Welding conditions are a set of technological and design factors affecting the welded joint during its execution. They depend on the method used (especially on the type of filler metal used) and welding parameters. Heat treatment after welding has a decisive influence on the state of stresses in the joint and on the mechanical and functional properties of the joint. Welding conditions are determined by the welding technology used and construction solutions imposed by the designer.

The usefulness of a welded joint is the possibility of its use in given operating conditions, which are the criteria for assessing weldability. If for a given steel it is possible to obtain joints with the desired utility by many different methods in a wide range of parameter changes, without the need for special technological procedures, then such steel can be considered as easily weldable. The usefulness of welded joints is determined by various strength tests, fatigue tests, corrosion tests, operational tests, etc.