is required for weldments, which have heavy fatigue loading since the post-weld heat treatment reduces the residual stresses in the weldment and generates more uniform mechanical properties. Vibratory stress relief techniques could be used to substitute the heat treatment for these types of weldments and save time and money. The purpose of this paper is to provide a brief overview of the generation, measurement, and reduction of residual stresses. Residual stresses in the weld bead were measured by means of X-ray diffraction, neutron diffraction, ultrasonic technique, hole drilling and numerical methods. In addition, welded specimens were subjected to mechanical testing with purpose of determination of VSR effect on weld and heat-affected zone metal