Rotary Friction Welded C45 to 16NiCr6 Steel Rods: Statistical Optimization Coupled to Mechanical and Microstructure Approaches

Abstract

This work represents the production of dissimilar friction welded joints between C45 carbon steel and nickel-chromium alloy steel 16NiCr6. Central Composite Response Surface (RSM) methodology, optical microscopy, scanning electron microscopy (SEM), backscattered electron diffraction (EBSD) and bending test were performed for this study. Physicochemical characterization was used to reveal the welded joint microstructures. The bending test was done in order to measure the ultimate bending strength (UBS). As a conclusion, regarding the optimization of the parameters, friction time and the rotation speed were the most effective parameters on the joint strength. These parameters revealed that the maximum bending strength of 1406.892 MPa can be obtained at a rotational speed of 2000 rpm, a friction pressure of 24.77 MPa and a friction time of 13 seconds. On the weld samples it was also noted that the particle size decreases significantly as the units of the parameters increase, which led to note that the optimization of these parameters converges towards an average particle size, where were found a good accommodation between hardness and young’s modulus.