Investigation of Low-Carbon Pipeline Steel Weldability by Welding Thermal Cycle Simulation.

Results are presented for a study of the weldability of a wide range of pipeline steels by a method of simulating welding thermal cycles. It is shown that the method of simulating the microstructure by exposing base metal to a welding thermal cycle using a Gleeble test complex can be considered as a universal method for assessing steel weldability. The method makes it possible to evaluate steel reaction to thermal action for various welding methods and regimes, and in particular to establish the microstructure and mechanical properties (hardness, toughness, crack resistance). Alongside precise reproduction of the welding thermal cycle for a given range of pipes and welding modes, Gleeble makes it possible to separate the effect of individual thermal cycle parameters on the microstructure and to establish a number of important features. Microstructural mechanisms that determine formation of the heat-affected zone metal properties are discussed. It is shown that during simulation it is important to provide an austenite grain size corresponding to an actual welded joint and the type (section) of the impact specimen, which will allow comparison of material and welding technology. [ABSTRACT FROM AUTHOR]