Some standard content:
ICS25.180.10
Machinery Industry Standard of the People's Republic of China
JB/T4280--2004
Replaces JB/T4280-1993
Medium frequency coreless induction furnace
Medium frequency coreless induction furnace2004-03-12 Issued
Implementation on 2004-08-01
Issued by the National Development and Reform Commission of the People's Republic of China
Normative reference documents
3 Terms and definitions
4 Product classification.
4.1 Varieties and specifications
Product model,
Main parameters
Technical requirements
General requirements,
Supplementary requirements for design and manufacture
Performance requirements..
Safety requirements,
Complete set requirements,
Test methods
Measurement of unit power consumption and melting rate
Measurement of component surface temperature rise
Inspection of furnace alarm device.
Inspection rules..
Marking, packaging, transportation and storage
Ordering and supply
Table 1 Recommended values of rated power and rated frequency of medium-frequency coreless induction furnace for melting iron (steel) JB/T4280-2004
This standard replaces JB/T4280-1993.
Compared with JB/T4280-1993, the main changes of this standard are as follows: JB/T4280-2004
Scope of application, it is stipulated that the medium frequency coreless furnace is powered by a semiconductor medium frequency power supply (see Chapter 1); a pair of molten iron (steel). The recommended range of rated power and the recommended value of rated frequency of each specification of the medium frequency coreless furnace have been modified and supplemented (see Table 1);
-The product model takes into account the situation of the holding furnace and cancels the technical level code, and adds the enterprise code (see 4.2): the content of a set of power supply supplying power to multiple furnaces at the same time is supplemented (see 5.2.1): a pair of tilting furnace frames, supplemented with "frame structure" (see 5.2.2): supplemented with the furnace lining push-out device (see 5.2.4) and put forward corresponding requirements (see 5.2.5); - The prohibition of using asbestos-containing materials (see 5.2.5) - The original classification regulations for the service life of the induction coil have been cancelled, but the original minimum requirements have been retained, and the structural requirements for increasing the strength of the induction coil have been supplemented (see 5.2.6) - New requirements for smoke exhaust and dust removal devices have been added (see 5.2.8) - For large-capacity medium-frequency coreless furnaces, a back-tilting function has been added (see 5.2.10) - For medium-frequency power supply devices, the matching requirements for the power supply device and the furnace load, the regulations on the power output state during smelting, and the requirements for configuring a computer process monitoring system, a rectifier transformer and a harmonic absorption device when necessary have been added (see 5.2.11) - The unit power consumption, melting rate and heating rate of the medium-frequency coreless furnace (applicable to holding furnaces) are changed to be specified in the enterprise product standards (see 5.3.2);| |tt||-Add the corresponding requirements for complete sets (see 5.5): 1. Cancel the provisions on technical classification (see original 7.3). This standard is proposed by the China Machinery Industry Federation. This standard is under the jurisdiction of the National Technical Committee for Standardization of Industrial Electric Heating Equipment (SACTC121). The drafting units of this standard: Xi'an Electric Furnace Research Institute, Xiangtan Electric Motor Co., Ltd., Wuxi Wanli Electric Furnace Co., Ltd., Suzhou Industrial Park Zhenhao Electric Furnace Co., Ltd., Shaanxi Haiyi Electric Furnace Co., Ltd. The main drafters of this standard: Ge Huashan, Zeng Zhaoxiang, Jia Shunian, Zhu Xingfa, Guo Xinshe. The previous versions of the standards replaced by this standard are: -JB24161978, JB4280-1986, JB/T4280-1993. 1 Scope
Medium frequency non-core inductor |tt||JB/T4280—2004
This standard specifies the specifications, technical performance, safety requirements, test methods, inspection rules, 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 holding furnaces for melting ferrous and non-ferrous metals and their alloys, which have a frequency higher than the power frequency of 50 (60) Hz and lower than or equal to 10000 Hz and a rated capacity of 0.01t, 0.03t, 0.05t, 0.1t, 0.15t, 0.25t, 0.5t, 1t, 1.5t, 2t, 3t, 5t, 7t, 10t, 15t, 20t, 25t, 30t, 35t, 40t, 50t, 60t and are powered by semiconductor medium frequency power supplies. Note: The above rated capacity specifications refer to smelting ferrous metals. For non-ferrous metals and their alloys, they should be the corresponding capacity when the volume is the same. 2 Normative reference documents
The clauses in the following documents become the clauses of this standard through reference in this standard. For all referenced documents with dates, all subsequent amendments (excluding errata) or revisions are not applicable to this standard. However, the parties who reach an agreement based on this standard are encouraged to study whether the latest versions of these documents can be used. For all referenced documents without dates, the latest versions are applicable to this standard. GB/T10066.1—2004 Test methods for electric heating equipment Part 1: General part (IEC60398: 1999, MOD) GB/T10066.3—2004 Test methods for electric heating equipment Part 3: Coreless induction furnace (IEC60646: 1992, MOD) GB/T10067.1—1988 Basic technical conditions for electric heating equipment Part 1: General part GB/T10067.31988 Basic technical conditions for electric heating equipment Part 3: Induction electric heating equipment GB5959.3 Safety of electric heating equipment Part 3: Particular requirements for induction and conductive heating equipment and induction melting equipment (GB5959.3-1988, eqvIEC60519-3:1985) JB/T7110-1993 Electric heating capacitors
JB/T8669-1997 Semiconductor frequency converter for medium frequency induction heating 3 Terms and definitions
The terms and definitions established in Chapter 3 of GBT10066.3-2004 and the following terms and definitions apply to this standard. 3.1
Rated capacity ratedcapacity
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 and marked on the nameplate. 3.2
Rated frequency ratedfrequency
The nominal frequency output by the medium frequency power supply device, as specified in the design of the medium frequency coreless furnace and marked on the nameplate. 3.3
Rated working voltage ratedworkingvoltageThe voltage across the induction line diagram in the oscillation circuit composed of the induction line circle of the furnace and the compensation capacitor group, which is specified in the design of the medium-frequency coreless furnace and marked on the nameplate.
4 Product classification
4.1 Varieties and specifications
The medium-frequency coreless furnace can be divided into steel melting furnace, iron melting furnace, iron insulation furnace, copper melting furnace, aluminum melting furnace, gold melting furnace, silver melting furnace and other varieties according to the purpose and the material of the molten material. The specifications of steel melting and iron melting furnaces and their recommended rated power and rated frequency are shown in Table 1. Other varieties can be based on this standard-
JB/T4280--2004
The rated capacity level is determined by the user and the manufacturer. Table 1 Recommended values of rated power and rated frequency of medium-frequency coreless induction furnace for melting iron (steel) Rated capacity
4.2 Product model
Recommended rated power
50~100
100~160
100-200
160-250
250-500
500-1000
750-1500
Recommended rated frequency
4000, 8000
2500, 4000
1000, 2500www.bzxz.net
1000, 2500
1000, 2500
500, 1000
500, 1000
The model of medium frequency coreless furnace consists of the following parts:G
4.3 Main parameters
a) Rated capacity, in t:
b) Rated power, in kW:
c) Rated frequency, in Hz;
d) Rated working voltage, in V:
e) Rated voltage of medium frequency power supply, in V: f) Rated temperature, in ℃;
g) Melting rate or heating rate, in h: h) Unit power consumption, in kW·h/t: i) Cooling water pressure, in MPa:
j) Cooling water flow, in m/m:
k) Furnace weight, in t;
Rated capacity
Enterprise code
Modification code
Recommended rated power
1000-2000||tt ||1500-2500
2500~4000
3000-5500
4000-8000
5000~12000
6000~16000
7500-20000
9000-24000
Rated frequency, unit is kHz
Rated power, in kW
Rated capacity, in t
Recommended rated frequency
500, 1000
150, 250, 500
150, 250
150, 250
Code for melted material (in Chinese phonetic letters) No code - steel, Qin. T - copper and its alloys, L aluminum and its alloys·J - gold, Y silver
(Chinese phonetic letters) Only applicable to holding furnaces (Chinese phonetic letters) Coreless induction furnace
1) Overall dimensions of the furnace body, in mm.
5 Technical requirements
, 5.1 General requirements
JB/T4280—2004
The medium frequency coreless furnace shall comply with the relevant provisions of Chapter 5 of GB/T10067.3-1988. When there is a difference between the provisions of this standard and this standard, this standard shall prevail.
5.2 Supplementary requirements for design and manufacturing
5.2.1 Overall design
The medium frequency coreless furnace is mainly composed of a furnace body, a tilting furnace transmission device, an operating console, a busbar, a capacitor cabinet (or combined with a medium frequency power supply device), a medium frequency power supply device and a cooling water system. Generally, a set of medium frequency power supply devices is equipped with one or two medium frequency coreless furnaces (one of which is used for melting, and the other is used as a standby or for simultaneous insulation, pouring and charging operations). It can also be equipped with more furnace bodies, such as two for simultaneous melting and the other for insulation, pouring and charging, to improve productivity. If a corresponding furnace change switch is required when multiple furnace bodies are equipped, it can be proposed according to 9.2.
The furnace body is generally a vertical tiltable structure, the furnace chamber is a crucible or other type of crucible made of refractory materials, the furnace cover on the upper part of the furnace body can be opened and closed, and the tiltable part of the furnace body is installed on a fixed furnace frame, which is tilted by hydraulic, electric or manual. The medium frequency coreless furnace is usually installed on the floor or semi-underground.
The design of the medium frequency coreless furnace should focus on the rigidity of the overall assembly of the furnace body, the influence of leakage magnetic field on the structural material, the electrical performance of the induction coil, the leakage furnace alarm, the water channel monitoring, etc., and its safety measures should be effective and reliable. The output power of the medium frequency power supply should be able to be adjusted according to the needs of various working conditions such as furnace drying, melting and insulation: when multiple furnace bodies are running at the same time, the power distribution of each furnace should be able to be adjusted according to the process requirements. Under the premise of ensuring safety and operation and maintenance convenience, the busbar and soft cable of the oscillation circuit of the medium frequency coreless furnace should be as short as possible to reduce line impedance and loss. 5.2.2 Tilting furnace frame
The tilting furnace frame is a steel or aluminum alloy furnace shell structure or frame structure, and the induction coil and yoke are connected to it as a whole. The tilting 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. 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 when the furnace body is tilted. 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. 5.2.4 Crucible and its furnace village
The crucible lining thickness of the medium frequency coreless furnace should meet the design size, and the ramming, baking and sintering of the furnace lining should be strictly operated according to the process provided by the refractory material manufacturer. When the user needs to push out the furnace lining, it can be proposed according to 9.2. The requirements for the conductive material crucible can be specified in the enterprise product standard or agreed upon by the user and the manufacturer.
5.2.5 Insulation layer and heat insulation layer outside the ground
There should be an insulation layer of insulation material above H grade and a heat insulation layer of thermal insulation material with working temperature not less than 500℃ between the furnace lining and the induction coil. When the furnace village is required to be pushed out as a whole, the loose layer of the furnace lining should be considered. It is forbidden to use materials containing asbestos. 5.2.6 Induction coil
The induction coil shall comply with 5.1.3.1, 5.1.3.2, 5.1.3.4 and 5.1.3.5 and the following provisions in GB/T10067.31988. 5.2.6.1 The conductor material of the induction coil shall be a round copper tube or a square or rectangular steel tube not less than T2. When the copper tube must be welded and lengthened due to the length specification, the corresponding welding process and strict inspection rules shall be formulated to ensure reliable conductivity and no leakage. The welding of the connecting plate shall ensure conductivity and smooth waterway.
5.2.6.2 After the induction coil is wound and formed, it shall be subjected to a water pressure test of 1.5 times the maximum working pressure, and there shall be no leakage for 5 minutes. 5.2.6.3 After the induction coil is wound and formed, it shall be insulated according to professional technology, and the heat-resistant insulation grade of the insulation layer and insulating paint used shall not be lower than Class B.
5.2.6.4 The manufacturing dimensional deviation of the induction coil shall comply with the requirements of the design drawings. 5.2.6.5 The induction coil and its plaque shall be fixed and positioned by solid structural support parts, yokes and pull rods to enhance rigidity so that it will not deform or move during operation.
JB/T4280—2004
5.2.6.6 Under normal use conditions, the service life of the induction coil (referring to insulation) shall not be less than 6000h. 5.2.7 Magnetic Yoke
The yoke shall be made of stacked silicon steel sheets, and its cross-sectional area and length shall be able to limit the magnetic flux and support the load of the induction coil, and shall be fastened to the furnace body as a whole.
5.2.8 Furnace Cover and Smoke and Dust Removal Device
It and above medium frequency coreless furnaces shall have a removable furnace cover, on which an observation hole may be provided, which can be opened and closed manually or by other power: The furnace cover of medium frequency coreless furnaces below It may be determined by both the supplier and the buyer as needed. When necessary, smoke and dust removal devices shall be provided for large capacity medium frequency coreless furnaces and may be proposed in accordance with 9.2.
5.2.9 Water Cooling System
The water cooling system of the medium frequency coreless furnace may be an open or closed circulating water supply system. The water cooling system shall be equipped with water temperature and water pressure monitoring and protection links, and each branch shall also be equipped with a flow regulating post. 5.2.10 Transmission device
The medium frequency coreless furnace should be equipped with a transmission mechanism for tilting the furnace and opening and closing the furnace cover, and the operation should be uniform, stable, flexible and reliable. The tilting movement should not be stuck, impacted or thrashed when the furnace is cold or hot, and the maximum tilting angle is 95°. For large-capacity medium frequency coreless furnaces, when a back tilting function is required for slag removal, it can be proposed according to 9.2. There should be a reliable limit device at the extreme position of the tilting furnace. Medium frequency coreless furnaces generally use hydraulic or electric transmission systems, but manual transmission systems can also be used for small-capacity medium frequency coreless furnaces. The hydraulic system should consist of a hydraulic pump and 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. An air filter should be installed on the oil tank cover to prevent dust from entering the oil tank, and the oil tank cover and the tank body should be sealed. For easy maintenance, the hydraulic pump and main auxiliary devices should be installed outside the oil tank. There should be no oil leakage in the pipelines of each part of the hydraulic system to prevent accidents caused by accidental splashing of molten metal.
The hydraulic system should be able to withstand a test of 1.5 times the maximum working pressure. The pressure should be maintained for 10 minutes during the type test and for 5 minutes during the delivery test. There should be no leakage in any part of the pipeline and no deformation of the metal pipe. After the hydraulic system (or electric system) is assembled, a furnace tilting operation test should be carried out. The type test should be operated continuously for 5 times under no-load and heavy-load (with counterweight) conditions, and the factory test should be operated continuously for 5 times under no-load conditions. There should be no looseness or deformation, and the rotation should be flexible, smooth and reliable.
When the hydraulic system is used to operate the furnace cover to open and close, the operation should be smooth, flexible and reliable. In order to prevent the sand and dust in the surrounding environment and molten iron from contaminating the working surface of the hydraulic cylinder of the hydraulic system, appropriate protective measures should be taken. 5.2.11 Medium frequency power supply device
5.2.11.1 The medium frequency coreless furnace shall be equipped with a semiconductor medium frequency power supply device that complies with JB/T8669-1997. The power supply device shall have a good match with the furnace load circuit and shall be able to meet the requirements of the furnace performance indicators. Its output power shall be adjustable within the range of 10% to 100% to meet the different requirements of furnace baking, melting and insulation. Its operating frequency range shall correspond to the rated frequency. The rated power of the medium frequency power supply device shall have an allowable deviation of +5% while ensuring that the voltage of the oscillation circuit compensation capacitor group does not exceed the rated value. 5.2.11.2 The medium frequency coreless induction furnace shall be equipped with a compensation capacitor cabinet. The power factor of the load circuit shall be automatically adjusted and shall not be lower than the provisions of its product standard. The compensation capacitor shall comply with the provisions of JB/T7110-1993. 5.2.11.3 The medium frequency power supply device configured for the medium frequency coreless furnace shall operate at a constant rated power for most of the smelting cycle, except for the initial stage of cold charge smelting: it can also operate at a constant rated power for the entire smelting cycle as needed. For large capacity and high power furnaces, it is recommended to configure a computer process monitoring system to ensure operational reliability at high melting rates. 5.2.11.4 Medium frequency power supply devices with a power greater than 500kW should generally be equipped with a rectifier transformer. The type of rectifier should be conducive to the reduction of grid harmonics. If necessary, a harmonic absorption device should be configured on the primary side (primary side) of the rectifier transformer. 5.3 Performance requirements
The performance of the medium frequency coreless furnace shall comply with the relevant provisions of 5.2 of GB/T10067.3--1988 and the following requirements. 5.3.1 Rated temperature
JB/T4280-2004
The rated temperature of the medium frequency coreless furnace is 1600℃ for melting steel; 1450℃ for melting iron; and the iron holding furnace is increased from 1350℃ to 1450℃ (i.e., the temperature is increased by 100℃). In actual operation, its rated temperature can be changed according to process requirements. 5.3.2 Unit power consumption, melting rate and heating rate The unit power consumption, melting rate and heating rate (applicable to holding furnace) of medium frequency coreless furnace shall be specified in the enterprise product standards. 5.3.3 Surface temperature rise
The surface temperature rise value of each component of medium frequency coreless furnace shall not exceed the provisions of Table 2. Table 2
Furnace frame, furnace shell, magnetic
Furnace bottom plate, furnace cover
Hydraulic system oil tank, large current busbar, etc.
Surface temperature rise
5.3.4 Noise
The noise of transformers, reactors, hydraulic devices, electrical switches, etc. used in medium frequency coreless furnaces shall be in accordance with the provisions of the corresponding standards. Under the rated operating state, the noise of the furnace body of the medium frequency coreless furnace shall not exceed 82dB. 5.4 Safety requirements
The safety requirements for the medium frequency coreless furnace shall comply with the relevant provisions in GB5959.3 and the following supplementary provisions. When there are additional requirements, they can be proposed in accordance with 9.2.
5.4.1 The length of the water inlet and outlet hoses used for all induction coils and water-cooled 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 operating normally, the electrical spacing and creepage distances between different charged bodies and between the charged bodies and the ground shall comply with the provisions of Table 3.
Zhongying main circuit voltage U.
Um≤500
500
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