The analysis presented in the article was concerned with cracks in MAG (135) robotic welded joints of pipes with eyes made of S890QL1 steel and constituting components of the latticework of self-propelled cranes. The text also presents results of tests concerning chemical composition as well as mechanical and metallographic properties of base materials and welded joints. The article contains an assessment of radial and longitudinal cracks of joints based on fractographic tests of cracks and impact-test specimens. The text also discusses the effect of welding process thermal conditions on joint properties. Test results were referred to the theory of hydrogen-induced cracking (mechanism) according to Professor E. Tasak.