The objective of the paper is to present the newest results of our complex research work. In order to determination and comparison of the fatigue resistance, fatigue crack growth tests were performed on different grades of S690QL quenched and tempered, and S960TM thermomechanically rolled high strength steels.15 mmand30 mmthick base materials were used for our investigations. Welded joints were made from these base materials, using gas metal arc welding with matching, overmatching, and undermatching filler metals. In the paper, the performance of the welding experiments will be presented, especially with the difficulties of the filler material selection; along with the results of the fatigue crack growth examinations executed on the base materials and its welded joints. Statistical aspects were applied both for the presenting of the possible locations of the cracks in the base materials and the welded joints and for the processing of the measured data. Furthermore, the results will be compared with each other, and the possibility of derivation of fatigue crack propagation limit curves will be referred.

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The objective of this article is to present the first results of our research work. In order to determination and comparison of the fatigue resistance, high cycle fatigue tests (HCF) were performed on RUUKKI OPTIM S690QL quenched and tempered high strength steel. In parallel these; welded joints were made on the same steel using gas metal arc welding (GMAW, MIG/MAG) to preparation of the cyclic investigations of the welded joints. In the article, the performance of the welding experiments will be presented; along with the results of the HCF tests executed on the base material and its welded joints. Furthermore, our results will be compared with different literary data.

Jelen kutatómunka célja S690QL és S960M alapanyagok és védőgázos fogyóelektródás ívhegesztett kötéseik fáradásos repedésterjedéssel szembeni ellenállásainak meghatározása. A hegesztési kísérletek 15 mm vastag alapanyagokon lettek végrehajtva, szimmetrikus X kötéskialakítást alkalmazva. A paraméterek állandósága érdekében hegesztő szekátort alkalmaztunk, illetve WeldQAS folyamatfelügyelő rendszer segítségével ellenőriztük a hegesztési paramétereket. A repedésterjedési próbatestek a jellemző irányokra merőlegesen illetve azokkal párhuzamosan lettek kimunkálva, mind az alapanyag, mind a hegesztett kötések esetében, illetve ez utóbbi próbatestek során a bemetszések helyzetét is változtattuk. Ennek megfelelően a vizsgálataink során terjedő repedések a valós szerkezetekben előforduló és megjelenő, különböző repedés megjelenési helyeknek felelnek meg. A vizsgálati eredmények megfelelő módon kiválasztott értékinek felhasználásával egy statisztikai módszer javasolható a fáradásos repedésterjedéssel szembeni ellenállás meghatározására.

The objective of this article is to present the newest results of our research work. In order to determination and comparison of the fatigue resistance, high cycle fatigue tests (HCF) were performed both on SSAB WELDOX 700E (S690QL) quenched and tempered and VOESTALPINE ALFORM 960M (S960TM) thermomechanical high strength steels. Welded joints were made from these base materials, using gas metal arc welding (GMAW, MIG/MAG) with matching filler material. In the article, the performance of the welding experiments will be presented, especially with the difficulties of the filler material selection; along with the results of the HCF tests executed on the base material and its welded joints. Furthermore, our results will be compared with different literary data.