On the basis of national standards, each enterprise has its own enterprise standards, and customers will also propose their own quality standards when ordering.

The indicators reflecting the quality and performance of graphite electrodes are: bulk density db, resistivity ρ, flexural strength σ, elastic modulus E, thermal expansion coefficient α and ash A%. According to the differences in these indicators and the differences in raw materials and manufacturing processes, graphite electrodes are divided into regular power graphite electrodes (RP) , high power graphite electrodes (HP) and ultra high power graphite electrode (UHP). After that, the graphite electrode production plant increased two types of high-density graphite electrodes (HD) and quasi-ultra-high graphite electrodes (SHP) according to user needs.
 
 
 Bulk density is the ratio of the mass of graphite electrode sample to its volume. The unit is g / cm3. The larger the bulk density, the denser the electrode. It is positively related to the strength and oxidation resistance. Generally speaking, the larger the bulk density of the same type of electrode, the The lower the resistivity.
 

  The way to increase the bulk density is to adjust the formula, increase the use of small-grain grades and powders, use high-density coke, use bitumen with high coking value, and increase the number of impregnations.
 

  Resistivity is a parameter to measure the conductivity of an electrode. It refers to a property of the resistance of the conductor to the current when the current passes through the conductor. It is numerically equal to the resistance value of a conductor with a length of 1m and a cross-sectional area of ​​1m² at a certain temperature. Unit: μΩ · m. The lower the resistivity, the better the conductivity of the electrode in use and the lower the consumption.

 
  The ways to reduce the resistivity are: using high-quality raw materials, increasing the bulk density of the product, and increasing the graphitization temperature.
 
 
  Flexural strength is a parameter that characterizes the mechanical properties of graphite materials. It is also called flexural strength. It refers to the ultimate resistance of the object to the moment of bending when the external force is perpendicular to the axis of the object. The unit is MPa. The strength of graphite materials is significantly different from other metals and non-metals. Its strength increases with increasing temperature, reaching a maximum at 2000-2500 ℃, which is 1.8-2 times the normal temperature, and then decreases. High-strength electrodes and connectors are difficult to break in use.
 

  The way to improve the flexural strength is to reduce the particle size of coke in the formula, increase the strength of the carbonaceous raw materials, increase the bulk density of the product, and reduce internal defects of the product.
 

  Modulus of elasticity is an important aspect of mechanical properties. It is an index to measure the elastic deformation ability of a material. It refers to the ratio of stress and strain in the elastic deformation range of a material, the unit is GPa. The larger the elastic modulus, the greater the stress required to produce a certain elastic deformation. In simple terms, the larger the elastic modulus, the more brittle the material, and the smaller the elastic modulus, the softer the material.
 

  The level of the elastic modulus plays a comprehensive role in the use of the electrode. The higher the bulk density of the product, the denser the product, and the larger the elastic modulus, but the worse the thermal shock resistance of the product, the more likely it is to crack. In production, often through the adjustment of the formula grain level, the volume density of the product to master a more suitable elastic modulus value to meet the requirements of use.
 
 
  Thermal expansion coefficient is a measure of the degree of expansion of a material after it is heated, that is, when the temperature increases by 1 ° C, the expansion constant of the solid material sample in a specific direction caused by the unit is called the linear expansion coefficient in that direction, the unit 1 × 10-6 / ° C. Unless otherwise specified, the thermal expansion coefficients refer to the linear expansion coefficients. The axial and radial linear expansion coefficients of graphite electrodes are very different. The radial expansion is 0.8-1 times larger than the axial direction. The thermal expansion coefficient in the quality index of graphite electrodes Refers to the axial thermal expansion coefficient.
 

  The thermal expansion coefficient of graphite electrodes is a very important thermal parameter. The lower the value, the stronger the thermal stability of the product and the higher the oxidation resistance. The less the breakage is reflected in the use, the lower the consumption.
 

  The way to reduce the coefficient of thermal expansion: The quality of the raw materials is mainly determined by the inherent properties of the raw materials. The formula uses a larger particle size or increases the amount of large particles (but it will reduce the density and strength of the product).
 

  Ash refers to the content of other solid elements in the product besides carbon graphite. The ash content in graphite electrodes is mainly affected by the ash size of the raw materials used. The ash content of petroleum coke needles is relatively low, so the ash content of graphite electrodes generally does not exceed 0.5%, and the ash content within 1% has no obvious effect on steelmaking. Impurity elements reduce the oxidation resistance of the electrode.

 
  The thermal shock resistance factor is a parameter characterizing the thermal shock resistance. The thermal shock resistance is a characteristic of the material itself. It expresses the performance of withstanding the rapid cooling and heating. In other words, it is the temperature of the material at a certain temperature gradient. A performance of anti-cracking is a very important comprehensive factor affecting the use of the electrode.

 
K——thermal shock factor, w / m; σ—tensile strength, MPa; E—elastic modulus, MPa; λ—thermal conductivity, w / m · k; α—thermal expansion coefficient, 1 / KK is a relative value. The larger the value, the stronger the thermal shock resistance. The K value of a graphite electrode has a high correlation with its performance in an electric arc furnace, that is, a higher K value corresponds to a lower fracture and fracture of the electrode.
 
Company Profile:
Carbo Graphite Industrial PTE. LTD is a leading group company in China that mainly produces and manages carbon metallurgical material products, and provides fast quotation, reliable quality, competitively priced products and as fast as possible delivery services in accordance with industrial standards and customer requirements. Founded in 1992 in Zhengzhou in central and eastern China. In order to play a greater role in the entire production and supply chain, we work closely with our customers. With more than 20 years of professional experience and expertise in the carbon metallurgy industry, the company is committed to research and development and provides a range of high-quality, innovative, and cost-effective carbon and metallurgical products and solutions. At present, the main products are graphite electrodes, electrode pastes, forged petroleum coke and refractory materials. The product line includes carbon materials, graphite materials, refractory materials and water treatment materials. With an annual output of 200,000 tons of electrode paste, 50,000 tons of graphite electrodes, 250,000 tons of calcined coke, 20,000 tons of refractory materials, etc.
 
  As China's leading supplier of carbon metallurgical materials, Carbo Graphite Industrial PTE. LTD. as a pilot enterprise under the Belt and Road Initiative, seizes development opportunities and exports first-class carbon and metallurgical products to the world as its mission to vigorously develop overseas markets. Our products have been exported to Asia, Africa, Middle East, South America and many other countries and regions, enjoying a good reputation.