Evaluating the Crack Resistance of Carbon Anodes: Implementation of a Measurement System for Tensile Strength and Fracture Toughness

Monitoring anode mechanical strength is increasingly important in production and operation of carbon anodes in high amperage cells due to higher crack driving forces. To achieve a better understanding of the directional crack resistance of the anode, a laboratory testing rig has been developed and installed at Hydro Aluminium Primary Metal Technology. The rig consists of a high-precision testing machine and a Hydro-developed measurement system which calculates the Young’s modulus of elasticity, the tensile strength, the fracture strain and the fracture toughness. The equations of the physical parameters are derived from a finite element modelling of the specimen loadings, and are implemented in a Hydro developed laboratory software which computes the values from load-deflection data and transfers the parameters to a database. The paper outlines this method including the sample preparation machine.