JB/T 9692.1-1999 Power frequency coreless induction melting iron (steel) furnace and iron holding furnace
Some standard content:
JB/T9692.1-1999
This standard is a revision of ZBK61002-90 "Power frequency coreless induction melting iron (steel) furnace and iron holding furnace". Compared with ZBK61002-90, this standard mainly deletes two reference standards JB/DQ5368.3-88 "Quality classification of electric heating equipment products Part 3 GW series power frequency coreless induction melting furnace" and JB/DQ5074 "Technology code for power frequency coreless inductors" that were abolished after review: the lining life index was deleted in technical content; the writing format is in accordance with GB/T1.1-1993, and the standard number, writing format and text of relevant contents are revised accordingly; the adoption degree of the referenced standards of the adopted standards is added; the English title of the definition is supplemented, etc. This standard is the first part of the series standard JB/T9692-1999. JB/T9692-1999 also includes the following parts: JB/T9692.2-1999 Power frequency coreless induction copper melting furnace JB/T9692.3-1999 Power frequency coreless induction aluminum melting furnace This standard replaces ZBK61002-90 from the date of implementation. This standard is proposed and managed by the National Technical Committee for Standardization of Industrial Electric Heating Equipment. The drafting units of this standard are Xi'an Electric Furnace Research Institute and Xi'an Heavy Electric Furnace Manufacturing Co., Ltd. The drafters of this standard are Wang Zifeng and Liu Xiping. This standard was first issued on April 6, 1990 and revised for the first time in 1999. The Secretariat of the National Technical Committee for Standardization of Industrial Electric Heating Equipment is responsible for the interpretation of this standard. 1'Scope
Machinery Industry Standard of the People's Republic of China
Mains frequency coreless, induction iron (steel) -melting furnace and iron-holding furnaceJB/T 9692.1 -1999
Replaces ZBK61002-90
This standard specifies the requirements for GW series power frequency coreless induction iron (steel) -melting furnace and GWB series power frequency coreless induction iron-holding furnace (hereinafter referred to as melting furnace and holding furnace or coreless furnace respectively), including variety specifications, technical performance, test methods, inspection rules, technical classification, ordering and supply, etc.
This standard applies to GW series melting furnaces with rated capacities of 0.75, 1, 1.5, 3, 5, 7, 10, 15, 20, 25, 30t and GWB series holding furnaces with rated capacities of 3, 5, 7, 10, 15, 20, 25, 30t. 2 Referenced standards
The provisions contained in the following standards constitute the provisions of this standard through reference in this standard. At the time of publication of the standard, the versions shown are valid. All standards will be revised, and parties using this standard should explore the possibility of using the latest versions of the following standards. GB/T10066.1-1988 Test methods for electric heating equipment General part GB/T10066.3—1988 Test methods for electric heating equipment Coreless induction furnace (eqvIEC60646:1992) GB/T10067.1—1988 Basic technical conditions for electric heating equipment General part GB/T10067.3—1988 Basic technical conditions for electric heating equipment Induction electric heating equipment GB5959.1—1986
GB5959.3—1988
GB50056—1993
GB 1094.2-—1996
JB/T 96911999
YB(T)14—1988
3 Definitions
This standard adopts the following definitions.
Safety of electric heating equipment Part 1 General part (eqvIEC60519--1:1984) Safety of electric heating equipment Part 3 Particular requirements for induction and conductive heating equipment and induction melting equipment (eqvIEC60519-3:1988) Design specification for electric heating equipment power installations
Power transformers Part 2 Temperature rise (eqvIEC60076-2:1993) Method for compiling product models of electric heating equipment
Casting pig iron
Except for the following supplementary provisions, the rest shall be in accordance with the provisions of Chapter 3 of GB/T10066.3-1988. 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 coreless furnace and marked on the nameplate. 3.2 Holding furnace
Approved by the State Bureau of Machinery Industry on August 6, 199960
Implemented on January 1, 2000
JB/T9692.1-1999
Refers to a coreless induction furnace used for holding or overheating molten metal to a specified temperature3.3 Heating-uprate
The ratio of the amount of charge to the time required for the liquid charge of a holding furnace to rise from the initial temperature to the final temperature. Note: In this standard, "heating-uprate" is used to replace 3.8 "heating productivity of the furnace" in GB/T10066.3-19883.4 Three-phase current unbalance factor refers to the quotient of the difference between the maximum and minimum values of the three-phase current on the secondary side of the transformer divided by the average value of the three-phase current, and is expressed as a percentage. 4 Product classification
Varieties and specifications
Centerless furnaces are divided into three varieties and multiple specifications according to their uses: iron melting furnace, steel melting furnace, and iron holding furnace. See Table 1 and Table 2 for details. Table 1 Main technical parameters of power frequency coreless induction iron (steel) melting furnace Variety code
Rated capacity
Main circuit rated power recommended range
270~320
320~360
450~520
750~800
1150~1350
1600~1800
2000~3000||t t||3000~4000
Melting cast iron
1450℃
Melt rate
kw·h/t
Melting cast steel
1600℃
Melt rate
Technical classification
Variety code
Variety code
4.2Model
Rated capacity
JB/T9692.1 -1999
Table 1 (end)
Melting cast iron
Recommended range of rated power of main circuit
3000~5000
4000~6000
5000~7500
Rated capacity
1450℃
Melt rate
kW·h/t
Melting cast steel
1600℃
Melt rate
Main technical parameters of industrial frequency coreless induction cast iron holding furnace Recommended value of main circuit rated power
Transformer capacity
kw·ht
-Technical classification
Tempering temperature 1350~1450℃
Tempering capacity
The model of coreless furnace should be compiled according to JB/T96911999, and the technical level code shall be determined according to 7.3 of this standard. 4.3 Main parameters
In the enterprise product standards, the following items should be listed separately for each model of coreless furnace:62
kw·h/t,s
a) power supply voltage, V;
b) number of power supply phases;
c) power supply frequency, Hz;
d) rated working voltage, V;
e) rated capacity, t;
f) rated power of main circuit, kW;
g) transformer capacity, kVA;
h) rated temperature, ℃;
JB/T 9692.1—1999
i) Melting rate (heating capacity), t/h (th; △=100℃);i) Power consumption, kw·h/t;
k) Cooling water pressure, MPa;
1) Cooling water consumption, m/h;
m) Furnace weight, t;
n) Overall dimensions, mm.
5 Technical requirements
5.1 General requirements
The coreless furnace shall comply with the relevant provisions of Chapter 5 of GB/T10067.3-1988. When the provisions of this standard differ from those of this standard, this standard shall prevail.
5.2 Supplementary requirements for design and manufacturing
5.2.1 Overall Design
The coreless furnace is mainly composed of furnace body, compensation capacitor bank, hydraulic or mechanical transmission device, cooling system and power supply, electrical control system, etc. Usually, one set of electrical equipment is equipped with one or two furnace bodies (one of which is spare). If the user does not need a spare furnace body, it can be proposed according to 9.2. The furnace body is generally a vertical tilting structure. The furnace chamber is a refractory crucible, and the furnace cover on the upper part of the furnace body can be opened and closed. The tilting part of the furnace body is installed on the fixed furnace frame and tilted by hydraulic or mechanical means. The coreless furnace is usually floor-standing or semi-underground. The design of the coreless furnace should focus on the overall assembly rigidity of the furnace body, the electrical performance of the coil, the leakage alarm, the water condition monitoring, etc. Its safety measures should be effective and reliable. The input power should be able to be adjusted according to the needs of each stage such as furnace baking, melting and insulation. The electrical control device, hydraulic system and water cooling system, especially the compensation capacitor bank, should be reasonably arranged as close to the furnace body as possible under the premise of ensuring safety and convenient maintenance. 5.2.2 Tilting furnace frame
The tilting furnace frame is a steel structure. The induction coil, yoke and furnace frame are connected as a whole. The furnace frame should be rigid enough to keep stable operation when tilting with the maximum charge. The furnace table panel should be tightly covered to prevent iron filings, sand and dust from falling into the induction coil. When there are special requirements, they can be proposed according to 9.2. 5.2.3 Fixed furnace frame
The fixed furnace frame should be able to support the weight of the furnace body (including the maximum charge) 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 9.2. 52.4 Furnace lining
JB/T 9692.1-1999
In addition to meeting the requirements of 5.1.4 in GB/T10067.3-1988, the thickness of the coreless furnace lining should meet the design size. The life of the furnace lining is related to the lining material, furnace construction process, the grade of the melted material, the furnace discharge temperature, the maintenance operation level, etc., and its recommended life value can be specified in the enterprise standard.
The baking and sintering process of the furnace lining should be specified in the enterprise product standard. 5.2.5 Insulation layer and heat insulation layer outside the crucible
There should be an insulation layer and a heat insulation layer between the furnace lining and the induction coil. The former should use insulation materials with H grade or above with reinforcement materials, and the latter should use insulation materials with a working temperature of not less than 500℃. 5.2.6 Induction coil
The induction coil shall comply with 5.1.3 and the following supplementary provisions in GB/T10067.3-1988. 5.2.6.1 The conductor of the induction coil shall be an eccentric copper tube or thick-walled copper tube of material not less than T, etc.; without complete inspection means, a single copper tube is not allowed to be extended and welded.
5.2.6.2After the induction coil is wound and formed, it should be insulated according to professional technology. The heat-resistant insulation grade of the insulation layer and insulating paint used should not be lower than Class H.
5.2.6.3The manufacturing dimensions of the induction coil should meet the design requirements, and the gap between the inner wall of the coil and the outer wall of the winding mold should not be greater than 0.2mm. 5.2.6.4The tap and lead of the induction coil should be firmly fastened, and the deviation of the lead and the parallel line of the radial center line of the coil should be within the range of ±5mm.
5.2.6.5Under normal use conditions, the service life of the induction coil (referring to insulation) for A, B, and C grade products should be not less than 7500, 11000, and 15000h respectively.
5.2.7Yoke
The yoke should be made of stacked silicon steel sheets. Its cross-sectional area and length should be able to limit the leakage flux and support the load of the induction coil, and it should be able to be fastened to the furnace body itself.
5.2.8 Furnace cover
The coreless furnace shall have a fixed or movable furnace cover, on which an observation hole may be provided. The movable furnace cover shall be opened and closed by manpower or other power. 5.2.9 Water cooling system
The water cooling system of the coreless furnace may be an open or closed 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 valve.
Except that the water resistance of the water cooling system shall meet the requirements of Table 3, the other requirements shall meet the requirements of 5.1.3.3 of GB/T10067.1-1988.
Table 3 Allowable water resistivity of water cooling system of coreless furnace Working voltage
>1000~2000
>2000~3000
5.2.10 Transmission system
Water resistivity n·cm
Coreless furnace generally adopts hydraulic transmission system, but mechanical transmission system can also be adopted for small capacity coreless furnace. The hydraulic system shall consist of oil pump and oil tank, etc. A mesh oil filter or magnetic oil filter shall be installed at the oil return point in the oil tank to filter out impurities and rust in the oil. An air filter shall be installed on the oil tank cover to prevent dust from entering the oil tank. The oil tank cover and the tank body shall be sealed. The hydraulic system is usually installed in the basement. For easy maintenance, the oil pump and main auxiliary devices shall be installed outside the oil tank. The pipelines of each part of the hydraulic system should be free of oil leakage to prevent accidents caused by accidental splashing of molten metal. The hydraulic system should make the opening and closing of the furnace cover and the tilting speed of the furnace body adjustable, stable, flexible and reliable. The maximum tilting angle of the furnace is 95° and is controlled by a limit switch. Appropriate protective measures should be taken to prevent sand and dust from the surrounding environment and molten iron from contaminating the working surface of the oil cylinder. 5.2.11 Power supply system
5.2.11.1 Unless otherwise required (see 9.2), the coreless furnace should be equipped with a power supply system of a voltage regulating device and a power switch device. The input power of the coreless furnace should be adjustable within a certain range to meet the different requirements of each stage of furnace drying, melting and insulation. The coreless furnace is allowed to be used for a long time when the deviation between the working voltage and the rated voltage is within +5%. In the enterprise product standards, additional instructions can be given if there are special provisions.
5.2.11.2 The coreless furnace should be equipped with a compensation capacitor and a balancing device to manually or automatically perform power factor compensation and three-phase balance adjustment. The three-phase current imbalance after the charge is melted should be no more than 12%, 10% and 8% for A, B and C grade products respectively. 5.2.11.3 The routing of the large current circuit of the coreless furnace should be arranged reasonably and the distance should be as short as possible. The gap between phases should comply with the relevant provisions of Table 10 in GB500561993.
The current density of the copper connecting busbar and copper cable of the large current circuit can be selected according to the cooling method in accordance with the following regulations: the self-cooling copper busbar is 1.5~2A per square millimeter, and the specific value can be determined according to the size and layout method; the water-cooled copper busbar and water-cooled copper cable should be no more than 3.5 and 10A per square millimeter respectively. If conditions permit, aluminum busbars can also be used to connect the busbars and cables. The selection of specifications and sizes should ensure that the heating temperature of the busbars and cables does not exceed the allowable value under the current load. When using parallel connection, the current distribution should be avoided as much as possible. 5.2.11.4 The capacitor shall have a special discharge device for automatic discharge through resistance or inductance after power failure. The device shall be able to make the maximum residual voltage of the capacitor lower than 50V after 60s of power failure. The capacitor shall have a fuse protection device. When an internal fuse is used, the external protection device can be omitted. 5.2.11.5 During operation (except for the impact of closing the switch), the power of the coreless furnace shall generally not exceed 110% of the rated power. When this limit is exceeded, it shall be operated at a reduced voltage.
5.2.12 Electrical control system
The coreless furnace shall have an electrical control system consisting of an electrical control cabinet (set), a contactor rack and an electrical operating table. The system shall be installed with various instruments as required before leaving the factory, and all internal connections shall be connected so that it can be put into operation as long as the external connections are connected on site. 5.2.12.1 The electrical control cabinet (set) is used to install various electrical instruments, components, etc. The control cabinet (set) shall have a signal display and button control system to indicate and control the actual working conditions. The electrical control of the coreless furnace shall meet the following requirements according to the technical level: Class A: Manual adjustment of power factor and three-phase balance; Class B: Automatic adjustment of power factor and three-phase balance. For coreless furnaces with a rated capacity of 10t and above, automatic weighing shall be adopted: Class C: Programmable microcomputer control shall be adopted, automatic display and recording, automatic adjustment of power factor and three-phase balance and automatic weighing shall be adopted. 5.2.12.2 Coreless furnaces above 1.5t shall have a lining leakage current monitoring device and a furnace leakage alarm device. Before the furnace leaks, an alarm signal shall be issued and the power supply shall be automatically cut off.
5.2.13 Capacitor rack
The capacitors on the capacitor rack shall be arranged neatly, and their spacing shall meet the installation requirements of the capacitors. The capacitor housing and capacitor rack shall be groundable and have obvious grounding marks. The material and cross-sectional area of the grounding conductor shall meet the requirements. 5.3 Performance requirements
The performance of the coreless furnace shall comply with the requirements of 5.2 and the following items in GB/T10067.3-1988. 5.3.1 Rated temperature
: The rated temperature of the steel melting furnace is 1600℃, the rated temperature of the iron melting furnace is 1450℃, and the iron holding furnace is increased from 1350℃ to 1450℃ (i.e., the temperature is increased by 100℃). In actual operation, its working temperature can be changed according to the process requirements. 5.3.2 Power consumption, melting rate or heating capacity
The power consumption and melting rate of the smelting furnace and its technical classification shall comply with the provisions of Table 1. The power consumption and heating capacity of the holding furnace shall comply with the provisions of Table 2, and no technical classification shall be made.
5.3.3 Surface temperature rise
The surface temperature rise of each part of the coreless furnace shall comply with the provisions of Table 4. :Table 4 Allowable surface temperature rise of coreless furnace
Furnace frame, furnace shell, magnetic yoke
Furnace bottom plate, furnace cover
Operating handle
Oil tank of hydraulic system, high current busbar, etc. 5.3.4 Overcharge
Allowable surface temperature rise<
When the coreless furnace uses a new lining, its maximum allowable overcharge is 10% of the rated capacity. In the later stage of lining wear, its allowable overcharge should not exceed 25% of the rated capacity.
5.3.5 Noise
The noise and technical classification of transformers, reactors, hydraulic devices, electrical switches, etc. used in the coreless furnace should be in accordance with the provisions of the corresponding standards. Under the rated operating state, the noise of the furnace body of the coreless furnace should not be greater than 82, 80, and 76dB for A, B, and C grade products respectively. 5.4 Safety requirements
The safety of 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 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 Necessary protective nets shall be installed at the easily accessible places of all power feeding parts of the coreless furnace. The furnace body, capacitor rack, contactor rack, electric control cabinet, transmission device, etc. shall be reliably grounded, and the grounding resistance value shall not be greater than 4Q. 5.4.3 In order to prevent accidents caused by sudden power outages and water outages, emergency power interfaces shall be reserved on the hydraulic device, and emergency water sources shall be available for water supply. 5.5 Requirements for complete sets
5.5.1 The scope of supply of coreless furnace complete sets specified by the supplier shall be listed in the enterprise product standards, which shall generally include the following items: a) furnace body;
b) hydraulic or mechanical transmission device;
c) operating table;
d) high-voltage switch cabinet or low-voltage switch panel;
e) electric furnace transformer
f) reactor;
g) capacitor bank;
h) contactor rack;
i) furnace change switch rack;
ji) control cabinet (table) and instrument;
k) water cooling system;
1)) water cooling cable;
m) temperature measuring instrument and compensation wire;
n) spare parts;
JB/T 9692.1-1999
0) Factory documents (including product manuals and necessary design drawings). For special-shaped non-standard bricks, an appropriate number of spare parts should be provided. In the enterprise product standards, the specific contents of the above items should be listed, including models, specifications and quantities. If the purchaser has different requirements for the items specified by the supplier, it can be proposed in accordance with 9.2. 5.5.2 When the following accessories or devices are required to be provided, they can be proposed in accordance with 9.2, and their technical conditions shall be agreed upon by the supply and demand parties. a) Power factor and three-phase balance automatic control system; b) Electronic automatic weighing device and accessories;
c) Emergency device;
d) Furnace building and dismantling tools;
e) Cooling device and accessories;
f) Smoke exhaust and dust removal device.
6 Test method
The test method of the coreless furnace shall be carried out in accordance with the relevant provisions of GB/T10066.1 and GB/T10066.3 and the following supplementary provisions. 6.1 The measurement test of the power consumption, melting rate or heating capacity of the main circuit of the furnace shall be carried out in accordance with 5.8 and the following supplementary provisions of GB/T10066.3-1988. a) The test shall be carried out in the hot furnace state after three consecutive smelting furnaces; b) The remaining amount of liquid charge in the furnace is stipulated to be one-half of its rated charge; c) The test charge shall be ordinary cast pig iron in accordance with the provisions of YB (T) 14--1988 for iron melting furnaces; ordinary medium carbon steel shall be used for steel melting furnaces.
Each test charge should weigh 5~7kg, and the length should not exceed 200mm. The surface should be free of slag, sand, rust or oil stains; d) The number of times of charging during the test shall not exceed 3 times for coreless furnaces below 10t; and not more than 5 times for coreless furnaces of 10t and above. The number and time of opening the furnace cover should be minimized during the test. 6.2 Measurement of charge temperature
The measurement of charge temperature shall be carried out in accordance with 5.11 of GB/T10066.3-1988, but the thermocouple shall be inserted 200mm below the liquid surface. 6.3 No-load test
Electrify the empty furnace (without putting in crucible mold and charge), check whether there are abnormal phenomena in the vibration of the electric furnace, insulation between coil turns, heating at the line connection, electrical switching and adjustment accuracy, instrument operation, etc. The test should start from low voltage and step by step increase the voltage until it runs continuously for more than 30 minutes at the rated voltage. The temperature rise of the furnace shell is not checked. 6.4 Measurement of surface temperature rise
The measurement points of surface temperature rise are as follows:
a) Any point on the outer surface of the furnace frame, furnace shell, yoke, furnace bottom plate, furnace cover and operating handle; b) The outer surface of the oil tank of the hydraulic system;
c) Any point on the outer surface of the large current bus, water-cooled cable terminal and capacitor. The electrode lead-out hole at the bottom of the furnace, the outer surface of the furnace shell and the furnace cover near the furnace mouth, the part within 100mm from the edge of the observation hole, and the part of the yoke end buried in the refractory material are not within the measurement range. Use a surface thermometer with a measurement accuracy of not less than 2.5 for measurement, and do not use a glass thermometer. 6.5 Measurement of oil temperature of transformers and reactors
The test shall be carried out in accordance with the provisions of GB1094.2-1996. 6.6 Inspection of leakage alarm device
During the factory test, input analog signals to observe whether the alarm device operates normally; during the type test, after the metal is melted, measure the voltage and current changes of the furnace lining. It can be carried out in accordance with the provisions of the enterprise product standards. 6.7 Measurement of three-phase current imbalance
Under normal operation, adjust the compensation capacitor to make cos→1, and adjust the balance capacitor to make the three-phase current values have the smallest difference, then the percentage of imbalance is:
= lx m ×100%
Where: Imax
—maximum current among three-phase currents, A;
Imin—minimum current among three-phase currents, A; I—average current of three phases, A.
6.8 Power supply and electrical control system test
The test method shall be specified in the enterprise product standard. 7 Inspection rules and classification
The inspection and classification of coreless furnaces shall be carried out in accordance with Chapter 7 of GB/T10067.1-1988 and Chapter 7 and the following articles of GB/T10067.3-1988.
The factory inspection items of coreless furnace are as follows: a) general inspection;
b) safety inspection;
c) durability test of label writing;
d) inspection of furnace body assembly dimensions;
e) inspection of induction coil manufacturing quality;
f) measurement of electrical clearance between induction coil and furnace shell; g) measurement of insulation resistance of induction coil to furnace shell; h) insulation withstand voltage test of induction coil;
i) calibration of electrical instruments;
JB/T 9692.1-1999
j) Power-on test of the operation of each component of the electrical system; k) Cold test of the operation or operation of the motion mechanism: 1) Inspection of the electrical interlock and furnace leakage alarm device; m) Inspection of the water system and hydraulic system; n) Inspection of supporting parts, including inspection of model, specification, and factory qualification certificate; o) Scope of supply, including inspection of the completeness of factory technical documents; P) Packaging inspection.
7.2 The type inspection items of coreless furnace are stipulated as follows: a) All factory inspection items (under type inspection conditions): b) Power supply and electrical control system test; c) No-load test; d) Measurement of rated power and power factor of main circuit; e) Measurement of furnace power and power factor; f) Measurement of charge temperature; g) Measurement of insulation power of furnace main circuit; h) Measurement of power consumption, melting rate or heating capacity of furnace main circuit; i) Measurement of surface temperature rise; j) Measurement of transformer and reactor oil temperature; k) Inspection of water system; 1) Inspection of leakage alarm device; m) Measurement of three-phase current imbalance: n) Measurement of noise; 0) Inspection after hot test. 7.3 The technical classification of coreless furnace shall be in accordance with Table 5. Centerless furnaces of all technical levels should fully meet the requirements listed in the table and other provisions of this standard.
Table 5 Technical classification of coreless furnace
Technical level
Induction coil
Three-phase current imbalance
Electrical control
Power consumption, melting rate or heating capacity
According to the requirements of 5.2.6.5
According to the requirements of 5.2.11.2
According to the requirements of 5.2.12.1
According to the requirements of 5.3.2
According to the requirements of 5.3.5
Can be provided according to the requirements of 5.5.1
Can be provided according to the requirements of 5.5.1 and 5.5.2 except f
Can be provided according to the requirements of 5.5www.bzxz.net
7.4 National-grade coreless furnaces meet the requirements of the above C-level in terms of technology. 69
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