JB/T 4311.5-2002 Indirect resistance furnace RJ series natural convection pit resistance furnace
Some standard content:
ICS25.180.10
Chinese Mechanical Industry Standard JB/T4311.5—2002
Replaces JB/T4311.5—1991
Indirect resistance furnaces-RJ series natural convection pit type resistancefurnace
2002-07-16issued
2002-12-01implemented
issued by the State Economic and Trade Commission of the People's Republic of ChinaForeword,
1Scope,
2Normative references
3Terms and definitions
4Product classification
4.1Varieties and specifications
4.3Main parameters..
5Technical requirements..
5.1General requirements
5.2Supplement to design and manufacture Requirements
Performance requirements
5.4 Complete set requirements,
6 Test methods.
6.1 Measurement of furnace temperature uniformity and furnace temperature stability Measurement of surface temperature rise
Heating capacity test
6.4 Charging operation test
7 Inspection rules and grade classification
8 Marking, packaging, transportation and storage
9 Ordering and supply.
Appendix A (informative appendix) Working area dimensions and furnace dimensions of some specifications of pit-type furnaces, Appendix B (informative appendix) Empty furnace energy consumption of some specifications of pit-type furnaces. JB/T4311.5—2002
JB/T4311.5--2002
The complete set of industry standards for "Indirect Resistance Furnace" currently has the following 13 parts: -RX series box-type resistance furnace (JB/T8195.1): -RM series box-type itching furnace (JB/T8195.2): ZR series vacuum heat treatment and brazing furnace (JB/T8195.3): ZC series vacuum furnace (JB/T8195.4); RT series trolley resistance furnace (JB/T4311.3): R J series natural convection pit resistance furnace (JB/T4311.5): SX series experimental box resistance furnace (JB/T4311.7): SK series experimental tube resistance furnace (JB/T4311.8): SG series experimental crucible resistance furnace (JB/T4311.10); RF series forced convection parallel resistance furnace (JBT5264): RB series bell-type resistance furnace (JB/T5265): RY series electric heating bath furnace (JB/T5266): RCW series mesh belt resistance furnace (JB/T6206). This part replaces JB/T4311.51991 "Indirect resistance furnace RJ series natural convection pit resistance furnace". Compared with JB/T4311.5-1991, the main changes of this part are as follows: the types are changed from 1000℃ and 1200℃ to 950℃, 1200℃ and 1350℃ (see 4.1.1); the height requirements in the working area size (diameter × height) are changed (see 4.1.2); the original classification regulations for the overhaul period of the furnace lining and the service life of the heating elements are cancelled, but the minimum requirements are retained (see 5.2.4 and 5.2.5); in view of the newly added 1350℃ type, the material of the heating element and the voltage regulating device are changed. Supplementary provisions have been made (see 5.2.5): The lower limit of the working temperature of a pair of pit furnaces has been changed from the original unified regulation of 750℃ to be agreed upon by the manufacturer and the user (see 5.3.1): The furnace temperature uniformity has been differentiated and adjusted according to different varieties (see 5.3.4 and Table 2): Due to the change in the size of the working area, the furnace size (Appendix A), empty furnace loss (Table 6 of the 1991 edition, Table 5 of this edition) and empty furnace energy consumption (Appendix B) of some specifications of pit furnaces have been modified, and the index values of empty furnace loss and empty furnace energy consumption have been appropriately reduced. Appendices A and B of this part are informative appendices. This part was proposed by the China Machinery Industry Federation. This part is under the jurisdiction of the National Technical Committee for Standardization of Industrial Electric Heating Equipment (CSBTS/TC121). Drafting units of this part: Xi'an Electric Furnace Research Institute, Jiangxi Electric Furnace Factory. The main drafters of this part: Ge Huashan, Liu Fubao The previous versions of the standards replaced by this part are: JB2706-1980, JB4311.5-1987, JB/T4311.5-1991. 1 Scope
Indirect resistance furnace
RJ series natural convection pit resistance furnace
JB/T4311.5-2002
This part specifies the requirements for RJ series natural convection pit resistance furnace products (hereinafter referred to as pit furnaces), including varieties, specifications, technical performance, ordering and supply, etc.
This part is applicable to natural convection pit resistance furnaces with a maximum working temperature of 950℃, 1200℃ and 1350℃, which are mainly used for rate heating, annealing, normalizing, etc. of steel parts in natural atmosphere or protective atmosphere. This part is also applicable to similar natural convection pit resistance furnaces, and different parts may be specified separately. 2 Normative references
The clauses in the following documents become the clauses of this part through reference in this part of JB/T4311. For all referenced documents with dates, all subsequent amendments (excluding errata) or revisions are not applicable to this part. However, parties that reach an agreement based on this part 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 part. GB/T10066.1-1988 Test methods for electric heating equipment General part (eqvIEC398:1972) GB/T10066.4-1988 Test methods for electric heating equipment Indirect resistance furnace GB/T10067.1-1988 Basic technical conditions for electric heating equipment General part GB/T10067.4-1988 Basic technical conditions for electric heating equipment Indirect resistance furnace JB/T3649.6 Refractory products for resistance furnaces Anti-carburization refractory products JB/T9691-1999 Method for compiling product models for electric heating equipment 3 Terms and definitions
The terms and definitions established in Chapter 3 of GB/T10066.4-1988 and the following terms and definitions apply to this part of JB/T4311. 3.1
Furnace hearth dimensions of furnace membrane space specified by design, usually expressed in diameter and height. For pit-type furnaces with a furnace opening diameter smaller than the internal clearance diameter of the furnace, the "diameter" in the furnace size is the furnace opening diameter, and the "height" is the clearance distance between the top bricks and the furnace bottom in the furnace: the rest is specified by the enterprise product standard.
Note 1: The furnace dimensions in Appendix A are the nominal dimensions of the furnace cavity, which are the case where the furnace opening diameter is smaller than the internal clearance diameter of the furnace. Note 2: The furnace dimensions referred to in 7.1d) shall be defined in accordance with the provisions of the enterprise product standard. 3.2
Protective atmosphereprotectiveatmosphereThe atmosphere used to protect the charge in the pit-type furnace to avoid or reduce oxidation and decarburization. 4 Product classification
4.1 Varieties and specifications
4.1.1 Parallel furnaces are divided into multiple varieties according to the atmosphere and maximum operating temperature, see Table 1. Other maximum operating temperature values are allowed in the enterprise product standards. In this case, the number of the variety code (maximum operating temperature divided by 100, minus the decimal) should be changed accordingly.
JB/T4311.5-2002
Product code
Natural atmosphere
Protective atmosphere
4.1.2 Each type of pit furnace is divided into multiple specifications according to the size of the working area. Maximum working temperature
Unless otherwise agreed by the supply and demand parties, the working area size (diameter DX height H) of the pit furnace shall comply with the following regulations. The minimum diameter D is 500mm, and the rest increase by 200mm. The minimum height corresponding to each diameter D is the diameter D plus 50mm, and the rest increase by 400mm. For example: if D is 900mm, the value of H can be: 950mm, 1350mm, 1750mm, 2150mm, 2550mm, etc. The position of the working area in the furnace barrier should be indicated on the attached drawing in the pit furnace product manual. 4.1.3 Each pit furnace manufacturer can choose from the varieties and specifications specified in 4.1.1 and 4.1.2, and formulate their own parallel furnace enterprise product standards accordingly.
4.2 Model
The model of the parallel furnace should be compiled in accordance with JB/T9691-1999, and the technical level code shall be determined in accordance with 7.4. 4.3 Main parameters
In the enterprise product standards, the following items should be listed separately for each model of parallel furnace: a)
Power supply voltage, in V;
Power supply frequency, in Hz;
Number of phases;
Rated power, in kW;
Number of temperature control zones;
Connection method of heating elements:
Working temperature, in °C;
Working zone size, in mm;
Maximum loading capacity, in kg;
Heating capacity, in k g/h;
Empty furnace heating time, unit is h:
Furnace temperature uniformity, unit is ℃;
Furnace temperature stability, unit is ℃:
Empty furnace loss, unit is kW:
Surface temperature rise, unit is K;
Empty furnace energy consumption, unit is kW·h:
Applicable atmosphere and gas (or liquid) consumption, unit is m2/h (under standard conditions) (or kg/h) (for RJQ type pit furnace):Furnace body weight, unit is t:
Furnace body dimensions, unit is mm.
5 Technical requirements
General requirements
Parallel furnaces shall comply with the provisions of Chapter 5 of GB/T10067.4-1988. In case of any discrepancy between the provisions of this standard and this part, this part shall prevail. 5.2 Supplementary requirements for design and manufacture
5.2.1 Overall design
JB/T4311.5-2002
The pit-type furnace is mainly composed of the furnace body and the control cabinet. The furnace body is a vertical cylindrical or other vertical polyhedral shape with an open top, which is used to load and unload the charge vertically from above. There is a furnace cover on the furnace mouth. The design of the furnace body should take into account the convenience of loading and unloading the charge with lifting equipment. When it is required to be equipped with a device for hanging the charge inside and outside the furnace, it can be proposed according to 9.2. For furnaces with a working area height greater than 3 times the diameter, when necessary, one or more rapid cooling holes can be opened at appropriate positions at the bottom of the furnace. These holes should be able to be closed at ordinary times. When it is necessary to accelerate the cooling of the furnace, they should be able to be opened or connected to the ventilation device, or a structure with a detachable furnace bottom can be used. When required (see 9.2), RJQ type pit-type furnaces should be equipped with a cooling device with a heat exchanger to circulate and cool the furnace gas.
RJQ type pit furnaces shall have inlet pipes for protective gas and necessary valves, etc., or devices for generating protective gas by cracking in the furnace, so that the charge can be heated in the required atmosphere (see 9.1). Pit furnaces are generally not equipped with furnace pots.
5.2.2 Furnace shell
The furnace shell is a round shell or other polyhedron shape, welded with steel plates of appropriate thickness, and reinforced with steel sections when necessary. The entire furnace shell shall have sufficient strength, rigidity and stability to ensure its long-term reliable operation. The furnace roof shall be made of steel materials that are not easy to deform, warp, crack, and have sufficient thickness. The furnace shell of RJQ type non-furnace pot furnace shall be welded into an airtight whole. 5.2.3 Furnace cover
The furnace cover shall be lined with high-quality refractory insulation materials. Refractory fibers shall be preferred, and lightweight bricks may also be used. The performance and thickness of the refractory insulation materials shall ensure that the surface temperature rise of the furnace cover does not exceed the provisions of 5.3.6. There should be a reliable seal between the furnace cover and the furnace top surface to minimize air leakage. The structure of the furnace cover can be integral lifting type, integral horizontal swing type, integral horizontal removable type, split upward swing type, split horizontal removable type, etc., which can be determined according to the size of the furnace and the use requirements. The furnace cover can be operated manually or driven by power. When operated manually, the force required to lift, swing or close the furnace cover should not exceed 180N. When the purchaser has other requirements for the structure and drive mode of the furnace cover, it can be proposed according to 9.2. 5.2.4 Furnace Village
The material and structure of the furnace lining should meet the performance requirements for pit furnaces (see 5.3). The lining of the C-level pit furnace of RJ10, RJ12 and RJ13 should be made of refractory fibers except for the load-bearing and collision-prone parts. The lining in contact with the carbon-containing atmosphere should be made of lining materials suitable for the atmosphere, such as anti-carburization refractory products that meet the requirements of JB/T3649.6.
The overhaul period of the furnace lining shall not be less than 4 years for the brick lining and not less than 2 years for the refractory fiber lining. 5.2.5 Heating elements
For pit-type furnaces with a maximum operating temperature not exceeding 1200°C, the heating elements shall be made of electric heating alloys; for those above 1200°C, silicon carbide or materials with the same or better comprehensive properties shall be used. When selecting the heating element materials for RJQ pit-type furnaces, the effect of the atmosphere on the materials shall be considered. For furnaces using non-metallic heating elements such as silicon carbide, multi-tap transformers or other voltage regulating devices shall be equipped. The service life of metal heating elements shall not be less than 5000h, limited to the input power of the pit-type furnace at the rated power supply voltage being 15% less than the rated power. The service life of non-metallic heating elements shall be specified by the enterprise product standards. 5.2.6 Measurement, control and recording
The measurement, control and recording of parallel furnaces shall comply with 5.2.7 of GB/T10067.4-1988 and the following supplementary provisions. The control type of the temperature control instrument of the pit furnace should generally be a time proportion type that controls the contactor through an intermediate relay system, or other technically more advanced types. For Class A pit furnaces, the position control type can be retained. For Class C pit furnaces, a microprocessor digital display temperature control instrument with a temperature setting accuracy of not less than 0.5% and a resolution of not less than 1°C should be equipped. The digital height should not be less than 15mm. The instrument should be equipped with an external socket to connect a recorder or printer. The effective width or diameter of the temperature recorder recording paper should not be less than 150mm. When a printer is required to replace the recorder, it can be requested according to 9.2.
5.3 Performance requirements
The performance of the pit furnace shall comply with 5.3 and the following requirements of GB/T10067.41988, JB/T4311.52002
5.3.1 Working temperature
The working temperature range of each type of pit furnace shall be agreed upon by the manufacturer and the user, and the maximum working temperature is shown in Table 1. Within the working temperature range, the temperature uniformity and temperature stability of the parallel furnace shall meet the requirements of 5.3.4 and 5.3.5. 5.3.2 Maximum loading capacity
Unless otherwise required (see 9.2), the maximum loading capacity of the pit furnace shall be specified in the enterprise product standards according to the following requirements. 5.3.2.1 For all pit furnaces that bear the load from the bottom of the furnace, as well as externally suspended pit furnaces with a maximum working temperature not exceeding 950°C and a working area height not exceeding 4m, and with a maximum working temperature exceeding 950°C but not exceeding 1200°C and a working area height not exceeding 2m, the maximum loading capacity, measured by the weight of steel workpieces, shall not be less than 2500×V, in kg, where V is the working area volume, in m. 5.3.2.2 The maximum loading capacity of other types and specifications of parallel furnaces shall be separately specified in the enterprise product standards, or agreed upon by the supply and demand parties (see 9.2).
5.3.3 Heating capacity
5.3.3.1 Unless otherwise required (see 9.2), the heating capacity of the pit furnace shall be specified in the enterprise product standards in accordance with the following requirements. 5.3.3.2 For pit-type furnaces with a maximum operating temperature not exceeding 950°C and a working area height not exceeding 4m, and a maximum operating temperature exceeding 950°C but not exceeding 1200°C and a working area height not exceeding 2m, the heating capacity, measured by the weight of steel heated in 1h, shall not be less than 300×D×H, in kg, where D and H are in m. The test temperature for assessing the heating capacity is the maximum operating temperature. Note: The heating capacity is generally between (300 and 500)×DXH, in kg/h. For small furnaces, the larger value shall be taken.
5.3.3.3 The heating capacity of other types and specifications of pit-type furnaces shall be separately specified in the enterprise product standards, or agreed upon by the supply and demand parties (see 9.2).
5.3.4 Furnace temperature uniformity
The furnace temperature uniformity of a pit-type furnace shall not exceed the range specified in Table 2Table 2
Product code
RJ(Q)9,RJ(Q)12
RJ(Q)13
5.3.5 Furnace temperature stability
The furnace temperature stability of a parallel furnace shall not exceed the following specified range: Class A furnace: ±10℃;
Class B furnace: ±4℃;
Class C furnace: ±1℃.
5.3.6 Surface temperature rise
Furnace temperature uniformity℃
When a parallel furnace is in a thermally stable state at the highest operating temperature, the surface temperature rise of its furnace shell, furnace cover and furnace roof shall not exceed the range specified in Table 3. The surface temperature rise of the operating handle or handwheel shall not exceed 25K. 3
Maximum working temperature℃bzxz.net
Location and furnace cover structure type
Furnace cover and furnace top plate
Furnace cover and furnace top plate
Integral furnace cover
Half furnace cover
Integral furnace cover
Half furnace cover
Surface temperature riseK
5.3.7 Empty furnace heating time
JB/T4311.5—2002
Unless otherwise required (see 9.2), the empty furnace heating time of a pit furnace with a working area volume not exceeding 2.5m shall not exceed the requirements of Table 4. Table 4
Working area volume Vm
0.3
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