Intermediate frequency electric furnace development in modern casting production

Intermediate frequency electric furnace development in modern casting production

Modern medium frequency electric furnace machinery manufacturing technology and the rapid development of metallurgical technology on casting quality, elaboration, and energy saving requirements, such as high performance of ductile iron castings, vermicular graphite cast iron and the application of aluminum alloy castings, high quality castings, makes the induction furnace is increasingly important in the position in modern casting production. All made and new foundry casting workshop, the fuss made or acquire induction furnace is usually in the first place. As a result, "" in the selection of induction furnace is a subject worth attention.
Efficient, reliable and flexible operation of the intermediate frequency induction furnace of the development of manufacturing technology in vigilance and establishing the important position of induction furnace in foundry production process has played a role cannot be underestimated. From the bottom and has nearly a century of compared to traditional power frequency induction furnace, whether from the technical performance and job performance or from the aspects of investment, medium frequency induction furnace is the undisputed dominance. That makes it rapidly changing since the late 80 s of last century is widely applied in developed countries such as Europe, America, basically replaced the traditional power frequency induction furnace in our country has gradually disappeared from the market, the existing power frequency induction furnace in foundry are gradually replaced by medium frequency induction furnace in this technical improvement.

Excellent performance of vacuum furnace

Excellent performance of vacuum furnace

The pressure inside the chamber of a stove or furnace smoke into industrial furnace is lower than the atmospheric pressure. Vacuum furnace heating power, the heated surface oxidation, no decarburization, small deformation, the mechanical performance is good. Use the vacuum furnace smelting metal to remove impurities, less finished pinhole, segregation of small, good quality. Vacuum furnace is suitable for the high quality, high purity, refractory metal melting and heating, such as tungsten, molybdenum, tantalum, niobium, titanium, heat-resistant alloy steel smelting and magnetic materials, electrical materials of high strength steel, stainless steel, tool steel and die steel, heat treatment.
Before and after vacuum furnace appeared in the 1930 s. In 1927 the United States made electrical material vacuum annealing furnace. Vacuum since 1953 arc furnace power consumption in industry have been used for melting titanium sponge. Before and after the '50 s vacuum induction furnace is widely applied in industry. In 1960 the United States developed oil quenching vacuum furnace.

Introduction of refractories in different position of induction melting furnace

Introduction of refractories in different position of induction melting furnace

The lining of introduction melting furnace is divided into four parts: furnace lid, furnace hearth, throat and and sensor. Especially throat,the most critical position’s refractory material directly affects the life and operating costs of the furnace.
1.Refractory material used in lid
The main effect of furnace lid is to reduce the heat loss of furnace, preventing the metal liquid splash, which requires the lid to be light weight, good insulation effect and anti-corrosion. At present, CCEWOOL ceramic fiber is light weight and low thermal conductivity, thus it is the most ideal refractory lining material. Due to the working temperature of furnace is below 800C, using steel nail or steel mesh to fix the blanket on lid
2.Refractory material used in hearth
The refractory material of hearth should use low porosity and high density CCEWOOL high alumina bricks.
3.Refractory material used in throat and sensor
The structure of throat and sensor is complicated, thus it mostly adopts unshaped refractory material. Castable uses high alumina refractory material, like corundum, mullite.

The difference between vacuum brazing furnace and vacuum induction furnace

The difference between vacuum brazing furnace and vacuum induction furnace

  Vacuum brazing furnace is in a vacuum environment to be heated objects in protective sintering furnace, its heating mode is more, such as resistance heating, induction heating, microwave heating, etc.
  Vacuum induction furnace is heated objects to make use of induction heating protective sintering furnace, can be divided into the power frequency, medium frequency, high-frequency, such as type, can be ascribed to a subclass of vacuum brazing furnace.

Vacuum induction furnace processing technology

Vacuum induction furnace processing technology

Vacuum furnace according to the structure can be divided into vertical and horizontal two series, the series is divided into vertical bell lift and lift the bottom tray. Horizontal series of single structure and front and rear double open the door to open the door again two kinds of structure. Furnace adopt water-cooled wall structures.
Heating equipment to protect the greenhouse adopts full metal type and compound two to choose from, all metal type of heat-resisting stainless steel and molybdenum screen; Compound of heat-resisting stainless steel, molybdenum screen and carbon felt, mullite fiber or silicate fiber composition. The specific choice depends on the user's process conditions and the requirement of process environment.
Heater is nichrome wire (belt), molybdenum wire (belt, bar), several types such as graphite, specific choice depends on the user's maximum temperature. Heater distribution have heating type and all-round heating two all around, to ensure that the user requirements for uniform temperature in the vacuum furnace type.
Cooling system has roots blower external loop structure, centrifugal fan centrifugal fan outside loop structure, cold wall circulate in several types such as the structure, meet the requirements of different cooling speed.
Vacuum system with pump + + mechanical pump, turbomolecular pump, turbomolecular pump, mechanical pump, diffusion pump, roots pump and mechanical pump, roots pump + mechanical pump, low temperature condensate pump + several types such as mechanical pump, according to the ultimate vacuum index selection.
Imported intelligent temperature controller, temperature control can realize the automatic control of heating, constant temperature, cooling function; With process curve storage function, can store several different process curve; Have litre cooling speed is adjustable and accurate clock function, can also according to the actual temperature and set temperature and other parameters; A vacuum furnace operation and power-fail protection function. Has a perfect alarm and protection.

Discharge phenomenon in vacuum induction melting furnace

Discharge phenomenon in vacuum induction melting furnace

So shall we talk about, it measures have? Decline in the power supply voltage, increasing turn distance; Choose reasonable furnace coil connection methods are can be reached by effect of electric field strength. However, because of the limitation of by the coil structure, often cannot increase turns distance. Therefore, combined method of coil to become crucial in the planning of induction furnace.
(1) small vacuum furnace induction melting furnace usually choose single induction coil, (can supply voltage) between two terminal voltage of the biggest, interturn voltage is very low. And essential way to prevent this kind of induction furnace discharge is a decline in the power supply voltage, with increased according to the specific conditions of turns distance from (usually turn distance in 5 ~ 10 mm, not too much or it will cause a decrease in the electrical power). In the process of planning practice, most small vacuum induction furnace power use 250 v voltage, will not cause in the process of producing discharge of [3].
(2) large and medium-sized vacuum induction melting furnace sometimes needs to choose the method to connect two or more coils - series (figure 2) (a) or parallel (as shown in figure 2 (b)). Two conditions interturn electric field intensity can present different situation, analysis is as follows.
(a) for the two induction coil in series, in a flash the polarity as shown. Two coil into the electrical terminals (A +), the electrical terminals (B -) adjacent, assume that the supply voltage RMS V. According to the principle of electrotechnics, the two adjacent terminals (A +, B -) between the voltage amplitude was flat, in the opposite direction. For a maximum of 2 V. Maximum instantaneous field strength for/air gap.
(b) for the two induction coil in parallel, in a flash the polarity as shown. Two coil into the electrical terminals (A +), (B +) adjacent, assume that the supply voltage RMS V. According to the principle of electrotechnics, the two adjacent terminals (A + B +) between the voltage amplitude was flat, direction. For a maximum of 0. The maximum instantaneous field intensity is zero. The above analysis of vacuum induction melting furnace discharge phenomenon.

Intermediate frequency electric furnace safety operation procedures

Intermediate frequency electric furnace safety operation procedures

1, check things out before blowing in electrical equipment, water cooling system, sensor brass etc are in good condition, otherwise prohibited furnace.
2, furnace melting in excess of the prescribed shall promptly repair. It is strictly prohibited in melting too deep inside the crucible for melting.
3, sending and furnace should have someone who's in charge, after sending it is forbidden to contact sensors and cables. On duty shall not leave post, pay attention to the sensor and external circumstance of crucible.
4, loading, should check harmful items such as burden in presence of flammable and explosive mixed with, if you have to remove timely, it is forbidden to cold and wet material directly add to the liquid steel, melted liquid filled with first division after it is forbidden to chunk is expected to join in case cover.
5, and tamped crucible, scrap iron, iron oxide are forbidden to mix, rammed crucible must be compact.
6, pouring fields and official pit furnace should have no obstacle, no water, in case the steel landing explode.
7, molten steel are not allowed to dress too full, hand carry bags when pouring, two of them should be conformed to walk should be smooth, not allowed to walk fast abrupt stop, after pouring yu gang in a designated place, it is forbidden to dump.
8, intermediate frequency generator room should be kept clean, it is strictly prohibited flammable and explosive goods and other debris into indoor, indoor smoking ban.

Principle of intermediate frequency furnace by what job

Principle of intermediate frequency furnace by what job

How medium frequency melting furnace works, what is the principle of intermediate frequency furnace? , for example, put a metal cylinder has alternating medium frequency current in induction coil, metal cylinder has no direct contact with induction coil, electric coil temperature is very low, but the surfaces are heated to redness, and even melt, and the redness and melting speed as long as adjust the size and the strength of the current frequency can be achieved. If the cylinder on the coil center, surrounding the cylinder temperature is the same, the cylinder heating and melting did not produce harmful gases, light environmental pollution.
Here is to introduce: medium frequency melting furnace is a kind of will power frequency 50 HZ alternating current into intermediate frequency (above 300 HZ and 20 k HZ) power supply device, the three-phase alternating current (ac) power frequency, after rectification into direct current, then laid adjustable intermediate frequency electric current, direct current supply by capacitance and induction coil in through the intermediate frequency alternating current, generate high density magnetic field lines in the induction coil, induction coil, and cutting in cheng fang of metal materials, produce a lot of eddy current in the metal materials. The vortex also has some properties of intermediate frequency electric current, i.e., the metal itself free electrons in the resistance of the metal body flow to generate heat.

Medium frequency melting furnace main characteristics

Medium frequency melting furnace main characteristics

Medium frequency melting furnace medium frequency power supply adopts solid-state IGBT inverter and power regulation, is the assurance of high reliability;
Medium frequency melting furnace equipment in the design the all-round protection function like over current protection, owe water protection, overheating protection, over-voltage protection, short circuit protection, open phase protection, etc., more than increase equipment reliability and convenient equipment maintenance work;
Medium frequency melting furnace equipment has a variety of display functions such as frequency display, voltage, current, power, according to make the equipment working condition direct, to design and capacitance induction coil regulation more guidance;
Medium frequency melting furnace super small volume, light weight, portable, covers an area of less than 1 square meters;
Medium frequency melting furnace 24 hours uninterrupted smelting capacity;
Intermediate frequency furnace energy saving energy saving, capable, electromagnetic stirring of molten material more uniform;
Medium frequency melting furnace convenient change different weight, different materials, different ways of the furnace body, to adapt to the requirements of various kinds of melting.