The main indexes reflecting the quality and performance of GRAPHITE ELECTRODE are: volume density db, resistivity, flexural strength, elastic modulus E, coefficient of thermal expansion, and ash content A%.

Main indexes reflecting the quality and performance of Graphite Electrode

 The main indexes reflecting the quality and performance of GRAPHITE ELECTRODE are: volume density db, resistivity, flexural strength, elastic modulus E, coefficient of thermal expansion, and ash content A%.

According to the differences in these indicators and the differences in raw materials and manufacturing processes, the national standard (YB/T 4088/89/90-2000) divides the GRAPHITE ELECTRODE into three types: ordinary power GRAPHITE ELECTRODE (RP), high power GRAPHITE ELECTRODE (HP) and ultra-high power GRAPHITE ELECTRODE (UHP). After that, the GRAPHITE ELECTRODE manufacturer added two kinds of high density GRAPHITE ELECTRODE (HD) and quasi-ultra-high GRAPHITE ELECTRODE (SHP) according to the user's demand.

The volume density is the ratio of the mass of the GRAPHITE ELECTRODE sample to its volume. Unit g/cm3, the larger the volume density is, the denser the electrode is, which is positively correlated with the strength and antioxidant properties. Generally speaking, the larger the volume density of the electrode of the same variety is, the lower the resistivity is.

The ways to improve the volume density are: adjust the formula, increase the amount of small grain and powder, use the coke with high true density, use the pitch with high coking value and increase The Times of impregnation：

Resistivity is the parameter to measure the conductivity of the electrode, is refers to the current through a conductor, a conductor that resistance to the flow of electricity a nature, value is equal to the length of 1 m, cross-sectional area of 1 m2 of conductor in a certain temperature under the condition of resistance, unit mu Ω m..

The lower the resistivity, the better the conductivity and the lower the consumption of the electrode in use.

The ways to reduce the resistivity are: using high quality raw materials, increasing the volume density of products, increasing the graphitization temperature, etc.

Flexural strength is a parameter that characterizes the mechanical properties of graphite material, also known as flexural strength. It refers to the ultimate resistance capacity of an object from bending to breaking moment when the external force is perpendicular to the axis of the object. The unit is MPa.

The strength of graphite material is significantly different from that of other metals and nonmetals. Its strength increases with the increase of temperature, and reaches the maximum at 2000-2500 ℃, which is 1.8-2 times of the normal temperature, and then decreases.

High - strength electrode, joint, in the use of the more difficult to break.

The way to improve the flexural strength is to reduce the size of coke in the formula, improve the strength of carbonaceous materials, improve the volume density of products, reduce the internal defects of products, etc.

Elastic modulus is an important aspect of mechanical properties, and it is an index to measure the elastic deformation capacity of materials. It refers to the ratio of stress and strain within the elastic deformation range of materials, and the unit is GPa.

The larger the elastic modulus is, the greater the stress required to produce a certain elastic deformation. Simply speaking, the larger the elastic modulus is, the more brittle the material is, and the smaller the elastic modulus is, the more flexible the material is.

The way to reduce the coefficient of thermal expansion: it is mainly decided by the inherent properties of the raw material to use good quality raw materials, the formula to use a larger particle size formula or increase the amount of large particles (but will make the product density and strength reduced).

Ash refers to the content of other solid elements in the product except carbon and graphite.

The ash content in the GRAPHITE ELECTRODE is mainly affected by the ash size of the raw material used. The ash content of the needle coke of petroleum coke is relatively low, so the ash content of the GRAPHITE ELECTRODE is generally not more than 0.5%, and the ash content within 1% has no obvious effect on steel making, but the impurity elements in the ash content will reduce the antioxidant performance of the electrode.

Thermal vibration resistance factor is a parameter that characterizes the thermal vibration resistance. Thermal vibration resistance is a property of the material itself, which describes a property of the material to withstand rapid cooling and rapid heating. In other words, it is a property of the material to resist fragmentation under a certain temperature gradient, and it is a very important comprehensive factor affecting the use of electrodes.

K -- thermal shock resistance factor, w/m;

α-- tensile strength, MPa;

E -- modulus of elasticity, MPa;

λ-- thermal conductivity, w/m times k;

Coefficient of thermal expansion, 1/K K is a relative value, the larger the value, the stronger the resistance to thermal vibration.

The K value of the GRAPHITE ELECTRODE has a high correlation with its performance in the arc furnace, that is, the higher K value corresponds to the lower breakage and fracture of the electrode.