The final paper analyzes the occurrence of cold cracks with respect to influencing factors. In practice, detailed experiments, studies, analyzes of the chemical composition of the material and the temperature parameters that cause it are performed. Some of the methods that are mechanically applied to test specimens are explained in detail in the chapter on methods for testing the susceptibilty to cold cracks. Here are mentioned the three most common methods that are from a financial point of view satisfying the required information of weld grain behavior on tensile strength, toughness and other mechanical characteristics. Cold cracks are also called hydrogen cracks or delayed cracks. They are called like that because of the presence of hydrogen, but the influence of microstructure and residual stresses, the main culprit for their appearance, base material is absorbing hydrogen into the metal, and further cooling of the metal, hydrogen remains trapped between grain boundaries. This further shrinkage has a very negative effect. on the structure and properties of load-bearing parts of structures. Several types of steels are described that are very resistant to welding by their content using the Gravielle weldability diagram, here there are 3 zones in which there are different types of steels, from carbon to high-alloy. At the end of the thesis are influential factors that can be calculated by standard numerical modes in terms of achieving the best possible connection between the metals which had to be welded. The preheating parameters, material thickness limits, cooling duration from 800 ℃ to 500 ℃, Schaeffler diagram with areas of different structures expressed in terms of chromium and nickel equivalent and the area of optimal welding.