JB/T 9207-1999 JB/T 9207-1999 Heat treatment of steel in endothermic atmosphere JB/T9207-1999 Standard download decompression password: www.bzxz.net

Mechanical Industry Standard of the People's Republic of China
JB/T9207-1999
Heat treatment of steeks in endothermic atmospheres
Heat treatment of steeks in endothermic atmospheresPublished on 1999-06-24
National Bureau of Machinery Industry
Implementation on 2000-01-01
3B9207—1999
This standard is a revision of ZRJ36012—8 Heat treatment of steeks in endothermic atmospheres: the relevant provisions have been edited and rectified, and the main technical contents have not been changed. This standard replaces 20J36012—89 from the date of implementation. This standard was proposed and approved by the National Technical Committee for Heat Treatment Standardization. This standard was drafted by the Fourth Design and Research Institute of the Ministry of Machinery Industry and Beijing Electromechanical Research Institute. The senior drafters of this standard are Wu Qiming, Yu Yanzhu, Zhang Deguang, Song Xiaohong and Xu Yue. This standard was first issued on March 29, 1989. Scope
Chinese Machinery Industry Standards
Heat treatment of steel parts in endothermic atmosphere
Heat treatment of steel parts in endothermic atmosphere eudothermicalnaspheresJB/T9207—1999
81:—89
This standard specifies the basic requirements for steel parts in endothermic nitrogen source gas, dust collectors, heat treatment furnaces, heat treatment processes, inspection and safety.
This standard is applicable to alkali-butane annealing, double annealing, light or net annealing, normalizing, nitrogen-carbon annealing and carbon annealing processes. 2. Referenced standards
The provisions contained in the following standards constitute unmarked provisions through reference in this standard. When this standard was published, the versions shown were all valid. All standards are subject to revision. Parties using this standard should explore the possibility of using the new versions of the following standards: GR.T 16—19RT
GR/T9152—1988
GBT 11354—1989
JB.T 2841—1993
JB.T 3999—1999
JBT 4155--1999
The following definitions are adopted in the blank standard.
3. Cavity aging
Architectural design fire code
Measurement method of effective heating zone of heat treatment furnace
Determination of ammonia layer depth of titanium steel parts Metallographic structure inspection Control gas generation device Basic technology Policy Steel instantaneous magnetic function Fire tempering
Gas nitrocarburizing process
When the furnace is used for the first time or after shutdown, the empty furnace is raised to a certain temperature (the temperature is lower than 760℃), and the carrier gas is introduced, and the magnetic potential of the gas inside is unstable.
4 Types and requirements of raw gas
4.1 Types
The raw gas commonly used for heat treatment is natural gas and liquefied petroleum gas. 4.2 Requirements
The raw gas or gas composition shall meet the requirements listed in Table 1, approved by the State Administration of Industry and Commerce on June 24, 1999, and implemented on January 0, 2000
Propane (or butane)
Alkanes above this range
Chemical spotsbZxz.net
Avoid high moisture
5 Heat treatment equipment
5.1 Endothermic atmosphere dust generation period
JB/T9207-1999
Natural gas
90% (volume)
50×10【】
5.1.1 The endothermic gas generator shall meet the relevant provisions of JB/T284I. 5.1.2 The gas composition and strength of the generator should be stable and meet the process requirements. 5.1.3 The gas composition of the generator should be controlled by dew point meter or CO, infrared meter and other instruments. 3.4 The generator can be heated by electric gas or liquid fuel according to the conditions. 2 The heat treatment furnace
Whether it is periodic or continuous, it should meet the following requirements. 5.2.1 Sealing
Lubei Shizhouer
(System》
【Volume】
(Volume】
450×10(volume
The heat treatment furnace should have good sealing performance, and all holes on the furnace body must be effectively sealed. When the ventilation plate is in place, the pressure in the furnace should be kept positive.
5.2.2 Insulation Accuracy
The maximum tolerance of the insulation accuracy of the effective heating zone of the heat treatment furnace should be +10%, and the temperature control indication accuracy should be within +4T. The measurement should be carried out in accordance with the provisions of GB/T452.
5.2.3 Furnace Gas Circulation
The gas and oxygen in the furnace should have reliable circulation, and a duct or air-guiding bag-shaped circulation loop can be used. The fan should have sufficient wind speed and air volume to ensure uniform distribution of the atmosphere in the furnace.
5.2. 4 Temperature control
Sufficient temperature control and over-temperature protection thermoelectrics are installed at appropriate locations in the effective heating zone to ensure accurate measurement and monitoring of the furnace temperature.
5.2.5 Carbon potential control
The carbon potential of the furnace atmosphere can be measured using a pyrolysis meter, CO, infrared meter, oxygen probe or other instruments. The carbon potential of the furnace atmosphere can be controlled or monitored using an automatic control device. Manual control can be used if the required carbon potential control degree can be achieved. 5.3 Cooling equipment
5.3.1 Cyclic or continuous The sealed furnace should adopt a sealed structure connected to the furnace. The cooling medium splash plate should be filled with an endothermic atmosphere or chlorine gas. 5.3. The smoke and steam generated by the cooling medium shall not enter the furnace. 2 JB/T9207—1995 5.3.3 The cooling medium should be equipped with a circulating device to ensure uniform cooling of the workpiece. 5.3.4 The temperature of the cooling medium should be controlled within the required range. If necessary, cooling and cooling devices should be configured. 5.4 Equipment inspection Equipment and instrumentation should be inspected regularly. Check and calibrate, and make a record. 6 Furnace atmosphere
6.1 Carrier gas
Use endothermic atmosphere as carrier gas
6.2 Ionizing gas
Use natural gas, alkanes or alkane as ionizing gas. The composition must be determined, and its requirements are the same as those of 4.2 Raw gas. 6.3 Additive gas
Additional gas is also required when acid and mouse are mixed. 6.4 Filtration and dripping
Carrier gas and ionizing gas should be mixed outside the furnace and then introduced into the furnace. The flow rate should be determined according to the furnace type, furnace volume, furnace pressure, magnetic field and workpiece surface area. Flow meters and regulating valves should be installed on the pipeline. 7 Heat treatment process
.1 Surface preparation
7.1.1 Before loading into the furnace, all workpieces, trays and clamps should be cleaned and moisture removed: 7.1.2 The workpiece surface should not have oxidation and decarburization layer (except for recarburization process) 7.2 Workpiece loading into the furnace
1 The workpiece must be placed in the effective heating area and reasonably supported to ensure uniform and smooth flow of gas cylinders. 2.2 Reduce the control process and load the same material and pre-heat-treated samples as needed. 7.3 Operation
7.3.1 When new oxidizer is used, it should be fully dried before reduction treatment. The oxidizer should be regularly replenished during use. 7.3.2 New furnaces and furnaces that are reopened after shutdown should be aged. 7.3.3 When the air conditioner and heat treatment furnace are used continuously, they should be burned regularly. 7.3.4 Before operation, check whether the thermoelectric alarm, furnace instruments and gas control instruments are operating normally. 7.7.5 Workpieces that do not directly produce fire after floating magnetism should be cooled in an endothermic atmosphere or under the protection of raw gas. Below the process sensing temperature, they should be cooled in full air.
8 Quality control and inspection
8. 1 Appearance
The surface of the workpiece is not allowed to have cracks, magnetism, rust and chemical scale: 8.2 Surface hardness and hardening depth
The carbon and carbon-nitrogen mixture should comply with the provisions of T399: The nitrogen-carbon mixture should comply with the provisions of JB/T4155 and GB/T11354. 8.3 The surface carbon content of the workpiece should be controlled according to the product requirements. The setting value is generally 10.8% 10: ℃ control structure is 8.4 The metallographic traces should meet the technical requirements of the workpiece or meet the requirements of the relevant standards. B.5. The deformation of the workpiece meets the technical requirements.
9. Records
Operation and inspection should include the following records: a) [number, name, material, teaching or event]; h) Equipment used;
e) Process parameters:
Temperature:
Time:
Gas nitrogen composition and salt used:
Oxygen carbon potential in the furnace;
Fire cooling medium and temperature,
Tempering temperature and time.
d) Inspection:
Depth of hardened layer:
Carbon monoxide:
Hardness (surface center;
Kumquat composition (surface center)
e) Inspection conclusion!
f) Processing date:
&) Operator and inspection signatures,
10 Safety
10.1 Safety facilities
, The layout of petroleum gas storage must comply with G16-1 Section 6 "Layout of petroleum gas storage tanks and fire protection spaces"
) There shall be no ignition sources, combustible materials and group buildings unrelated to the storage port in the safe separation area, especially underground emulsions, wind wells, etc.,
" Direct sunlight should be prevented, and spray cooling facilities should be provided. c) When storage chains are placed in groups, the distance between storage tanks should be at least one of the two largest storage tank diameters, and shall not be less than 1m. 10.1.2 Both the generator and the heat treatment furnace must be equipped with anti-slowdown devices, anti-vibration membranes or anti-exposure covers. 10.2 Safety Operation
JB9207-1999
[0.2.1 The generator and heat treatment furnace's drive, valves and joints are not allowed to leak and should be replaced regularly. [0.2.2 The heat treatment furnace exhaust pipe should be ignited and the car should be well ventilated. 10.2.3 When the temperature in the furnace is lower than 760°C, it is forbidden to use heating air. When the ventilation is lower than 700%, the air in the furnace must be exhausted in advance with an industrial rat
10.2.4 In the event of a fault or sudden power outage, the following emergency measures should be taken: 1) Connect the service power; or 2) Replace the gas in the furnace with a toxic gas (or 99.5% oxygen).
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