30T Electric Arc Furnace

30T Electric Arc Furnace  

30T Electric Arc Furnace Introduction

The 30T electric arc furnace is designed with furnace cover rotation, top loading, and eccentric bottom tapping. The electrode lifting is automatically adjusted by a proportional valve and controlled by PLC.

Application of 30T Electric Arc Furnace

This 30T Electric Arc Furnace is used for ordinary structural steel, high-quality steel and advanced alloy structural steel.

30T Electric Arc Furnace Usage Conditions

 

Main Technical Parameters of 30T Electric Arc Furnace

     1. Rated capacity 30t
     2. Maximum steel tapping capacity: 40t (5t steel remaining)
     3.  Furnace shell inner diameter φ4300mm
     4. Tapping/slag tapping angle (maximum) 20°/12°
     5. Graphite electrode diameter φ400mm
     6. Graphite electrode distribution circle φ1100mm
     7. Maximum electrode stroke 3100mm
     8. Electrode lifting/lowering speed 6/4.5m/min
     9. Furnace cover lifting height 400mm
     10. Furnace lid rotation angle ~66°
     11. Hydraulic system: working pressure 12Mpa
               Working medium water-ethylene glycol
     12. Compressed air system: working pressure >0.4Mpa
                   Consumption 5m3/h
     13. Transformer: rated capacity 16 MVA
             Primary voltage 35KV
             Secondary voltage 430~342.5~220V 13 levels
             Secondary current 26917A
             Voltage regulating method: On-load electric voltage regulating
             Secondary terminal outlet method: Inner sealing △ side outlet
             Cooling method Oil-water cooler
     14. Short network: Impedance value ≤0.65+j2.7mΩ
             Three-phase unbalance coefficient ≤5%
     15. Cooling water system: inlet water pressure 0.5MPa (closed loop)
　　　　　　0.35Mpa (open loop)
　　　　       Water inlet temperature ≤35℃
                    Outlet water temperature ≤55℃
                    Consumption ~480m3/h
                    Water quality should comply with the requirements of Section 5.1.3.3 of the national standard GB10067.1~4-88"Basic Technical                    Conditions for Electric Heating Equipment", that is:
                 PH value 6～8
      16. Suspended solids <10mg/L
                 Chloride ion average <60 mg/L
                 Dissolvable solids <100mg/L
                 Conductivity ＜10□ s/cm
                 Total hardness <10 degrees (each degree of water is 10mgCaO per liter of water)

5. 30T electric arc furnace complete supply scope: (single unit)

The following materials are to be prepared by the user
a) Graphite electrodes and connectors
b) Refractory materials
c) Hydraulic medium

 

30T Electric Arc Furnace Equipment Overview

Operation mode of 30T electric arc furnace: one for left and one for right operation.

Furnace Tilting Mechanism:

The tilting mechanism of the 30T electric arc furnace consists of a track, a tilting cylinder, a cradle platform, a horizontal support mechanism and a bearing.
     
Furnace Body

 

The 30T electric arc furnace furnace body device consists of an upper furnace shell, a lower furnace shell, a water-cooling block, a furnace door mechanism, an eccentric bottom tapping mechanism, etc. The upper furnace shell is made of φ180x10 seamless steel pipes welded into a frame structure, the furnace wall is made of seamless steel pipes welded into water-cooled blocks installed horizontally, and the lower furnace shell is welded with steel plates.

 

Furnace Cover

The 30T electric arc furnace cover is a water-cooled tube structure with a refractory center cover and three electrode holes. The furnace cover is equipped with alloy feeding holes.

 

Rotating Frame and Furnace Cover Lifting Mechanism

The 30T electric arc furnace rotating frame serves as the support structure for the furnace cover and electrode lifting device. It is made of steel plates and shaped steel welded together. Its curved arm is a water-cooled structure. The lower part of the rotating frame bracket is provided with a joist for installing the lifting cylinder. The joists are designed as detachable structures for easy installation and transportation. The bracket of the rotating frame is located in the center and is connected to the supporting arm of the rotating device through a hinge with a rolling bearing.

 

Rotating Mechanism

The rotating mechanism is composed of a driving cylinder, a rotating drum bracket, a turntable bearing, a driving and restraining pull rod, etc. The above-mentioned components constituting the rotating device are connected to each other and then installed on the tilting platform to form a four-bar linkage mechanism to realize the compound movement of furnace lid movement and rotation.

 

Electrode Lifting Device

The device consists of an electrode lifting cylinder, a column, an electrode cross arm, an electrode clamping mechanism, an insulating component, etc.
The lifting cylinder is installed inside the column, with one end connected to the bracket and the other end connected to the bracket. The cylinder drives the column and drives the electrode cross arm to lift.

 

Water Cooling System

The cooling points of the 30T electric arc furnace water cooling system include the cooling of short mesh copper pipes, water-cooled cables, conductive cross arms and electrode chucks, spray rings, hydraulic systems, rotating support cylinders, rotating frames, water-cooled furnace lids, furnace bodies and other parts. Each circuit is equipped with a stop valve and a return water over-temperature alarm thermometer to facilitate the normal operation of the equipment. Equipment water pressure: 0.3Mpa (open loop), 0.5Mpa (closed loop); inlet water temperature ≤35℃; outlet water temperature ≤55℃ ; Cooling water consumption ~480m3/h.

 

Compressed Air System

The 30T electric arc furnace compressed air system supplies gas for the feeding cylinder. The system is mainly composed of pneumatic triple parts, solenoid valves, etc. The air inlet pressure is >0.4Mpa and the air consumption is 5m3/h. This system is used to complete the opening and closing of the cylinder of the alloy material slide tube and realize the function of adding alloy material into the furnace.

 

Furnace Bus bar System

As part of the electric furnace, it only refers to the section from the secondary outlet end of the electric furnace transformer to the large-section water-cooled cable. It is mainly composed of furnace bus bar compensator, copper tube, and large-section water-cooled cable.
One end of the bus bar compensator is connected to the secondary outlet end of the transformer; one end is connected to the copper pipe out of the wall. Its function is to isolate and absorb the adverse effects on the transformer caused by the vibration of the copper pipe out of the wall caused by strong current.

 

Electric Furnace Transformer

This electric furnace is equipped with HSSPZ-16MVA/35KV special transformer. It directly reduces the user's 35KV high-voltage power grid to the operating voltage of the electric furnace. Its structure is secondary internal sealing, △ side outlet, water-cooled secondary side terminal structure. 13-level on-load electric pressure regulation, forced circulating water cooling (OFWF) using strong oil circulating water cooler.

 

Installation and Debugging

 

When the electric furnace leaves the factory, its components, components and parts are packaged and shipped. Related accessories and spare parts are also shipped with the product. Each component has been adjusted separately before leaving the factory, and the user assembles and debugs it one by one.