This standard specifies the technical requirements, inspection methods, inspection rules and marking, packaging, transportation and storage of valve push rods for internal combustion engines. JB/T 7294-1994 Technical requirements for valve push rods for internal combustion engines JB/T7294-1994 Standard download decompression password: www.bzxz.net

Mechanical Industry Standard of the People's Republic of China
JB/T7294-94
Valve Pushrods for Internal Combustion Engines
Published on July 18, 1994
Technical Conditions
Implemented on July 1, 1995
Ministry of Machinery Industry of the People's Republic of China
Mechanical Industry Standard of the People's Republic of China
Valve Pushrods for Internal Combustion Engines
Technical Conditions
1 Subject Content and Scope of Application
JB/T7294-94
This standard specifies the technical requirements, inspection methods, inspection rules and marking, packaging, transportation and storage of valve pushrods for internal combustion engines. This standard applies to valve pushrods for reciprocating piston internal combustion engines with a cylinder diameter of less than 200mm (hereinafter referred to as valve pushrods). 2 Reference standards
Metal tensile test method
GB/T230Metal Rockwell hardness test method
GB1184
GB1800
GB1958
GB2828
GB3191
GB5617
GB 8162
GB9450
3 Technical requirements
Technical conditions for high-quality carbon structural steel
Provisions for shape and position tolerances without tolerances General introduction to tolerances and fits Standard tolerances and basic deviations Shape and position weight tolerances Inspection regulations
Remote batch inspection Counting sampling procedures and sampling tables (applicable to continuous batch inspection) Aluminum and aluminum alloy extruded bracesbZxz.net
Determination of effective hardened layer depth after induction rate fire or flame tumbling of steel Structural seamless steel pipes
Determination and verification of effective hardened layer depth after carburization rate fire of steel parts 3.1 Valve push rods shall be manufactured according to product drawings and technical documents approved by the prescribed procedures. 3.2 Materials
3.2.1 The valve push rods of the integral structure shall adopt the 45 steel specified in GB699. 3.2.2 The two heads of the combined structure valve push rod are made of 20 and 45 steel specified in GB699. The rod is made of 20 and 45 steel specified in GB699, cold drawn (cold rolled) seamless steel pipe specified in GB8162, LY11 mixed material specified in GB3191, or other materials with strength not lower than the above materials.
3.3 The ball head and ball wide surface of the valve push rod shall be subjected to surface rate quenching or carburizing quenching, and the depth and hardness of the hardened layer shall meet the following requirements. 3.3.1 The depth of the hardened layer of 45 steel shall be greater than or equal to 1mm, and the hardness shall be greater than or equal to 48HRC. 3.3.2 The depth of the hardened layer of 20 steel shall be greater than or equal to 0.8mm, and the hardness shall be greater than or equal to 52HRC. 3.4 The two heads of the combined structure valve push rod are not allowed to loosen. The welds of resistance welding and friction welding must be firm, and the weld strength shall not be less than 60% of the tensile strength of the parent material.
3.5 The tolerance of the total length of the valve push rod shall not be less than IT13 level specified in GB1800. 3.6 The tolerance of the radius of the ball socket of the valve push rod head shall not be less than IT12 level specified in GB1800. 3.7 The roughness threshold R. value of the working surface of the valve push rod shall be 1.6μm. 3.8 The straightness tolerance level of the valve push rod element line shall not be less than 12 level specified in GB1184. 3.9 The valve push rod shall be free of defects such as cracks, flash, burrs, burning, rust, etc. Approved by the Ministry of Machinery Industry on July 18, 1994
Implemented on July 1, 1995
JB/T 729494
3.10 The service life of the valve push rod shall not be less than the overhaul period of the internal combustion engine. 4 Inspection method
4.1 Depth of hardened layer and hardness
4.1.1 Hardness shall be in accordance with the provisions of GB/T230. The measurement of spherical hardness can detect spherical specimens under the same conditions. If the outer cylindrical surface of the same state is used instead, the measuring points shall be evenly distributed on the outer cylindrical surface, and the measuring points shall not be less than three points. 4.1.2 The depth of hardened layer shall be measured in accordance with the provisions of GB5617 and GB9450. 4.2 Weld tensile strength
The tensile strength test of welds shall be in accordance with the provisions of GB228. 4.3 Dimensional tolerance
The length measurement part is two planes perpendicular to the outer slow axis. The measuring plane should be able to cover the end face of the valve push rod. 4.4 Surface roughness
The surface roughness test adopts the roughness sample comparison method, and other methods can also be used. 4.5 Straightness
Straightness inspection shall be in accordance with the provisions of GB1958,
4.6 Appearance quality
Observe with naked eyes.
5 Inspection rules
5.1 Valve push rods shall be inspected and qualified by the quality inspection department of the manufacturer before they can leave the factory. 5.2 The manufacturer shall conduct regular sampling inspections on valve push rods. The inspection items are 3.2, 3.3, 3.4, 3.5, 3.6, 3.7 and 3.8. The sampling results shall comply with the provisions of the above items.
5.3 The period of regular sampling inspection shall be determined by the quality inspection department of the manufacturer. 5.4 When the ordering unit conducts sampling inspection on the quality of valve push rods, the sampling plan shall be in accordance with the one-time sampling plan specified in GB2828, with the general inspection level of 1 and the qualified quality level AQL of 6.5. It may also be carried out according to other sampling plans agreed upon by the supply and demand parties. 5.5 During the warranty period, if the valve push rod is damaged due to poor manufacturing, the manufacturer shall replace it free of charge. 6 Marking, packaging, transportation and storage
6.1 The factory marking of the valve push rod shall be in accordance with the product drawings. 6.2 The valve push rod must be cleaned, oil-sealed or otherwise treated to prevent rust, and packed in a packaging box lined with waterproof paper or plastic film bags. Under normal storage conditions, the valve push rod should be guaranteed to be rust-free within 12 months. 6.3 The packaging basin should be accompanied by a product quality certificate signed by the manufacturer's inspector, and the certificate should indicate: manufacturer name and trademark:
b. Internal combustion engine model and part name:
c. Inspection date.
6.4 The valve push rod packed in the packaging box is then packed in a dry packaging box lined with waterproof paper, and it is guaranteed not to be damaged during normal transportation. The total weight of each box shall not exceed 50kg. If the ordering unit agrees, simple packaging can also be used. 6.5 The surface of the packaging box should be marked with:
Manufacturer name and address:
Internal combustion engine model and part name;
Quantity:
Gross weight, kg;
"Handle with care", "Moisture-proof\" and other signs: Factory date,
JB/T7294~-94
6.6 Valve push rods should be stored in a ventilated and dry warehouse without corrosive substances. Additional remarks:
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, Zhuzhou Internal Combustion Engine Parts Factory, and Mianyang Internal Combustion Engine Parts Factory. The main drafters of this standard are Weng Zuliang, Feng Chaoming, and Lin Zhongxing. 3
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