Some standard content:
IC'S21.200
Machinery Industry Standard of the People's Republic of China
IB/T9173-1999
Gear carbonitriding process and its quality control
Issued on 1999-06-24
National Bureau of Machinery Industry
Implemented on 2000-01-01
.FB/T 9173—1999
This standard is a revision of ZBJ1?002—88 Gear carbonitriding process and its quality control. This standard replaces ZBJ17002—88 from the date of implementation. This standard was proposed and approved by the National Gear Standardization Technical Committee. The responsible person for drafting this standard is the China Machinery Research Institute. The main drafters of this standard are Wu Ziyi, Wang Ling, Chen Qian, Zhang Jianhua and Yang Caoyuan. Scope
Machinery Industry Standard of the People's Republic of China
Car carbanitriuing prucess and its quality control for gears
Gcar carbanitriuing prucess and its quality control This standard specifies the material selection, management equipment, process and quality control of carbanitriuing gears. This standard specifies the gas carbanitriuing prucess and its quality control for gears made of tungsten steel. 2 Referenced Standards
JE.T 9173-19W
With reference to J17002-88
The provisions contained in the following standards constitute the provisions of this standard by reference in this standard. When this standard is published, all versions are valid. All standards will be revised. Parties using this standard should explore the possibility of using the latest version of the following standards: GB/T230..J991
B/T 6991988
Method for testing age of alloy Rockwell hardness
Technical conditions for high-quality carbon steel
GB/TS077--19RR
Technical conditions for alloy steel
GR/T8539-1997
GR/T 94501988
JIG 741992
3 Terminology
General provisions for quality inspection of gear materials and heat treatment Determination and calibration of carbon content of steel parts Verification procedures for automatic balancing display instruments
This standard uses the following terms:wwW.bzxz.Net
3.1 Internal oxidation black structure
On the surface of the hydrocarbon coating layer, due to the internal oxidation and molecular effects of hydrogen and carbonitride polymerization, the black structure defects can be detected without etching.
3.2 Non-corrosive black structure
The non-martensitic network structure formed by the decrease in the permeability of the layer caused by the internal oxidation and carbonitride polymerization.
3.3 Core iron body
refers to the iron body near the intersection of the center line of the gear and the tooth root on the normal section of the middle of the gear after being annealed and annealed.
3.4 Surface hardness drop
The difference between the Vickers hardness value on the annealing layer and the surface Vickers hardness value within the depth of the effective hardened layer of carbon fiber. 3.5 Hardness reduction of the whole core
In the typical application of carbon-nitrogen co-hardening, the hardness gradient of the tooth surface towards the core on the cross section of the co-layer is V3FHI,
Approved by the State Machinery Industry Bureau on 1999-16-24 and implemented on 2000-01-01
4 Material selection
JB/T9173-1999
4.1 Commonly used materials for carbon-nitrogen co-hardening gears: 20CrMo, GMo35CrMo, 20CrMnTi, 30CrMnTi, 8CrS, 20CrMnMe20CrMiMoA: 20Cr2Yi4A, etc.:
12 The quality of the steel plate meets the requirements of GR/T377 and G69. Gears with high precision requirements should be made of high-quality steel, high-quality steel and air degassing, and non-metallic materials and belt groups with force inspection can be required! 4.3 For high-precision gears, materials with high modulus should be selected, and the depth of the co-infiltration layer should be required to be correspondingly thin: 4.4 Heavy-duty gears should be made of 20CrMoA, 20Cr2N4A and other materials: 5 Equipment requirements
5.1 Use a velvet-type or box-type controlled atmosphere furnace to introduce gas hydrogen co-immersion, and the temperature in the effective heating zone should be controlled to a predetermined value = 5
5.2 It is allowed to use a well-type full-injection carbon co-immersion, and effectively add The temperature inside the furnace should be controlled at a constant value of 1095.3 The substation and gas source pipeline system must have good performance to ensure that the atmosphere meets the environmental protection requirements during the production process. The furnace gas circulation equipment should be installed to ensure the uniformity of the gas layer. 5.4 Each heating zone of the nitriding furnace should be equipped with a recording device that can automatically measure and track the actual temperature. The accuracy of the measuring instrument should be ≤ 0.5 grade (JG74-1 double). 5.5 The frequency control of the gas in the furnace should be carried out with appropriate instruments to ensure that the carbon potential and the viscosity meet the specified viscosity requirements. 5.6 All carbon coagulation plates: The main ears are recommended to be made of heat-resistant steel or heat-resistant castings, and no obvious deformation is allowed during use. 5.7 The cooling plate should be equipped with heat and circulation cooling devices. The temperature of the cooling medium should be able to rise quickly during use: the preset temperature is ± 25 °C
38. The gears should not be affected by oxidation, corrosion, and other harmful effects, and the performance should meet the relevant technical requirements. The optimal ignition medium is No. 20, No. engine oil, cylinder oil or other special ignition medium; its cooling performance should be checked regularly, and impurities should be removed regularly. 6 Process control
6. Carbonitriding agent
61.1 Carbonating agent: It is recommended to use ethyl aldehyde, monomethyl ether, methane, alkane, butane, etc., and small saturated hydrocarbons and low sulfur content bacteria oil can be used. 6.1.2 Nitrogen supply agent: It is recommended to use ammonia, and formamide, or nitrogen, triethanolamine and other nitrogen supply agents can also be used. 1.3 The purity of the nitrogen supply agent should reach the lowest industrial purity level. 6.1.4 The filter shall not have a harmful effect on the gear gauge and separation process, and shall comply with the respective standards or technical conditions: 6.2 Pre-treatment acceptance and preparation
6.2.1 The technical requirements for heat treatment shall be understood in detail, 6.2.2 The quality of steel materials, plating, pre-heat treatment and machine inspection shall meet the technical requirements, 6.2.3 Formulate technical specifications, determine the use of equipment, furnace loading method and furnace loading quantity. 6.2.4 The surface of the gear shall be free of rust, live, corrosion, aging, etc., and shall be numbered, registered and loaded. 6.1.5 The mounting method of the gear shall be selected appropriately. For thin-walled gears with a certain modulus, it is recommended to use the hanging method: 6.3 Furnace loading
The quality of the samples inspected with the furnace shall be consistent with the heat treatment conditions and the same gears as those tested, and the quantity shall be kept in the same space as the gear.
6.4T Technical Standard
JB/T 9173—1999
6.4.1 For carbonitride composite gears with a depth of less than FU.5mm, the composite temperature is generally 800-840T, and the average temperature can be calculated around 0.12mm.
6.4.2 When the penetration depth is 0.5-6.8mm, the temperature is generally 840-880, and its average growth rate can be as high as 0.15mm. For gears with high estimation accuracy requirements, it should be pre-cooled to a lower temperature (higher than 4r) in the furnace after medium temperature, and processed isothermally, and then released from the fire.
6.4.3 The penetration depth is required to be greater than 0.8mm. It is recommended to adopt a two-stage method. The first stage uses 880-920 for high-altitude carbon-nitrogen welding, and then cools down to 820-80 for medium-temperature carbon-nitrogen welding. The average temperature can be as low as 0.18mn. 6.4.4 Filtration time: It should be determined based on the skin depth requirements and the actual measured results of the expanded sample. 6.4.5 For the parts of the product that need to be impermeable, anti-explosive materials or other anti-poisoning measures can be used, and the pressure of the plated furnace should be controlled as much as possible to prevent the leakage of hydrogen. 6.4.6 For the total time, the pressure of the through-type 2 furnace is 40~2Pa, and the pressure of the surrounding furnace is controlled at 150~509Pa: 6.4, for the endothermic controlled atmosphere, the amount of the gas is 2%~3.5% (the total amount of gas). When using the drip-type nitrogen filter, the batch flow is 25%-35% (the total amount of gas is estimated by the sum of the gasification and hydrogen flow). 6.4.8 When using the full-injection carbon atmosphere filter, it is recommended to use methanol, ethanol or nitrogen for exhaust. Do not pass hydrogen or other methods at the beginning of the process. Use it for exhaust. 4.9 When the chrome chain titanium steel gear is carbon-nitrogen co-exhausted, in order to avoid the generation of color defects, the ammonia supply is biased., and adopt the late nitriding to shorten the nitriding time.
T Quality Control and Inspection Methods
7.1 Appearance: After the gear is carbonized and painted, the surface shall be inspected by the limit, and there shall be no defects such as oxidation, dents, peeling, rust, etc. 7.2 The average carbon concentration of the first surface layer of the carbonitriding layer from the surface to the depth of 0.1mm shall be controlled at 0.75%~0.95%, and the average nitrogen content shall be controlled at 0.15%-0.30%, and the layer analysis method shall be used for inspection. 7.3 The carbonitrided layer shall be evenly distributed in granular or small-sized shapes, and shall not be distributed in a cluster or continuous network. It shall be inspected by metallographic analysis.
7.4 The martensitic layer shall be needle-shaped, and the needle length is allowed to be greater than 0.02mm. Use metallographic method to check the surface of the middle part. 7.5 The residual bismuth of the eutectic layer should be 1.5%-30%, and it is not allowed to be higher than 40%. Use metallographic method to check the surface of the middle part of the tooth. Note: When using the machine method to check the bismuth number of the product, the sample is fully calcined and maintained. It is necessary to use the Vickers design or this method.
7.6 The eutectic layer black negative paper defects are divided into two types: internal hydrogenation type and mineral type. Use metallographic method to check near the root: 7.6.1 Internal oxidation type black fabric is not checked by corrosion, and no accumulation is allowed. The depth of the point and black network shall not be less than n.13mm. 7.6.2 Oil mineral type needs to be checked after corrosion, and the width of the black network shall not be less than 0.04mm. 7.7 For carbonitriding gears with a modulus of 3.5mm, the core iron content should be controlled at no more than 4%; for tungsten gears with a modulus of 1.5~5m, the core iron content should be controlled at no more than 8%. Use the gold method to control the intersection of the center line of the wheel and the tooth root. 7.8 The depth requirements of the effective hardening layer of carbonitriding shall be in accordance with the product drawings. 7.8.1 The depth of the effective hardening layer of carbonitriding shall be controlled at a lower level, and generally it shall be allowed to be 10%~20% thinner than the depth of the effective hardening layer of carbonitriding. 7.8.2 The depth of the effective hardening layer of carbonitriding shall be tested in the middle of the gear using the Quentin hardness method in accordance with GB/T9450. 7.9 The hardness requirements shall be in accordance with the product drawings. JRrE 9173-1999
7.9.1 The surface hardness of the common impeller should generally not be less than 56HC. It is allowed to detect on the tooth or end face. However, it is allowed to detect one point on a wheel 120° apart. The hardness difference of one point on the same impeller should not be greater than 3HRC: the measuring force is in accordance with GB/T230: 7.9.2 The hardness of the core of the common impeller should generally not be lower than HR. The Jimin breaking method is used to detect the intersection of the center load of the tooth and the tooth surface.
7.9.3 The hardness drop to the surface and the hardness drop to the core should not be too large. It should be checked according to GR/T8539 with a viscometer. Note: The hardness drop to the surface caused by excessive carbon or other excess vitreous material in the surface layer is allowed to exceed 50HV. 7.10 Heat treatment deformation becomes stable and should be coordinated with cold working to achieve the specified accuracy requirements.
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