JB/T 6728-1993 Technical requirements for camshafts for internal combustion engines
Some standard content:
Mechanical Industry Standard of the People's Republic of China
JB/T6728-93
Technical Conditions for Camshafts of Internal Combustion Engines
Issued on July 29, 1993
Ministry of Machinery Industry of the People's Republic of China
Implementation on January 1, 1994
Mechanical Industry Standard of the People's Republic of China
Technical Conditions for Camshafts of Internal Combustion Engines
Subject Content and Scope of Application
JB/T 6728-93
This standard specifies the technical requirements, inspection methods, inspection rules and marking, packaging, transportation and storage of camshafts of internal combustion engines. This standard applies to valve timing camshafts (hereinafter referred to as camshafts) for reciprocating piston internal combustion engines with a cylinder diameter less than or equal to 200mm.
Referenced standards
GB1184
GB1348
GB1800
GB1958
GB2828
GB3077
GB5617
GB9441
GB9450
GB10561
GB11354| |tt||.JB3021
JB/T6729
ZBJ36009
ZBJ36010
Technical requirements
Method for determining the depth of decarburized layer in steel
Metal tensile test method
Metal Rockwell hardness test method
Metal Brinell hardness test method
Technical conditions for high-quality carbon structural steel|| tt||Provisions for shape and position tolerances without tolerance notes Ductile iron parts
General introduction to tolerances and fits
Standard tolerances and basic deviations
Provisions for shape and position tolerance testing
Counting sampling procedures and sampling tables for batch inspection (applicable to inspection of continuous batches)Technical conditions for alloy structural steels
Determination of effective hardened layer depth after induction quenching or flame quenching of steelMetallographic examination of ductile iron
Determination and verification of effective hardened layer depth after carburizing and quenching of steel partsMicroscopic evaluation method for non-metallic inclusions in steelDetermination and metallographic examination of nitriding layer depth of steel partsMetallographic standard for isothermal quenching of rare earth magnesium ductile ironMagnetic particle inspection of crankshafts and camshafts for internal combustion engines
Metallographic examination of steel parts by induction quenching
Metallographic examination of pearlite ductile iron parts by induction quenchingCamshafts should be manufactured in accordance with product drawings and technical documents approved through the prescribed procedures. 3.2 Material requirements
3.2.1 The camshaft shall be made of 15Cr, 20Cr, 20Mn2, 45Mn2 steel specified in GB3077, 20, 45 steel specified in GB699, QT600-3 specified in GB1348 or other materials such as alloy cast iron that meets the use requirements. 3.2.2
The carbon content of steel shall be carefully selected.
Standard purity of non-metallic inclusions, brittle inclusions and plastic inclusions in steel shall not exceed 2.515Cr, 20Cr, 20Mn2, 20 steel camshafts specified in GB10561 Approved by the Ministry of Machinery Industry on July 29, 1993
Implemented on January 1, 1994
JB/T672893
3.2.4.1 For the camshafts of the above-mentioned grades, the bearing journals and cam surfaces shall be carburized and quenched or carbonitrided, with a hardened layer depth of 0.8~1.5mm and a hardness of 58~63HRC. 3.2.4.2 The metallographic structure of the hardened layer shall be fine needle-shaped martensite, a small amount of retained austenite and carbon (nitride), and continuous network cementite and decarburized layer are not allowed to exist. The carbon or carbon-nitrogen concentration gradient in the carburized layer or carbonitrided layer should smoothly transition to the core, and the sum of the depth of the hypereutectoid layer and the eutectoid layer should not be less than two-thirds of the carburized layer depth. 3.2.545Mn2, 45 steel camshaft
3.2.5.1 The above-mentioned grades of materials should be quenched and tempered or normalized, with a quenched and normalized hardness of 207~302HBS and a normalized hardness of 170~241HBS; the bearing journal (with sliding bearings) and cam surface should be surface quenched, with a hardened layer depth of 1.5~6mm and a hardness of 53-63HRC.
2 The metallographic structure of the hard layer shall be qualified according to the provisions of ZBJ36009, and grades 3 to 8 shall be qualified. 3.2.5.2
18%.
After heat treatment, the service strength of the plated steel camshaft shall be greater than or equal to 470MPa, and the relative elongation shall be 8, which is greater than or equal to QT600-3 ductile iron camshaft.
3. 2. 7. 2
The ductile iron camshaft shall be isothermally quenched, or the cam surface shall be surface quenched after overall normalizing. The surface hardness of the isothermally quenched camshaft shall be 43~51HRC, and the metallographic structure shall meet the following requirements: the graphite spheroidization level shall be 1~4;
the graphite spheroidal diameter shall be 58;
no more than 2% of free cementite and no more than 2% of phosphorus eutectic are allowed to exist, but the total amount shall not exceed 3%; the bainite structure shall be lower bainite, with a level of 1~3. 3. 2. 7. 3
The surface rate quenched camshaft has a pre-treatment normalizing hardness of 220~290HBS, and the metallographic structure of the camshaft body should meet the following requirements: the graphite spheroidization level is 1~4;
the graphite spheroid size is 5~8;
the pearlite content is not less than pearlite level 75;
no more than 2% of free carburized and no more than 2% of phosphorus eutectic are allowed to exist, but the total amount should not exceed 3%. After the surface rate quenching of the bearing journal and cam surface, the depth of the hardened layer is 1.5~5mm, the hardness of the hardened layer is 43~51HRC, and the metallographic structure of the hardened layer is in accordance with the provisions of ZBJ36010, and the 3~6 levels are qualified. 3.2.8 Alloy cast iron camshaft
3.2.8.1 The bearing journal and cam surface of alloy cast iron camshaft shall be surface quenched or cold-shocked. 3.2.8.2 The tensile strength of alloy cast iron camshaft shall be greater than or equal to 250MPa. 3.2.8.3
When surface quenched, the depth of hardened layer shall be 1.5～5mm, the hardness of hardened layer shall be 53～58HRC, and its metallographic structure shall be fine needle-shaped and medium needle-shaped tempered martensite and carbide. When the surface of cam profile is cold-shocked, the depth of cold-shock layer shall be 2.5～7mm, the hardness shall be greater than or equal to 45HRC, and its metallographic structure shall be uniformly distributed fine needle-shaped eutectic carbide and a small amount of light body. 3.3 The dimensional tolerance grade of the diameter of each supporting journal of the camshaft shall not be lower than IT7 specified in GB1800. 3.4 The angular deviation of the plane formed by the highest point of the cam profile and the base circle axis to the center plane of the timing gear keyway or the axis of the locating pin hole shall not be greater than ±30°, and the camshaft of the six-cylinder engine is allowed to be ±45'. 3.5 Tolerance of shape and position of the camshaft
3.5.1 The cylindrical tolerance grade of the supporting journal shall not be lower than Grade 7 specified in GB1184. 3.5.2 When supporting the journals at both ends, the circular runout of the supporting journal shall comply with the following provisions: When the shaft length is less than or equal to 1000mm, its circular runout tolerance grade shall not be lower than Grade 8 specified in GB1184. 3.5.2.1
3. 5. 2. 2
When the shaft length is greater than 1000mm, its circular runout tolerance grade shall not be lower than grade 9 specified in GB1184. When supporting the journals at both ends, the circular runout tolerance of the cam base circle is 0.04mm, and the circular runout tolerance of the thrust end face is 0.03mm. The symmetry of the center plane of the timing gear keyway to the axis of the journal where it is located shall not be lower than grade 8 specified in GB1184. 3.6
JB/T 672893
The surface roughness parameter R of the main parts of the camshaft shall comply with the provisions of Table 1. Table 1
Cam surface (cast iron)
Cam surface (steel)
Support journal surface
Support journal surface (rolling bearing)
Timing gear journal surface
Thrust end surface
Cam lift deviation is in accordance with the product drawing. 10% lift point lift tolerance is allowed. 3.7
Surface roughness parameter R value
3.8 Camshaft non-machined surface: Steel camshafts are not allowed to have defects such as oxide scale, folding, interlayer, cracks, and insufficiency; cast camshafts are not allowed to have defects such as shrinkage, shrinkage, cracks, slag inclusions, scars, and cold shuts. 3.9 Camshaft machined surfaces are not allowed to have defects such as burns, scratches, pores, shrinkage, cracks, depressions, spots, etc. 3.10 Camshafts should be subjected to magnetic particle inspection.
The service life of the camshaft should not be less than the service life of the internal combustion engine. 3.11
Camshaft warranty period: 3.11
Camshaft warranty period: 3.1112
Within 12 months from the date of the camshaft or the cumulative working time is 1000h for diesel engines for vehicles and 2000h for diesel engines for other purposes, if the camshaft is damaged and the record is available, the manufacturer shall replace it for the user free of charge. Note: The warranty period shall terminate if either of the two warranty conditions expires. 4
Test method
4.1 Hardness
4.1.1 Mechanical hardness test
4.1.1.1 Sampling position: Sampling on the camshaft body, 4.1.1.2 Test method: According to the provisions of GB230 and GB231. 2 Non-destructive testing can also be used.
4.2 Mechanical properties
1 Sampling position: Cut off from the camshaft body and take 3 samples. Ductile iron samples shall comply with GB1348. 4.2. 1
Test method: Tensile test shall comply with GB228. 4.3 Metallographic microstructure
4.3.1 Sampling location: The hardened layer structure is cut at the cam profile, and the sample size is 15×15×cam width. The main structure sample can be cut at other locations.
4.3.2 Test method: Decarburized layer is in accordance with GB224; ductile iron camshaft is in accordance with GB9441, JB3021 and ZBJ36010; steel camshaft is in accordance with ZBJ36009.
4.4 Depth of hardened layer
1 Sampling location: Cut at the cam profile and support journal. 4. 4. 1
Test method: According to the provisions of GB9450, GB5617 and GB11354, or cut the sample along the axis direction, and then etch with 3%~5% nitric acid alcohol solution on the cut surface, and measure with a metallographic microscope to 50% martensite. 4.5 Dimensions
The diameter of the camshaft bearing journal is measured with a measuring tool with an accuracy of not less than ±0.004mm
The angular deviation between the plane formed by the highest point of the cam profile and the base circle axis and the center plane of the timing gear keyway or the positioning pin hole shall be measured with an optical dividing head, a four-level gauge block, a height gauge, and a lever micrometer. 3
JB/T672893
4.5.3 The cam lift deviation shall be measured on the camshaft inspection instrument. 4.6 Shape and position tolerance
The shape and position tolerance of each machined part on the camshaft shall be tested in accordance with GB1958. Surface roughness
The cam surface and bearing journal surface roughness of the camshaft shall be measured with a surface roughness meter, and other methods are also allowed. 4.8 Surface macro quality
The surface macro quality of the camshaft shall be observed with the naked eye. 4.9 Magnetic particle inspection
Performed in accordance with JB/T6729.
5 Inspection rules
Each camshaft shall be inspected and qualified by the inspection department of the manufacturer before it can be shipped out of the factory. 5.1
5.2The manufacturer shall conduct regular random inspections on the camshafts. The inspection items are 3.2~3.4, 3.5.1, 3.5.2, 3.6~3.9, and the inspection results shall meet the above provisions.
5.3The period of regular random inspections shall be determined by the quality inspection department of each manufacturer. 5.4 When the ordering unit conducts random inspection of the camshaft quality, the sampling method shall comply with the provisions of GB2828, or other sampling methods agreed upon by the supply and demand parties.
6 Marking, packaging, transportation, purchase and storage
Each camshaft shall be marked with the factory mark. The marking position, size and method shall comply with the product drawings. Care shall be taken to prevent the parts from being photographed. The camshaft must be cleaned, oil-sealed and packaged. The validity period of the oil seal shall not be less than 12 months. The packaged camshaft shall be placed in a packaging box lined with waterproof paper or plastic film. Ensure that the parts are not damaged during transportation. Packing box 6.3
The weight of each box shall not exceed 50kg (the weight of a single piece is not limited). The packaging box shall be accompanied by a product quality certificate signed and stamped by the manufacturer's inspector. The product quality certificate shall indicate: 6.41
Manufacturer name, factory mark and address; internal combustion engine model, part name and part number; inspection date.
The outer surface of the packaging box should be marked with:
Manufacturer name, factory logo and address; internal combustion engine model and part name;
Packing date, gross weight or quantity;
"Handle with care", "Moisture-proof" and other signs. Camshafts should be stored in ventilated and dry warehouses. 6.6
Additional instructions:
This standard was proposed and managed by the Shanghai Internal Combustion Engine Research Institute of the Ministry of Machinery Industry. This standard was drafted by the Shanghai Internal Combustion Engine Research Institute of the Ministry of Machinery Industry. The main drafter of this standard is Weng Zuliang.
From the date of implementation of this standard, NJ25-86 "Technical Conditions for Camshafts" will be invalid. 4
People's Republic of China
Mechanical Industry Standard
Technical Specifications for Camshafts of Internal Combustion Engines
JB/T6728-93
Published by the Machinery Standardization Research Institute of the Ministry of Machinery Industry Printed by the Machinery Standardization Research Institute of the Ministry of Machinery Industry (P.O. Box 8144, Beijing
Copyright reserved
Edited by the Ministry of Industry and Information Technology 100081
No reproduction allowed
Sheet 1/2 Number of words 8,000
Format 880×12301/16
First printing in December 1993
First edition in December 1993
Print number 00,001-500 Price 3.00 yuan
No. 12543
The weight of each box shall not exceed 50kg (the weight of a single piece is not limited). The packaging box shall be accompanied by a product quality certificate signed by the manufacturer's inspector. The product quality certificate shall indicate: 6.41
Manufacturer name, factory mark and address; internal combustion engine model, part name and part number; inspection date.
The outer surface of the packaging box shall be marked with:
Manufacturer name, factory mark and address; internal combustion engine model and part name;
Packing date, gross weight or quantity;
"Handle with care", "Moisture-proof" and other signs. Camshafts should be stored in ventilated and dry warehouses. 6.6
Additional instructions:
This standard was proposed and managed by the Shanghai Internal Combustion Engine Research Institute of the Ministry of Machinery Industry. This standard was drafted by the Shanghai Internal Combustion Engine Research Institute of the Ministry of Machinery Industry. The main drafter of this standard is Weng Zuliang.
This standard shall be invalidated as of the date of implementation of NJ25-86 "Technical Conditions for Camshafts". 4bZxz.net
People's Republic of China
Mechanical Industry Standard
Technical Conditions for Camshafts for Internal Combustion Engines
JB/T6728-93
Published by the Mechanical Standardization Research Institute of the Ministry of Machinery Industry Printed by the Mechanical Standardization Research Institute of the Ministry of Machinery Industry (P.O. Box 8144, Beijing
Copyright reserved
Edited by the Ministry of Machinery Industry 100081
No reproduction
Sheet 1/2 Number of words 8,000
Format 880×12301/16
First printing in December 1993
First edition in December 1993
Printing quantity 00,001-500 Pricing 3.00 yuan
No. 12543
The weight of each box shall not exceed 50kg (the weight of a single piece is not limited). The packaging box shall be accompanied by a product quality certificate signed by the manufacturer's inspector. The product quality certificate shall indicate: 6.41
Manufacturer name, factory mark and address; internal combustion engine model, part name and part number; inspection date.
The outer surface of the packaging box shall be marked with:
Manufacturer name, factory mark and address; internal combustion engine model and part name;
Packing date, gross weight or quantity;
"Handle with care", "Moisture-proof" and other signs. Camshafts should be stored in ventilated and dry warehouses. 6.6
Additional instructions:
This standard was proposed and managed by the Shanghai Internal Combustion Engine Research Institute of the Ministry of Machinery Industry. This standard was drafted by the Shanghai Internal Combustion Engine Research Institute of the Ministry of Machinery Industry. The main drafter of this standard is Weng Zuliang.
This standard shall be invalidated as of the date of implementation of NJ25-86 "Technical Conditions for Camshafts". 4
People's Republic of China
Mechanical Industry Standard
Technical Conditions for Camshafts for Internal Combustion Engines
JB/T6728-93
Published by the Mechanical Standardization Research Institute of the Ministry of Machinery Industry Printed by the Mechanical Standardization Research Institute of the Ministry of Machinery Industry (P.O. Box 8144, Beijing
Copyright reserved
Edited by the Ministry of Machinery Industry 100081
No reproduction
Sheet 1/2 Number of words 8,000
Format 880×12301/16
First printing in December 1993
First edition in December 1993
Printing quantity 00,001-500 Pricing 3.00 yuan
No. 1254
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