JB/T 58702-2000 Cylindrical helical spring product quality classification JB/T58702-2000 standard download decompression password: www.bzxz.net

Mechanical Industry Standard of the People's Republic of China
JB/T58702-2000
Cylindrical Helical Spring
Product Quality Classification
(Internal Use)
Published on 2000-03-30
National Bureau of Machinery Industry
Implemented on 2000-10-01
JB/T58702-2000
This standard is a revision of JB/T58702-92 "Cylindrical Helical Spring Product Quality Classification". During the revision, the original standard was edited, and the main technical content remained unchanged. This standard replaces JB/T58702-92 from the date of implementation. This standard is proposed and managed by the National Technical Committee for Spring Standardization. The drafting unit of this standard: Mechanical Science Research Institute. 1 Scope
Machinery Industry Standard of the People's Republic of China
Cylindrical Helical Spring
Product Quality Grading
(Internal Use)
This standard specifies the quality grade of cylindrical helical spring products JB/T58702-2000
Replaces JB/T58702-92
This standard applies to the quality inspection, review, industry quality evaluation and product grade evaluation of cold-rolled cylindrical helical tension, compression, torsion springs and hot-rolled cylindrical helical tension, compression springs with a cross-sectional diameter greater than or equal to 0.5mm produced in accordance with national standards and industry standards.
2 Referenced 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/T1239.1—1989
GB/T1239.2—1989
GB/T1239.3—1989
GB/T1239.4—1989
JB/T58700—2000
3 Product quality grade classification
Technical conditions for cold-rolled cylindrical helical extension springsTechnical conditions for cold-rolled cylindrical helical compression springsTechnical conditions for cold-rolled cylindrical helical torsion springs Technical conditions for cylindrical helical springs
General rules for spring product quality classification
3.1 All cold-rolled or hot-rolled springs shall be divided into three grades: superior products, first-class products and qualified products according to their quality indicators, qualified quality levels and unit defect classification standards on the basis of complying with GB/T1239.1~1239.4. 3.2 Product quality indicators
Product quality indicators shall be in accordance with the provisions of Table 1, and the remaining items shall be in accordance with the requirements of GB/T1239.1~1239.4. 4 Inspection methods
4.1 Fatigue test and load loss
After the spring is compressed (stretched) three times to the test load P or the load specified in the drawing, it is tested on a special spring fatigue testing machine. The deformation of the spring should be between 20% and 80% of the deformation of the test load. After the test, the spring is continuous and has no cracks. The difference between the load after the test and the load after three compressions should not be greater than the load loss specified in Table 1. Approved by the State Bureau of Machinery Industry on March 30, 2000 and implemented on October 1, 2000
Cold rolled tensile
Cold rolled compression
Cold rolled torsion
Hot rolled cylindrical
Helical spring
4.2 Decarburization
Fatigue life
Load loss after fatigue test
Spring characteristics
Fatigue life
Load loss after fatigue test
Permanent deformation
Spring characteristics
Fatigue life
Free angle
Fatigue life
Fatigue Load loss after test
Permanent deformation
Spring characteristics
JB/T58702-2000
Superior products
Must have fatigue life requirements
≤5%P2
According to GB/T1239.1
1st level accuracy
Must have fatigue life requirements
≤4%P2
According to GB/T1239.2
1st level accuracy
Must have fatigue life requirements
According to GB/T1239.3
1st level accuracy
Must Fatigue life requirements must be met
≤4%P2
Only when specified in the drawing
≤6%P2
According to GB/T1239.1
Level 2 accuracy
Only when specified in the drawing
≤5%P
According to GB/T1239.2
Level 2 accuracy
Only when specified in the drawing
According to GB/T1239.3
Level 2 accuracy
Only when specified in the drawing
≤5%P2
According to the drawing||tt ||Qualified products
Only when the drawing specifies
≤7%P2
According to GBT1239.1
3rd grade accuracy
Only when the drawing specifies
≤6%P2
According to GBT1239.2
3rd grade accuracy
Only when the drawing specifies
According to GBT1239.3
3rd grade accuracy
Only when the drawing specifies
≤6%P2
The spring after quenching and tempering should be tested for decarburization, and samples should be taken from the working circle. Decarburization is checked with a 100x metallographic microscope. Place the specimen on the microscope stage, move the stage, observe the edge of the specimen for a week, and find the deepest decarburization part for measurement. Springs that have not been quenched or tempered are not tested for decarburization. 2
4.3 Hardness
JB/T58702—2000
Hardness inspection is performed by sampling on the working circle or test rod. Four points are punched on the sample, the first point is not tested, and the average value of the last three points is taken. Springs that have not been quenched or tempered are not tested for hardness.
4.4 Permanent deformation
It is performed on a special machine or spring testing machine. It is allowed to compress the spring three times to the height H under the test load with a tool, and measure the free height difference after the second and third compressions with a height gauge or vernier caliper. The difference is not greater than the provisions in Table 1. 4.5 Spring characteristics
It is tested on a spring testing machine with an accuracy of not less than 1%, and the spring is compressed (or stretched) once to the test load. The stiffness measurement should be determined by the ratio of the load difference to the deformation difference at two points between 30% and 70% of the deformation at the test load. 4.6 Diameter
Measure with a vernier caliper with a graduation value of 0.02mm. If the outer diameter or middle diameter is marked on the drawing, measure the outer diameter; if the inner diameter is marked, measure the inner diameter. 4.7 Free height, free length, torsion arm length, and hook length shall be measured with corresponding general measuring tools in accordance with the provisions of relevant standards. 4.8 Free angle
Measure with general or special measuring tools.
4.9 Verticality
Put the spring on a flat plate and measure with a wide-seat angle ruler. When the spring is under no-load condition, rotate it relative to the wide-seat angle ruler for one circle and then check the other end (from the end to 1/2 circle, check the adjacent second circle). Use a 100mm feeler gauge to determine the maximum deviation of verticality. 4.10 Surface defects
Inspect visually or with a 5x magnifying glass.
4.11 Hook position deviation
Put the spring flat on a common plate, and use a depth vernier caliper to measure the height between the front and back sides of the hook and the plate. Half of the height difference is the hook position deviation.
5 Inspection items, sampling plan, defect level and weighting 5
The inspection items, sampling plan, defect level and weighting of springs shall be in accordance with the provisions of Table 2. Table 2
Spot check items
Fatigue life
Spring characteristics or free length
Surface defects
Hook length of hook
Hook position
Weighted value
Number of samples
Spot check items
Fatigue life
Spring characteristics or free height
Permanent deformation
Surface defects
Verticality
Pitch uniformity
Fatigue lifewwW.bzxz.Net
Torque or free angle
Surface defects
Outer diameter or inner diameter
Free length| |tt||Torsion arm length
Spring characteristics or free length
Surface defects
Permanent deformation
Fatigue life
Spring characteristics or free height
Permanent deformation
Surface defects
Verticality
Straightness
Pitch uniformity
JB/T58702-2000
Table 2 (end)
Weighted value
Number of samples
Grade assessment
JB/T58702-2000
The grade assessment of tension springs shall be in accordance with the provisions of Table 3. The calculation of unit defect score F for cold-rolled tension, compression, torsion springs and hot-rolled compression shall be in accordance with the provisions of JB/T58700. Table 3
Grade name
Superior product
Qualified product
Unit defect score standard
1.030<2.588
F>2588
People's Republic of China
Mechanical industry standard
Column helical spring
Product quality classification
(internal use)
JB/T58702-2000
Published by the Mechanical Science Research Institute Printed by the China Academy of Mechanical Science (No. 2, Shouti South Road, Beijing, zip code 100044) Format 880X12301/16 Sheet 1/2 First edition in September 2000 Print run 1-500 Word count 12000 First printing in September 2000 Price 10.00 Yuan 2000-116 Mechanical Industry Standards Service Network: 1 http://www.jb.ac.cn
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