What is eaf graphite electrodes? eaf graphite electrode consumption
By:Yvonne Jan 22, 2021
EAF graphite electrodes is primarily used in electric arc furnaces for the steel production process and also used in the refinement of steel and similar smelting processes.
What is eaf graphite electrodes?
EAF graphite electrodes are made of mixed petroleum coke and coal pitch, to be extruded, baked, impregnated, graphitized and machined for use as conductive material on EAF (Electric Arc Furnace) and LF (Ladle Furnace) for steelmaking.
Eaf graphite electrodes are composed of rod and nipple
Graphite electrode has many advantages that makes it used widely.
• Easy to machine.
• Very resistant to thermal shock.
• It has a low coefficient of thermal expansion (3 times lower than copper) which guarantees stability of electrode geometry during electro discharge machining.
• Available in large blocks.
• It does not melt, but goes directly from the solid state to the gaseous at 3,400°C,
• Which reduces wear.
• Its density is 5 times lower than that of copper, which results in lighter electrodes.
• It provides a higher metal removal rate than copper with less wear.
• It has the unique characteristic that the wear ratio tends to decrease as the peak current increases.
► Eaf graphite electrode consumption
The consumption of graphite electrodes is related to the use of EAF steelmaking and the quality of graphite electrodes. Usually, 2 kilograms of graphite electrodes are consumed to melt one ton of steel, which accounts for a small proportion of steelmaking costs. Under all the same conditions, the larger the discharge current during steel making, the more consumption of the graphite electrode.
The following formula is used to calculate the end and side consumption of the graphite electrode:
Normal consumption of graphite electrodes: CE=Cγ+Cs（end and side consumption）
Front end consumption: Cγ=Vγ•TOntap/W,Vγ=Kγ•I2/dnγ
TOntap——EAF power supply time,h.
W——EAF tapping weight, t.
Vγ——Consumption speed of electrode end,kg/h.
Kγ——End consumption constant (Bowman gives Kγ=0.0361 and n is usually 0.58 for AC arc furnace).
I——Arc current intensity, kA.
dγ——Electrode end diameter, m.
TTop-Top——Electric furnace smelting cycle, h.
W——EAF tapping weight, t.
Vs——Electrode side consumption speed, kg/h.
Ks——Oxidation consumption rate, kg/(m2•h).
S——Oxidation surface area in EAF, m2.
The influence of 60t EAF current on the consumption of graphite electrode at different smelting time：
Table 1 Influence of current on electrode single consumption and smelting time