HIGH STRENGTH FERRITIC DEPOSITS WELDED BY SMAW, FCAW, MCAW, AND SAW: THE ISSUE IS TO OBTAIN TENSILE STRENGTH

ESTELA S. SURIAN (1) N. MABEL RAMINI DE RISSONE (2) HERNÁN G. SVOBODA (3) RODOLFO REP (4) LUIS A. DE VEDIA (5)

San Nicolás, Argentina

Conferencia; 2nd Conference on Uses of Steel; 2004

Instituto Argentino de Siderurgia

The understanding of the relationship between chemical composition, microstructure and mechanical properties of weld metal produced with a given welding consumable, allow a rational approach to the metallurgical design of the consumable, and the knowledge of the changes in mechanical properties induced by variations in the welding procedure parameters allow the optimization of the welding procedure for that consumable. When formulating manual covered electrodes, flux or metal cored tubular wires, and flux/electrode combination for submerged arc welding for depositing C-Mn-Ni-Mo or C-Mn-Ni-Mo-Cr low alloy ferritic steels, the first concern is generally related to factors that are deleterious to Charpy-V notch toughness, but this is not the only requirement of the AWS standard since it is also mandatory to satisfy tensile property requirements. In this work chemical composition of the deposit was varied and welding parameters were changed in the production of all weld metal samples according to the relevant AWS standards of the consumables employed. Tensile properties, hardness and Charpy-V impact toughness of the all weld metal specimens were assessed and metallographic studies were conducted with light microscopy in order to correlate mechanical properties with resulting microstructures. From the analysis of the results it was concluded that achieving the toughness required by the standards was not a problem. On the contrary, consistently satisfying the minimum requirements for tensile strength turned out to be a much more difficult problem demanding a rigorous approach to welding parameters selection in order to obtain repeatable results. On the other hand, for a given type of weld deposit, the requirements to be met differ according to the welding procedure employed thus adding another variable to the difficulties to satisfy the tensile requirements of the different standards.