International Scientific Journals
of Scientific Technical Union of Mechanical Engineering "Industry 4.0"

The work is performed by analysing spiral welded joints Helical Submerged Arc Welding and their most common errors, which they occur during the submerged arc welding process and can be detected by non-destructive tests. Pipelines were made of structural alloy steel, hot-rolled. Welded defects were detected by X-ray method. A microstructural test was carried out to detect internal errors of the weld joint. Mechanical tests were used to determine the effect on change of properties. After detecting errors on the end X-ray, they were welds subsequently corrected. Destructive or non-destructive testing of gas pipeline welds has its justification, mainly for safety reason.

The paper presents the results of quality evaluation of weldments produced by a mutual combination of different steel grades. Weld joints were made using GMAW technology (method -135 ISO 4063). The type of welding parameters used for the quality of welded joints was monitored. The quality of welded joints was assessed using non-destructive tests. In non-destructive tests, the Visual test according to EN ISO 17637, the Penetration test with colour indication according to EN ISO 22476-12 was used to identify surface defects. The presence of internal errors was assessed by a radiation test according to EN ISO 17636-1. Within the destructive tests, the quality of the welds was assessed by a tensile test according to EN ISO 6892-1, by the test of brittleness of welds according to EN ISO 5173, the course of hardness according to EN ISO 6507-1 was determined on transverse cuts. The bending impact test according to EN ISO 9016 will determine the toughness of the weld metal and heat-affected areas. Metallographic analysis of welds according to EN ISO 17639 was performed on transverse metallographic sections using light microscopy. Based on the performed experiments, recommendations were set, or proposed changes in the welding procedures of the given steel grades.

Because of the combination of high specific strength and excellent corrosion resistance in many media, titanium and titanium alloys are used in aerospace engineering, chemical industry, mechanical engineering etc.
The present work introduces results that demonstrate the effect of the thermal cycle on mechanical properties of Grade 1 Titanium welds, produced by hollow cathode arc discharge in vacuum. Dimensions of the welds were established. The mechanical properties of the welds – hardness and tensile strength – were determined. The influence of the thermal cycle on welds structure was investigated.