JB/T 51121-2000 Diesel Engine Low-pressure Metal Oil Pipe Assembly Product Quality Classification JB/T51121-2000 Standard Download Decompression Password: www.bzxz.net

Mechanical Industry Standard of the People's Republic of China
JB/T51120-2000
Diesel Engine High Pressure Fuel Pipe Assemblies
Product Quality Classification
(Internal Use)
Published on 2000-08-31
National Machinery Industry Bureau
Implemented on 2000-12-01
JB/T511202000
This standard is a revision of JB/T51120.1~51120.3-94 "Product Quality Classification of High Pressure Fuel Pipe Assemblies for Diesel Engines". During the revision, only editorial changes were made to the original standard, and the main technical content remained unchanged. This standard replaces JB/T51120.1~51120.3-94 from the date of implementation. This standard is proposed and managed by the National Technical Committee for Standardization of Internal Combustion Engines. The drafting units of this standard are Shanghai Internal Combustion Engine Research Institute and Hangzhou Jiangnan Oil Pipe Co., Ltd. The main drafters of this standard are Qu Junming, Xu Changshun and Chen Linshan. This standard was first issued in October 1987, and the standard number was adjusted to JB/T51120.1~51120.3-941 in September 1994.
Machinery Industry Standard of the People's Republic of China
Diesel Engine High-Pressure Oil Pipe Assembly
Product Quality Classification
(Internal Use)
JB/T51120—2000
Replaces JB/T51120.1-511203—94
This standard specifies the quality indicators, test methods and inspection rules of diesel engine high-pressure oil pipe assemblies (hereinafter referred to as high-pressure oil pipe assemblies).
This standard applies to the quality inspection and assessment of high-pressure fuel pipe components for dry diesel engines 2 Reference standards
The provisions contained in the following standards constitute the provisions of this standard through reference in this standard. When this standard is published, the versions shown are valid. All standards will be revised, and parties using this standard should explore the possibility of using the latest versions of the following standards. GB/T699—1999
GB/T2828—1987
JB/T6014—2000
JB/T8120.1—2000
3 Quality indicators
High-quality carbon structural steel
Batch inspection counting sampling procedures and sampling tables (applicable to continuous batch inspection) Technical conditions for diesel engine high-pressure oil pipe assemblies
Steel pipes for high-pressure oil pipes of compression ignition engines Part 1: Technical conditions for single-wall cold-drawn seamless steel pipes 3.1 High-pressure oil pipe assemblies shall be manufactured according to product drawings and technical documents approved by the prescribed procedures and comply with relevant standards 3.2 The materials and hardness of high-pressure oil pipes, sheaths, pipe nuts and compression washers shall comply with the provisions of Table 1. If other materials are used instead, their mechanical properties shall not be lower than the material performance indicators specified in Table 1. Table 1
Parts name
High-pressure oil pipe
Compression washer
Pipe union nut
High-quality carbon structural steel
High-quality carbon structural steel
High-quality carbon structural steel
Recommended steel grade
Standard number
JB/T8120.1
3.3High-pressure oil pipe assembly inner surface cleanliness limit: 5mg/m for qualified products and 4.5mg/m for first-class products. Recommended hardness
26-31HRC
26-31HRC
3.4High-pressure oil pipe assemblies shall be subjected to pressure resistance test with a test pressure of 100MPa and a duration of not less than 30s. No leakage, rupture or permanent deformation shall be allowed.
3.5 The installation dimensions of the high-pressure oil pipe assembly shall comply with the provisions of the agreement between the supply and demand parties. 3.6 The inner diameter size deviation of the high-pressure oil pipe shall comply with the provisions of Chapter 3 of JB/T8120.1-2000. Approved by the State Bureau of Machinery Industry on August 31, 2000 and implemented on December 1, 2000.
JB/T51120-2000
3.7 The angle deviation of the high-pressure oil pipe sealing cone surface is 1°. The surface roughness R of the high-pressure oil pipe sealing cone surface is 1.6um. 3.8
The surface roughness R of the shoulder foot of the pipe sleeve nut is 3.2um. 3.10
The thread tolerance zone of the nut is 6H grade, and the thread surface roughness R is 3.2μm. The tolerance of the cone surface of the high-pressure oil pipe to the center line circle runout: qualified products are 0.30mm, and first-class products are 0.25mm. 3.11
The maximum dimensional deviation of the outer diameter of the high-pressure oil pipe after upsetting is +0.5mm. 3.12
The circular runout tolerance of the nut guide hole to the thread center line is 0.20mm. 3.13
3.14 The dimensional deviation of the outer diameter of the high-pressure oil pipe: when d<8mm, it is ±0.06mm; when d≥8mm, it is ±0.10mm. 3.15 The reduction of the inner diameter caused by the upsetting of the high-pressure oil pipe should be trimmed. The dimensional deviation of the inner hole D within a length range of 20mm from the upsetting end face: when D is 1.5~3mm, it is mm; when D>3mm, it is amm. 3.16 The sealing cone surface of the high-pressure oil pipe should be flat and free of scratches, bumps and cracks. The surface of the oil pipe sheath, compression washer and pipe union nut should be oxidized or zinc-plated passivation. The galvanized layer should be uniform, firm, bright in color, and free of defects such as bubbles, peeling and bottom exposure. Slight pinch marks are allowed. Rust is not allowed on the inner and outer surfaces. 3.17 The service life of the high-pressure oil pipe assembly under normal use conditions should be consistent with that of the matching diesel engine. 4 Test method
4.1 Precision inspection of the main parts of the high-pressure oil pipe assembly The equipment, instruments and measuring tools used in the inspection must be approved by the prescribed procedures or recognized in the industry and within the validity period. The surface roughness of the parts of the high-pressure oil pipe assembly is checked with a profilometer or a surface roughness comparison sample. 4.2 Determination of the cleanliness of the inner surface of the high-pressure oil pipe assembly 4.2.1 The measurement location, equipment, cleaning fluid, preparation work, and operating steps shall comply with the provisions of 5.4 in JB/T6014-2000. 4.2.2 Calculation of impurities
Wtotal=G,-G
Wherein: W is the total mass of impurities, mg;
G is the mass of the filter membrane before filtration, mg;
Gz is the mass of the filter membrane after filtration, mg.
4.2.3 Cleanliness calculation shall be in accordance with the provisions of 5.4.7 of JB/T6014-2000. 4.3 Pressure test
The pressure test of high-pressure oil pipe components shall be carried out on a hydraulic test bench. After the test pressure reaches the specified value, the duration shall be not less than 30S. Observe whether there is leakage, rupture or permanent deformation in all parts of the oil pipe. 4.4 Measurement of the inner diameter of high-pressure oil pipe
The sample shall be randomly selected during the blanking process and measured with a smooth plug gauge with a through gauge length of not less than 20mm approved by the prescribed procedure. 4.5 Inspection of material and hardness of high-pressure oil pipe components 4.5.1 The material of each part can be inspected in the factory physical and chemical laboratory or professional testing unit. 4.5.2 For parts that cannot be tested for hardness with finished products, it is allowed to sample the materials being processed on the production line for testing. 5 Inspection rules
5.1 Classification of unqualified products
JB/T51120—2000
According to GB/T2828, the quality characteristics of the inspected products that do not meet the standards or drawing requirements are called unqualified. According to their importance to product quality, unqualified products are generally divided into: Class A unqualified products, Class B unqualified products, and Class C unqualified products. Class A unqualified products: extremely important quality characteristics of products do not meet the requirements: Class B unqualified products: important quality characteristics of products do not meet the requirements: Class C unqualified products: general quality characteristics of products do not meet the requirements. The classification of unqualified product quality characteristics of high-pressure oil pipe components is based on Table 2. Table 2
Classification of non-conformance
2 Acceptable quality level AQL
Pressure test
Quality characteristics
Inner surface cleanliness of high-pressure oil pipe assembly
Service life
Material of high-pressure oil pipe
Material and hardness of pipe nut
Dimensional deviation of inner diameter of high-pressure oil pipe
Surface roughness of sealing cone of high-pressure oil pipe
Within 30mm length from the end face of high-pressure oil pipe joint Inner hole size deviation High-pressure oil pipe sealing cone angle deviation
High-pressure oil pipe cone surface centerline runout High-pressure oil pipe assembly installation size
High-pressure oil pipe swell after the maximum size deviation of the outer circle High-pressure oil pipe outer diameter size limit deviation
High-pressure oil pipe assembly packaging
Hardness of compression washerwwW.bzxz.Net
High-pressure oil pipe assembly surface quality
High-pressure oil pipe assembly is divided into two grades: qualified products and first-class products, and the AQL value is specified separately (see Table 3). 5.3
Sampling plan
Use the normal inspection single sampling plan (see Table 3), and AcRe in the table is calculated by the point method. Table 3
Unqualified classification
Inspection level
Sample size code
Sample size n
Qualified products
First-class products
N-281~500
5.4 Inspection batch N
JB/T51120—2000
The specified batch N is 281~500 pieces. The inspection batch shall not be less than the lower limit of the specified batch. If it is greater than the upper limit of the specified batch, the product batch shall be divided into several batches, and one of the batches shall be randomly selected for sampling inspection. When sampling by users or sales agencies, the batch size is not limited. 5.5 Inspection level
Special inspection level S-1 is used for Class A nonconformities, and general inspection level I is used for Class B and C nonconformities. 5.6 Sample extraction
Samples should usually be randomly extracted from user units, commercial departments or parts companies, and are not subject to the lower limit of the batch range. If samples are extracted from products that have been put into storage in the recent period (within half a year), the batch range specified in 5.4 must be strictly followed. 5.7 Product quality grade assessment
5.7.1 Sample inspection
Samples are inspected and assessed according to the nonconformity classification specified in Table 2 and the sampling plan specified in Table 3, and in accordance with the provisions of Chapter 4. 5.7.2 Batch assessment
After all samples are inspected, if the number of nonconformities in a certain category is less than or equal to Ac, the category is judged as qualified: when the number of nonconformities in a certain category is greater than or equal to Re, the category is judged as unqualified. When the number of nonconformities in all categories is qualified, the batch of products is judged as qualified.
5.7.3 Quality Grade Assessment
5.7.3.1 After all samples have been inspected, when the number of unqualified items of each category in the sample is less than or equal to Ac of first-class products, the inspected product shall be assessed as a first-class product; when the number of unqualified items of each category in the sample is less than or equal to Ac of qualified products, the inspected product shall be assessed as a qualified product. When the number of unqualified items of one category in the sample is greater than or equal to Re of qualified products, the inspected product shall be assessed as an unqualified product. 5.7.3.2 After a product is assessed as an unqualified product, it is allowed to be re-inspected once after half a year. If the re-inspection is qualified, it can still be assessed as a qualified product, but it shall not be assessed as a first-class product.
Mechanical Industry Standard
Diesel Engine High-Pressure Fuel Pipe Assembly
Product Quality Grading
(Internal Use)
JB/T51120—2000
Published and Distributed by the Mechanical Science Research Institute
Printed by the Mechanical Science Research Institute
(No. 2, Shouti South Road, Beijing, Postal Code 100044)*
1/16 Sheet 1/2| |tt||2Word count 1Q000
Format 880×1230
First edition in November 2000
Print run 1-500
First printing in November 2000
Price 1000 yuan
2000-150
Mechanical Industry Standard Service Network: http/kvwwJB.ac.cn000202
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