Some standard content:
Mechanical Industry Standard of the People's Republic of China
JB/T4280-1993
Medium Frequency Coreless Induction Furnace
Published on August 21, 1993
Implemented on October 1, 1993
Medium Frequency Coreless Induction Furnace
1 Subject Content and Scope of Application
Replaces JB4280-86
This standard specifies the varieties and specifications, technical performance, test methods, inspection rules, technical classification and ordering and supply requirements of medium frequency coreless induction furnaces (hereinafter referred to as medium frequency coreless furnaces). This standard is applicable to coreless induction melting furnaces and iron holding furnaces with a frequency higher than the industrial frequency by 50 (60) Hz and lower than 10000 Hz, a rated capacity of 0.01, 0.03, 0.05, 0.1, 0.15, 0.25, 0.5, 1, 1.5, 2, 3, 5, 7, 10, 15, 20, 25, 30 t, and powered by medium frequency power supply.
2 Reference standards
GB10066.1
GB10066.3
GB10067.1
GB10067.3
JB4086
3 Terms
Test methods for electric heating equipment General part
Test methods for electric heating equipment Coreless induction furnace Basic technical conditions for electric heating equipment General part Basic technical conditions for electric heating equipment Induction heating equipment Safety of electric heating equipment Part 1 General part Safety of electric heating equipment Part 3 Special requirements for induction and conductive heating equipment and induction melting equipment Technical conditions for medium frequency induction heating Sichuan electric control equipment Except for the definitions of the following terms. This standard adopts the terms specified in Chapter 3 of GB10066.3. 3.1 Rated capacity
The weight of liquid charge that the furnace can accommodate under normal working conditions as specified in the design of the medium frequency coreless furnace. 3.2 Rated frequency
The nominal frequency output by the medium frequency power supply device selected when designing the medium frequency coreless furnace. 3.3 Thermal stability of the furnace
The state of the furnace when all the power input to the furnace is used to compensate for its heat loss. If there is no special indication, it is generally in thermal stability after two consecutive furnace operations.
3.4 Rated operating voltage
The highest voltage across the induction coil in the oscillation circuit formed by the induction coil and the compensation capacitor group of the furnace. 3.5 Unit power consumption
The ratio of the total power (kW·h) supplied to the furnace from the input end of the industrial frequency power supply to the rated charge from the initial temperature to the rated temperature (including the heating of the molten or liquid charge) to the rated charge volume (t). 4 Product classification
4.1 Varieties and specifications
Medium frequency coreless furnaces can be divided into steel melting furnaces, iron melting furnaces, iron holding furnaces, steel melting furnaces, aluminum melting furnaces, gold melting furnaces, silver melting furnaces, etc. according to their uses. The varieties and specifications of melting pots and iron melting furnaces are shown in Table 1. Others can be determined by users and manufacturers based on the rated capacity level of this standard. Approved by the Ministry of Machinery Industry on August 21, 1993
Implemented on October 1, 1993
Rated capacity
Medium frequency power supply rated
Rated power consumption
100~150
100200
160~500
2501000
500~1500
750~1500
1000~2000||tt| |1500~2500
20003000
JB/T42801993
Main technical parameters of medium frequency coreless induction furnace
Actual power frequency
Li Chunshuwei
100G~2500
1000~25G0
1000~2500
500~1000
$00~1000
500~10 00
500~1000
Melting calcium steel 1600℃
Melt rate
Unit power consumption
Melting cast steel 1450℃
Melt rate
Unit power consumption
kw·h/t
Technical classification
Rated capacity
Medium frequency power supply rated power recommendation
JB/T4280-1993
Continued Table 1 Medium frequency Main technical parameters of centerless induction furnace Medium frequency source frequency
Recommended use
Smelting bamboo iron 1600℃
Melt rate
Unit power consumption
Melting fast iron 1450~
Melt rate
Unit power consumption
Technical classification
Note: ① The unit power consumption and melting rate (or increased productivity) of medium frequency centerless furnaces with capacity levels below 0.05t and above 7t are not specified and can be negotiated between the supplier and the demander.
③The parameters listed are powered by medium frequency power supply of grade brake tube. If powered by frequency conversion unit, the unit power consumption deviation is +10%, the melting rate deviation is -11%. 4.2 Product model
The product model of medium frequency coreless furnace consists of the following parts: GWOO-O/OO-
Design serial number
Technical grade code
Power supply device type: frequency converter - X, static frequency converter - J
Rated rate
Rated power kW
Rated capacity t
Use code: No indication for steel and iron, iron holding furnace B, copper - T, aluminum L, Gold J, Silver Y
Centerless induction furnace
4.3 Main parameters
Rated capacity, t:
Rated power.kW,
Rated frequency, Hz:
Rated working voltage, V:
Rated voltage of medium frequency power supply, V;
Rated temperature, C:
Melt rate, t/h or heating productivity, t/h; Unit power consumption, kw·h/t;
Cooling water pressure, MPa;
Cooling water consumption, m*/hs
Furnace body weight, t
Outer dimensions of guard body, mm.
5 Technical requirements
5.1 General requirements
JB/T4280-1993
The medium frequency coreless furnace shall comply with the relevant provisions of Chapter 5 of GB10067.1. 5.2 Supplementary requirements for design and manufacturing
5.2.1 Overall design
The medium frequency coreless furnace is mainly composed of the furnace body, tilting transmission device, operating console, busbar, capacitor cabinet (or combined with the medium frequency power supply device), medium frequency power supply device and cold water system. Generally, a set of medium frequency power supply device is equipped with one or two medium frequency coreless furnaces (one of which is a spare), and when equipped with two furnace bodies, a corresponding capacity of furnace reversing switch should be available. If the user does not need to spare the furnace body, it can be proposed according to Article 9.2. The furnace body is generally a vertical tiltable structure, the furnace tower is made of weak fire material (or coal crucible), the furnace cover on the upper part of the furnace body can be opened and closed, the movable part of the furnace body is installed on the fixed furnace frame, driven by hydraulic, electric or manual, and the medium frequency coreless furnace is usually installed on the floor or semi-underground.
The design of the medium frequency coreless furnace should take into account the rigidity of the overall assembly of the furnace body, the influence of full magnetism on the structural material, the electrical performance of the induction line diagram, the alarm to prevent leakage, water monitoring, etc. Its safety measures should be effective and reliable, and the output power of the medium frequency power supply should be able to be adjusted according to the requirements of various working conditions such as baking, melting and preservation. Under the premise of ensuring safety and convenient operation and maintenance, the busbar and soft cable of the oscillation circuit should be as short as possible to reduce line impedance and loss.
5.2.2 Tilting furnace frame
The tilting furnace frame is made of steel or aluminum alloy. The induction coil, magnetic pick and furnace frame are connected as a whole. The furnace frame should have sufficient rigidity and should be able to maintain stable operation when tilting with the maximum load. The furnace table panel should be tightly covered. When there are special requirements, they can be proposed according to Articles 9 and 2. 5.2.3 Fixed furnace frame
The fixed furnace frame should be able to support the weight of the furnace body (including the maximum load) and the force during the tilting of the furnace body. The bearing seat bottom plate and the fixed furnace frame, as well as the fixed furnace frame and the installation foundation should be firmly connected. When there are special requirements, they can be proposed according to Article 9.2. 5.2.4 Furnace lining
The lining of the medium frequency coreless furnace should comply with the requirements of Article 5.1.4 of GB10067.3, and its sequence should comply with the design size. The baking and sintering process of the furnace seal should be specified in the product manual.
5.2.5 External insulation layer and heat insulation layer
There should be an insulation layer and a heat insulation layer between the furnace lining and the induction coil. The insulation layer should be made of H-grade or above insulation material with reinforcement material, and the heat insulation layer should be made of insulation material with a working temperature not lower than 500℃. 5.2.6 Induction coil
The induction wire should comply with the provisions of 5.1.3, 5.1.3.1, 5.1.3.2 and 5.1.3.4.5.1.3.5 and the following provisions of GB10067.3. 5.2.6.1 The conductor material of the induction line should be a copper ridge or square or rectangular copper tube of not less than T2. Without safety inspection means, the copper tube is not allowed to be extended and welded. The welding of the connection plate and the tap connection plate should ensure conductivity and water channel Yang, and the tap position should be appropriate, connected, and easy to replace.
5.2.6.2 After the induction coil is wound and formed, it should be subjected to a water pressure test of 1.5 times the maximum working pressure, and there should be no seepage after 5 minutes. 3.2.6.3 After the induction coil is wound and formed, it should be insulated according to professional technology, and the heat-resistant insulation level of the insulation layer and insulating paint used should not be lower than Class B.
5.2.6.4 The manufacturing size deviation of the induction wire should meet the requirements of the design drawings. 5.2.6.5 Under normal use conditions, the service life of the induction wire (referring to insulation) for A, B, and C grade products shall not be less than 6000, 8800, and 12000 hours respectively.
5.2.7 Yoke
The yoke shall be made of silicon steel sheets, and its cutting area and length shall be able to limit the hysteresis flux and support the load of the induction wire, and at the same time, it shall be able to be firmly connected with the furnace body itself.
5.2.8 Furnace cover
JB/T4280-1993
1t and above medium frequency coreless furnaces shall have a movable furnace cover, on which an observation hole may be set, which can be opened and closed by manual or other power: the furnace stack below 1t can be determined by both parties according to needs. 5.2.9 Water cooling system
The water cooling system of the medium frequency coreless furnace can be an open or closed water supply system. The water cooling system should be equipped with water overflow, water pressure monitoring and protection links, and each branch should also be equipped with a flow regulating valve.
5.2.10 Transmission equipment
The medium frequency coreless furnace should be equipped with a tilting furnace transmission mechanism, and the operation should be uniform, stable, flexible and reliable. The tilting furnace movement is not allowed to be stuck, impacted or moved when the furnace is cold or hot. The maximum tilting furnace angle is 95°, and there should be a reliable limit device at the extreme position of the tilting furnace. The medium frequency coreless furnace generally adopts a hydraulic or intermediate transmission system, but a manual transmission system can be used for a small capacity medium frequency coreless furnace. The hydraulic system should be composed of an oil pump or an oil tank. A mesh oil filter or a magnetic oil filter should be installed at the oil return point in the oil tank to filter out impurities and rust in the oil wave. An air filter should be installed on the oil tank cover to prevent dust from entering the oil tank. The oil tank cover and the box body should be sealed. For easy maintenance, the oil pump and main auxiliary devices should be installed outside the oil tank. There should be no oil stagnation in the pipelines of the hydraulic system to prevent external accidents caused by the sudden splashing of molten metal.
The hydraulic system should withstand 1.5 times the maximum working pressure, 10 minutes for type test + 5 minutes for factory test, no leakage in any part of the pipeline, no deformation of the metal pipeline.
After the hydraulic system (or electric system) is assembled, the furnace operation test and type test should be carried out for 5 consecutive times under no-load and heavy-load (with counterweight) conditions. The factory test should be carried out for 5 consecutive times under no-load conditions. There should be no looseness or deformation, and the rotation should be flexible and reliable. When the hydraulic system is used to operate the furnace cover to open and close, the furnace cover should be opened or closed, and the operation should be smooth, flexible and reliable. In order to prevent the surrounding sand and dust and molten iron from contaminating the working surface of the oil cylinder of the liquid urine system, appropriate protective measures should be taken. 5.2.11 Medium frequency coreless furnace
5.2.11.1 The medium frequency power supply device should be equipped with a medium frequency power supply device. The power supply device should be able to meet the requirements of the furnace performance indicators. Its output power should be adjustable within the range of 10% to 100% to meet Different requirements for baking, melting and insulation. The rated power of the medium frequency power supply device is allowed to deviate by +5% while ensuring that the voltage of the compensation capacitor group of the vibration full circuit does not exceed the rated value.
5.2.11.2 The medium-frequency coreless furnace should be equipped with a compensation capacitor cabinet, with manual or automatic power factor adjustment. Manual adjustment is Class A, automatic adjustment is Class B, and automatic adjustment while maintaining power operation is Class C. 5.2.11.3 Medium-frequency coreless furnaces above 1t should have lining leakage current monitoring and furnace alarm devices. An alarm signal should be issued and the power supply should be automatically cut off before the furnace leaks.
5.3 Performance requirements
The performance of the medium-frequency coreless furnace shall comply with the relevant provisions of Article 5.2 of GB10067.3 and the following provisions Requirements. 5.3.1 Rated temperature
The rated temperature of the medium frequency coreless furnace is 1800℃ for the melting pot; 1450℃ for the molten iron, and the iron holding furnace is increased from 1350℃ to 1450℃ (i.e., a temperature increase of 100C). In actual operation, its rated temperature can be changed according to the process requirements. 5.3.2 Unit power consumption and melting rate
The unit power consumption and melting rate of the medium frequency coreless furnace and its technical classification shall comply with the provisions of Table 1. 5.3.3 Temperature rise
The surface temperature rise of each part of the medium frequency coreless furnace shall comply with the provisions of Table 2. 5.4 Safety requirements
Furnace frame, furnace shell, yoke
Bottom plate, cover
Hydraulic system Wei oil tank
JB/T4280-1993
Allowable surface temperature rise| |tt||The safety requirements for medium frequency coreless furnaces shall comply with the relevant provisions in GB5959.1 and GB5959.3 and the following supplementary provisions. When there are additional requirements, they can be proposed in accordance with Article 9.2.
5.4.1 The length of the water inlet and outlet hoses used for all induction coils and water-cooling cables under different working voltages shall be designed according to the requirement that the leakage current in a single branch is not greater than 20mA. The hose itself shall have sufficient electrical insulation performance and mechanical strength. 5.4.2 When the medium frequency coreless furnace is working normally, the electrical clearance and creepage distance between different charged parts and the ground shall comply with the provisions of Table 2 in JB4086.
5.4.3 Necessary protection nets shall be set up for the easily accessible places of all feeding parts of the medium frequency coreless furnace. The furnace frame, capacitor cabinet, medium frequency power supply device, operating console housing, etc. should be reliably grounded, and the grounding resistance value should not be greater than 45.4.4 In order to prevent accidents caused by sudden power outages and water outages, it should be clearly specified in the product manual that users should have a backup water source. When the cooling water stops accidentally, it should be able to be switched immediately.
5.5 Complete set requirements
The complete set range of the medium frequency coreless furnace specified by the supplier should be listed in the enterprise product standard, and should include the following items: 5.5.1
Furnace body;
Hydraulic or electric or manual tilting furnace transmission device; operating console;
Zhongying power supply device,
Capacitor cabinet (or combined with frequency conductor variable frequency device); tilting furnace switch (or combined with items): water-cooled soft cable:
Spare parts;
Factory documents include product manuals and necessary design drawings). The specific contents of the above items should be listed in the enterprise product standards, including models, specifications and quantities. If there are different requirements for the items specified by the supplier, they can be proposed in accordance with Article 9.2.
When the following accessories or devices are required to be provided, they can be proposed in accordance with Article 9.2, and their technical requirements shall be agreed upon by the supplier and the buyer. a.
Supporting busbar:
Electronic automatic weighing device and accessories:
Emergency device:
Tools for building and dismantling furnaces:
Water system and accessories;
Overflow measuring instrument and compensation wire.
Test method
The test method of the medium frequency coreless furnace shall be carried out in accordance with the relevant provisions of GB10066.1 and GB10066.3 and the following supplementary provisions. 6.1 The measurement of unit power consumption and melting rate shall be carried out in accordance with Article 5.8 of GB10066.3 and supplemented as follows: JB/T4280-1993 The test shall be carried out in a thermally stable state after two consecutive furnaces; a.
b. The steel melted in the medium frequency coreless furnace shall be ordinary medium carbon steel, and the iron melted shall be ordinary cast iron; the test charge shall be a combination of large and small pieces to make full use of the furnace space, and the charge surface shall be free of slag, sand, rust or oil, etc. The weight of the added charge or the additional charge weight shall enable the medium frequency source to output the maximum power, and the charge shall be added successively to the rated capacity; d During the test, the number and time of opening the furnace cover shall be minimized; e. The average value of three consecutive furnaces shall be taken. bzxZ.net
6.2 The measurement of charge temperature
shall be carried out in accordance with Article 5.11 of GB10066.3, and the thermocouple shall be inserted into the appropriate depth below the liquid surface. 6.3 Surface temperature rise products
The measurement points of surface temperature rise are as follows:
8. Furnace frame, shell, magnet, furnace bottom plate, furnace cover and any point on the outer surface: b. The outer surface of the oil tank of the hydraulic system;
C, any point on the outer surface of the busbar and the water-cooling cable connection end. Note: The outer surface part of the light shield and furnace cover close to the furnace mouth, within 100mm from the edge of the observation hole, is not within the measurement range. Measure with a surface thermometer with a measurement accuracy of not less than 2.5. 6.4 Inspection of leakage furnace alarm device
During the factory test, input the analog signal to observe whether the alarm operates normally. During the type test, it can be carried out according to the enterprise product standard. 7 Inspection rules and grade division
The inspection rules of medium frequency coreless furnace shall be in accordance with GBI0067.1. The relevant provisions of Chapter ? shall be followed. 7.1 The factory inspection items of the medium frequency coreless furnace are as follows: g. General inspection;
Safety inspection;
Furnace body assembly size inspection;
Inspection of the manufacturing quality of the induction coil:
Measurement of the electrical clearance between the induction line and the furnace shell: Measurement of the insulation resistance between the induction coil and the furnace shell: Measurement of the insulation resistance between the induction line and the magnetic field: Insulation withstand voltage test of the coreless furnace:
Pressure test of the hydraulic system:
Tilting operation test of the tilting furnace transmission mechanism: Water pressure test of the induction coil!
Inspection of the alarm interlock and the leakage alarm device; m.
Inspection of the catering parts, including the inspection of the model, specification, and factory qualification certificate; Supply range, including the inspection of the integrity of the factory technical documents; Packaging inspection.
7.2 The test items of medium frequency coreless furnace are as follows: a.
All factory inspection items, pressure test of hydraulic system:
Tilting test of tilting transmission mechanism; furnace charge temperature measurement;
Unit power consumption of furnace, melting rate measurement: surface temperature rise measurement;
Overflow measurement of cooling system;
Inspection of leakage alarm device:
Inspection after hot test.
7.3 Technical classification of medium frequency coreless furnace see 3. Technical classification
Ideal line cabinet
Medium frequency power supply device
Unit power consumption, melting rate
Reduction requirements
JB/T4280-1993
Clothes 3 Technical classification of medium frequency coreless furnace
According to the requirements of Article 5.2.6.5
According to the requirements of Article 5.2.11.2
According to the requirements of Article 5.3.2
According to the requirements of Article 5.5.1
8 Marking, packaging, transportation and storage
According to the requirements of Article 5.5.1 and
Article 5.5.2a
Marking, packaging, transportation and storage shall comply with the provisions of Chapter 8 of GB10067.1. 8.1
The following items shall be marked on the nameplate of the medium frequency coreless furnace: Product model and name:
Rated capacity, t
Rated working voltage, V;
Rated power, kW:
Rated frequency, Hz
Rated temperature, ℃:
Furnace weight, 1
Product number:
Standard number:
Date of publication:
Manufacturer name (country name shall be included for export products) Ordering and Supply
The ordering and supply of medium frequency coreless furnaces shall be in accordance with the provisions of Case 9 of GB10067.1: When the purchaser has the following special requirements, it may be proposed to the supplier, which shall be agreed upon by the supply and demand parties. ,
According to the requirements of Article 5.5.1 and
Article 5.5.2 a and e
different requirements for unit system, medium source medium voltage, power supply frequency (see Article 5.1.1.1 of GB10067.1); different requirements for the use environment (see Article 5.1.2 of GB10067.1); additional requirements for safety and environmental protection (see Article 5.1.5.1 of GB10067.1); different requirements for painting (see Article 5.2.7 of GB10067.1); special requirements for packaging (see Article 8.2 of GB10067.1); Different requirements for water system (see Article 5.1.3 of GB10067.1), no spare furnace body is required;
Different requirements for tilting furnace frame;
Different requirements for fixed furnace frame;
Different requirements for the supply items specified by the supplier; Requirement to provide supporting busbar:
Requirement to provide electronic automatic weighing device and accessories; m.
Requirement to provide emergency device +
Requirement to provide furnace building and dismantling tools;
Requirement to provide water system and accessories *
Requirement to provide temperature measuring instrument and compensation wire. Additional notes:
JB/T4280-1993
This standard is proposed and managed by the Hunan Traction Electrical Equipment Research Institute of the Ministry of Machinery Industry. This standard is drafted by the Hunan Traction Electrical Equipment Research Institute. 66
08cv L/al
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