NEUTRON, X-RAY, AND FINITE-ELEMENT STRESS ANALYSIS ON BRAZED COMPONENTS OF STEEL AND CEMENTED CARBIDE

Abstract

Plates of cemented carbide were joined to steel by brazing. The structure was designed in imitation of a rock drill. Two types of steel were used which, after cooling from brazing temperature, showed a normalized ferritic–perlitic or a martensitic material state, respectively. Copper foil containing a nickel mesh was used as braze material. The residual stresses resulting from the different thermal shrinkage and elastic–plastic behavior of the materials as well as from the different phase transformation behavior of the steels during cooling of the samples from the brazing temperature (1100℃) to room temperature were investigated by neutron diffraction with special attention to the regions near the interface between steel and cemented carbide. Additional measurements were performed by X-ray diffraction on selected surface areas. Most of the experimental results could be satisfactorily modelled by three-dimensional finite-element calculations employing the temperature dependent elastic–plastic behavior of the materials. In particular, characteristic differences between the residual stress states of components with ferritic–perlitic or martensitic steel bodies were found experimentally as well as by the model calculations. Some points are discussed which require further investigations.