Large Electrodes: Strength and Elasticity Requirements Analyzed

Handan Qifeng Carbon Co., Ltd., a manufacturer of carbon products, has analyzed the required tensile strength and elastic modulus characteristics for large electrodes, with diameters of 700mm or more, under extreme working conditions.

The company states that flexural strength and elastic modulus need to be differentiated based on electrode grade (regular, high, or ultra-high power) and the specific application scenario, such as large electric arc furnaces or submerged arc furnaces. For ultra-high power electrodes operating in harsh conditions, flexural strength typically needs to exceed 10.0 MPa, while the elastic modulus should be controlled below 14.0 GPa to enhance thermal shock stability while maintaining mechanical load-bearing capacity.

The analysis highlights that flexural strength and elastic modulus are key parameters requiring balance. Flexural strength determines the electrode's resistance to fracture, whereas the elastic modulus reflects material rigidity. An excessively high elastic modulus can render the material brittle and prone to cracking during severe temperature fluctuations.

Industry standards, such as YB/T 4090, generally require ultra-high power electrodes of Φ550–700 mm to have a flexural strength of at least 10.0–12.0 MPa and an elastic modulus not exceeding 14.0 GPa. Some enterprise standards tighten the elastic modulus requirement to 7.0–10.0 GPa to achieve superior thermal shock resistance.

For regular power electrodes used in submerged arc furnaces, which have lower current density requirements, flexural strength needs are lower (≥6.0 MPa) and the elastic modulus is controlled at ≤10.0 GPa. High power and ultra-high power applications, facing greater current and vibration, typically require flexural strengths of 8–15 MPa and elastic moduli between 8–14 GPa. Optimization of aggregate composition and baking/impregnation processes can yield elastic moduli as low as 7–9 GPa.