Microstructural and Mechanical Characterization of Gas Metal Arc Welded AISI 430 Ferritic Stainless Steel Joints.

Ferritic stainless steels contain Cr as the main alloying element and display very good corrosion resistance even at high temperatures. These steels are widely used in manufacturing of products such as hot water storage units, car chassis components, exhaust systems and kitchenware. The most characteristic difficulty in fusion joining of this type of stainless steels is the grain growth in the HAZ. Furthermore, martensite formation or carbide precipitation along the grain boundaries in the HAZ may also be observed if the heat input used is extremely high or C content of the steel and/or filler wire high. Thus, it is required that the heat input should be kept low or filler wires with low C should be used to successfully join these steels by conventional fusion welding methods. The determination of the effect of heat input on microstructural evolution in the weld region and the mechanical properties of the joints in gas metal arc welding of AISI 430 ferritic steel plates is aimed in this study. To that end, AISI 430 ferritic steel plates with a thickness of 5 mm were joined using different heat input values. The microstructures in the weld region and mechanical properties of the welded joints were determined by extensive optical microscopy investigations, microhardness measurements, tensile and bending tests. Moreover, the heat input effect on the joint performance was also studied. [ABSTRACT FROM AUTHOR]