Customized well type annealing furnace for bright annealing treatment of copper bars, aluminum alloys, copper alloys

Ⅰ．Application

With the help of the gas of CO₂ or N_2, The periodic vacuum annealing furnaces makes the non-ferrous metals and black metals heated without oxidizing, thereby to enhance the temperature uniformity and fast the speed of temperature increase. There furnaces are suitable for bright annealing treatment of high required tensile strength, uniform elongation materials such as copper bars, aluminum alloys, copper alloys, multi-element alloys etc.

Ⅱ．Main Technical Parameters

(a)Inner dimension of the furnace:Ф1000*1900mm (140kw)

(b)Wire coin dimension:Ф800*600mm

(c)Occupied dimension: See the drawing

(d)Rated power:140kw/set

(e)Rated voltage & frequency:380V/50HZ

(f)Operating temperature: 600℃

(g)Rated highest temperature:650℃

Ⅲ. Introduction of the structure

• Furnace body

The furnace body is made of thermal-protective furnace shell(thermal insulation materials) with heating elements in the wall of furnace.

• The furnace shell is made of structural steel(S=3-5mm).
• The furnace lining is made of fiber block with good thermal-protective condition. The temperature of furnace wall ≤50℃.
• The furnace wall is made of light refractory brick or fiber block.
• The heating element consists of a Cr20Ni80 electrically heated material with a flat strip bent into an m-type holding hook on the inner wall of the furnace.

• The furnace inner tank

It is made of stainless steel sheet(S=10mm), and the bottom is pot bottom style. The furnace cover and flange is made of steel processing(S=30mmQ235) by Lathe, and sealed with nitrile - butadiene rubber.

• Electric cabinet

Three - zone temperature control,

PID intelligent temperature controller,

A set of control mode,

Power regulator output.

Ⅳ. Installation

• Generally, the complete set of electric furnace has been installed.User should prepare the ground treatment to make sure the ground is hard enough to install the furnace according to the overall dimensions of the furnace.

(b) After the electric furnace is in place, connect the outside line with the electric control cabinet, then connect the electric control cabinet with the furnace, and test the circuit and the instruments finally.

• Connect the water-cooled tube, the above hole is for water outlet, the below hole is for water inlet, then test whether the water-cooled tube is connected correctly, whether the water volume and air pressure is in normal (the normal water pressure is over 2㎏), whether the water outlet and water inlet is working normally(working at same time).
• The shell of the furnace and the electric cabinet should connected with the ground to ensure safe working conditions.

Ⅴ. Furnace drying

200℃ constant temperature 6 hours

400℃ constant temperature 6 hours

600℃ constant temperature 6 hours

800℃ constant temperature 6 hours

• Remark:Circulating water is a must in furnace drying, or don’t install the sealing ring.

Ⅵ. Operation

• The operator must know the structures of the furnace and the accessory equipment, master the electric circuit and the connection of the water-cooled tubes.
• The insulation condition of the heating elements,shells and furnace must be carefully and thoroughly checked before power supplied and after maintenance. The operator must confirmed all the conditions are good before use it.

• Check the electrical connector, wire connection are all in correct connection before supplying power, the furnace inner tank shall be water cooled firstly, the fan and the furnace shall be separately pumped, and the water shall not be connected in series. The furnace can only be started after the cooling water supply systems is worked normally, then the electric furnace begins to heat up.

(d) After the heat preservation is over, cut off the heating power of the furnace, the fan will continue to operate, and the meter will still be energized. When the furnace temperature < 250 ℃, hoisting the furnace inner tank out of the furnace wall, the fan continue to work, when the temperature of the furnace inner tank< 100 ℃, the fan and the water supply can be stopped.

Warning: Never stop the fan and water supply during the heating process.

• Bring the parts out of the furnace(hoist the inner tank out) only when the temperature of the inner tank＜40℃ (because the oxidizing temperature of copper is 70℃, the surface temperature of the parts is low, but the center temperature of the parts is still high,when the parts out of the furnace, the center of the parts will be oxidized if the center temperature of parts is higher than 70℃, especially in summer and rainy season, please wait for more time to hoist out the inner tank to make sure the temperature is as lower as possible.
• Operation Orders

Put the inner tank into the furnace(put the parts into the inner tank firstly)——screw up the nuts (screw the nuts relatively)——pumping vacuum to make the air pressure is 0.1Mpa(about 20 min)——screw up the nuts again(check whether they were tightened),inflate the protective gas(CO₂ or N₂)(make sure the purity of the CO₂ or N₂ ,otherwise, the impure gas will affect the brightness of the parts surface.)as much as the scale level(generally 0.05-0.1Mpa)——Put the inner tank into the furnace(check all the joints of the instruments and valves to make sure there’s no gas leakage)——Connect the cooling water of the Fan and inner tank(check if the cooling systems is normally worked),then start on the electric power, the furnace will begin to heat, the operators should never leave the furnace, operate the furnace according to the orders strictly and record the temperature rising time, heat preservation time, cooling time, and watch whether the cooling water and the pressure instrument is normally worked. If there’s any abnormality, the operator should take relative remedial action(Right remedial action is a must, otherwise, may cause some accident)-- after the holding time finished, the instruments, the fan and the cooling water should not be stopped -- the inner tank is hoisted from the furnace wall, it should be cooled naturally or cooled by an air-cooler, at the same time, the cooling water still should not be stopped because the temperature of the inner furnace is still higher than the heat-resistance of the rubber sealing ring -- the parts are taken out of the inner tank(the temperature of the inner furnace ＜40℃) ,then the parts will be bright and meet the requirement.

• Warnings and Relative Remedial Action

• Before heating the furnace, tighten up the nuts or re-connect the equipment if finding air leakage; Continuously fill up the protective gas urgently until the air pressure ≥0.1Mpa and keep filling gas till the parts are finished heat-treatment if the instrument meter value is lower than the standard requirement. If the gas is used up, use a vacuum pump continuously to pump till the parts are finished heat-treatment.

• If finding water supply is break or intermittent water, increase the cooling water flow, or add water pumps to supply water in order to increase the water pressure and water volume, the water pressure should be over 2kg.
• If there’s an electrical problems, check the electrical problems or ask an electrician to solve the problems.
• To solve the circulating fan problems according to the Fan Instructions.

Ⅶ. Maintenance and Repair

• Always keep the cleanness of using environment, no dust on the power components, no water around the furnace on the ground, rain-proof.
• Regularly clean up the sundries in the furnace inner tank and furnace wall, use alcohol to scrub the inner tank and the insulating cover.
• Be careful to avoid the inner tank collides with the furnace body when putting it into the furnace, keep smooth and steady and vertically. Put the parts onto the loading shelf and use the loading shelf to put the parts into the inner tank.
• The instrument and meter should be inspected regularly, and the connection and sealing shall be checked frequently. If found problems, it should be timely repaired.
• Check whether the motor and reducer operate normally, and whether the furnace cooling system is working normally, if any obstruction is found, it should be timely repaired.
• The furnace, fan should be maintained daily and monthly. When stopping use the furnace, a total maintenance should be done and a general maintenance regulations is a must.