ICS 21.160

Chinese standards

T/ZZB XXXX—XXXX

Hot rolled cylindrical spiral compression springs for high-voltage switches

Hot coiled helical compression springs for high voltage switch

XXXX - XX - XXrelease

XXXX - XX - XXimplementation

Released by Zhejiang Provincial Brand Building Federation

Group standards

目  次

Preface III

1　Range 1

2　Normative reference documents 1

3　Terms and definitions 2

4　Basic Requirements 2

5　technical requirement 2

6　test method 4

7　Inspection rules 5

8　Marking, packaging, transportation, and storage 6

9　Quality commitment 6

Preface

This standard is drafted based on the rules provided in GB/T 1.1-2020.

Some contents of this standard may involve patents, and the issuing authority of this standard does not assume the responsibility of identifying these patents.

This standard is proposed and managed by the Zhejiang Provincial Brand Building Federation.

This standard was developed under the leadership of the Zhejiang Institute of Standardization.

The main drafting unit of this standard is Zhejiang Jinchang Spring Co., Ltd.

The drafting unit of this standard is Zhejiang Mingfeng Spring Co., Ltd.

The main drafter of this standard is Fei Qingmin.

Leader of the expert review team for this standard: XXX.

This standard is interpreted by XXXXXXXX.

Hot rolled cylindrical spiral compression springs for high-voltage switches

Range

This standard specifies the scope, normative references, terminology and definitions, basic requirements, technical requirements, test methods, detection rules, markings, packaging, transportation, storage, and quality commitments of hot rolled cylindrical compression springs.

This standard is applicable to high-voltage switches and springs within the following size range. Springs beyond this size range can be referred to and adopted through consultation between the supply and demand parties:

——Free height: ≤ 900mm

——Spiral ratio: 3-12;

——Height to diameter ratio: 0.8-4;

——Effective number of turns: ≥ 3 turns;

——Pitch:<0.5D;

——Material diameter: 8mm~60mm;

——Spring diameter: ≤ 460mm.

Normative reference documents

The following documents are essential for the application of this document. For all referenced documents with dates, only the version with the date indicated applies to this document. The latest version (including all amendments) of any referenced document without a date is applicable to this document.

GB/T 224—2008   Determination of decarburization depth of steel

GB/T 230.1—2009   Rockwell hardness test for metallic materials Part 1: Test method

GB/T 231.1—2009   Metallic materials - Brinell hardness test - Part 1: Test method

GB/T 702—2017   Dimensions, shape, weight, and allowable deviations of hot-rolled steel bars

GB/T 1805—2001   Spring terminology

GB/T 6394—2017   Method for determining the average grain size of metals

GB/T 8170—2008   Rules for rounding off numerical values and representation and determination of limit values

GB/T 31214.1—2014   Spring shot peening Part 1: General principles

GB/T 10802—2007   Technical specification for spring shot peening strengthening

ISO 683-14—2004   Heat treated steel, alloy steel, and easily cut steel - Part 14: Hot rolled steel for quenched and tempered springs

ISO 9588—2007   Post coating treatment of metal and other inorganic coatings on steel to reduce the risk of hydrogen embrittlement

GB/T 1222—2016   Spring steel

GB/T 30512—2014   Requirements for prohibited substances in automobiles

GB/T 7367—2013   Magnetic particle testing method for cylindrical spiral compression springs

GB/T 23934—2015   Technical specifications for hot rolled cylindrical spiral compression springs for high-voltage switches

GB/T 13298—2015   Testing methods for microstructure of metals

GB/T 16947—2009   Specification for fatigue testing of spiral springs

GB/T 2827.1—2012   Sampling inspection procedures by attributes Part 1: Batch by batch inspection sampling plans indexed by acceptance quality limit (AQL)

Terms and definitions

The terms and definitions defined in GB/T 1805-2001 are applicable to this document.

Basic Requirements

Design and R&D

Develop design software for lightweight design and complete design optimization.

Stress shot peening and heating treatment to increase the residual stress of the spring;

Adopting secondary strengthening shot peening technology to improve the fatigue resistance of springs and researching the use of new equipment for rapid tempering;

The research on material heat treatment adopts advanced processes such as water quenching.

Material selection

raw material

The material should be alloy steel in GB/T 1222 or materials specified in ISO 683-14-2004 to manufacture springs.

Hot rolled bar material

Hot rolled bars with diameter limit deviation in accordance with Group 1 or Group 2 of GB/T 702-2017 should be selected.

Cold processing (cold drawing, turning, peeling, grinding)

Cold worked bar materials with maximum diameter deviation in accordance with Table 1 should be selected.

Maximum diameter deviation of cold worked bar materials

Springs should undergo stress relief tempering and surface strengthening treatment, and the hardness of the heat treatment should be assessed.

Springs with compressive stress ≥ 0.45Rm should be subjected to room temperature/heating standing treatment or strong pressure treatment.

Spring reinforcement should be surface shot peened in accordance with the requirements of GB/T 31214.1 and JB/T 10802 after grinding the spring.

Finite element analysis, corresponding analytical equipment for spectral analyzers.

The hardness of the spring after heat treatment should be evaluated, and its hardness should meet the requirements of the drawing. At the same time, the hardness difference of the same batch should be less than 3 HRC units.

It should be tempered martensite (oil quenched and tempered material), with a small amount of sorbite allowed.

Decarbonization of harmful substances is not allowed on the surface of the spring.

The original austenite grain size grade of spring products is generally not less than 5.

Springs should undergo shot peening strengthening treatment, which should be carried out in accordance with GB/T 31214.1 and JB/T 10802-2007. The shot peening strength should be (0.35-0.55) A, and the shot peening coverage rate should be ≥ 90%.

Craftsmanship and equipment

Detection capability

Should have the ability to inspect spring hardness, metallographic structure, decarburization, appearance and size, spring characteristic limit deviation, grain size, shot peening, and permanent deformation.

technical requirement

appearance

Appearance and size

The surface of the spring should not have harmful defects such as folds, grooves, cracks, hairlines, and oxide skin that affect its use.

Dimensional deviation

Free height

When specifying the load at a specified height or the spring characteristics at a specified height under a specified load, the free height is only for reference. If the load at the specified height or the spring characteristics at the specified height are not specified, the limit deviation of the free height should be in accordance with the provisions of Table 2. For the same level, the absolute value between the calculated value and the minimum value in the table should be taken, which is larger.

Maximum deviation of free height

Spring diameter

The outer diameter or inner diameter of the spring should be evaluated according to its purpose, and its limit deviation is shown in Table 3; At the same level, the absolute value between the calculated value and the minimum value in the table should be taken.

Limit deviation value of spring outer diameter or inner diameter

verticality

Springs can be tested for verticality at both ends or for verticality and parallelism based on one end. When either end is used as the detection reference, the tolerance requirements should be met.

The vertical tolerance of the outer side to the end face in the free state shall be as specified in Table 4.

Verticality tolerance of the outer side facing the end face

Compression height

When the deformation corresponding to the working load F2 of the spring is greater than 85% of the total deformation, the assessment of the compression height should be increased. The compression height should be less than or equal to (total number of turns -0.3) x steel wire diameter. When springs are produced using irregular cross-section materials, while meeting other geometric dimensions, an assessment of the compression height should be added, which should be less than or equal to (total number of turns -0.3) x the short axis size of the material cross-section.

Uniformity of pitch

When the equal pitch spring is compressed to 80% of the total deformation, the effective coils must not come into contact with each other.

The load when the spring is compressed to 80% of the total deformation should not exceed the experimental load.

Height limit deviation under specified load

Spring characteristic limit deviation

According to the provisions of Table 5, the height limit deviation under the specified load should take the larger absolute value between the calculated value and the minimum value for the same level limit deviation.

Height limit deviation under specified load

Load limit deviation at specified height

According to the provisions of Table 6, the maximum deviation value of the load at the specified height should be the larger absolute value between the calculated value and the minimum value for the same level limit deviation.

Load limit deviation value at specified height

Spring stiffness limit deviation

The maximum deviation of spring stiffness should be ± 10% F '. When the limit deviation of spring stiffness is specified, the height limit deviation under the specified load or the load limit deviation under the specified height are generally no longer specified.

Hot compression permanent deformation

The permanent deformation of the spring under hot compression shall not exceed 5% of the free height.

Restriction of Hazardous Substances

The limits of cadmium, lead, cadmium, and hexavalent chromium should comply with the provisions of GB/T 30512.

fatigue life 

Springs should undergo fatigue testing, with a requirement of no less than 20000 cycles. After the fatigue test, fracture is not allowed, and the loss rate of working load F2 should be less than or equal to 0.5%.

Total laps

The maximum deviation of the total number of turns is ± 1/4 turns

End face uniformity

Parallelism tolerance

When specifying the verticality of the two ends of the spring, parallelism is not considered. Select a section of perpendicularity and parallelism as the tolerance assessment. The parallelism tolerance between the two end circle planes shall be in accordance with the provisions of Table 7.

Parallelism tolerance

test method

appearance

Dimensional deviation

Visual inspection is generally used. Surface defects shall be inspected in accordance with the provisions of JB/T 7367.

Visual inspection is generally used. Surface defects shall be inspected in accordance with the provisions of JB/T 7367.

Free height

Appearance and size

Measure the free height using a universal or specialized measuring tool with appropriate accuracy, and the maximum value shall prevail. When the self weight affects the measurement of free height, the spring should be placed horizontally for measurement.

Spring diameter

Measure with a vernier caliper with a division value less than or equal to 0.02mm. Mark the outer diameter or pitch diameter on the drawing, and the maximum outer diameter shall prevail. The measuring inner diameter indicated on the drawing shall be based on the minimum value of the inner diameter.

verticality

Testing should be carried out in accordance with the provisions of 10.4.2 in GB/T 23934-2015.

Compression height

The load applied to determine the height of the compression should be less than or equal to 1.5 times the theoretical compression load. The spring height should be measured using a measuring tool with an accuracy of 0.02mm. The method of applying the load should be agreed upon by both the supply and demand parties.

Parallel pressure height

The load applied for measuring and pressing the height is less than or equal to 1.5 times the theoretical and pressing load. The height of the spring should be measured using a measuring tool with precision, and the method of applying the load should be agreed upon by both the supply and demand parties.

Spring characteristic limit deviation

Testing should be carried out in accordance with the provisions of 10.3 in GB/T 23934-2015.

Hot compression permanent deformation

Compress the spring with a working L2 height at a high temperature of 80 ℃ for 72 hours, and measure the changes in load at L2 height before and after the test.

Restriction of Hazardous Substances

The detection of harmful substance content in products should be carried out in accordance with GB/T 30512.

Number of spring coils

The method of determining the number of spring coils is determined through consultation between the supply and demand parties.

End face uniformity

The testing method for end face uniformity shall be determined through consultation between the supply and demand parties.

fatigue life 

Testing should be conducted on a fatigue testing machine in accordance with the provisions of GB/T16947.

hardness

Use a Rockwell hardness tester to test according to the provisions of GB/T 230.

Metallographic structure

Inspection should be carried out in accordance with the provisions of GB/T 13298

decarbonization 

The depth of decarburization layer shall be inspected using a metallographic microscope in accordance with GB/T 224 degree regulations.

Grain size

Testing should be carried out in accordance with the provisions of 10.9 in GB/T 23934-2015.

Shot peening

The testing method for spring shot peening strength and coverage shall be in accordance with GB/T 31214.1 and JB/T 10802-2007

Inspection rules

Classification of spring characteristic defects

The quality characteristics of springs are classified according to their impact on installation, performance, safety and reliability, as shown in Table 2.

Classification table for spring defect levels

8. 
   

The factory inspection shall be carried out in accordance with the provisions of GB/T 2828.1. Except for the height limit deviation under the specified load and the load limit deviation under the specified height, a full inspection shall be conducted. The rest shall be sampled once using a normal inspection sampling plan, calculated based on the number of non-conforming products per hundred units of product. The factory inspection items, inspection level (II), classification of non conformities, and acceptance quality limit (AQL) are 0.65%, which comply with the provisions of Table 9.

Factory inspection

Factory inspection items and discrimination

The type inspection shall be conducted in accordance with the provisions of GB/T 2828.1. Except for the height limit deviation under the specified load and the load limit deviation under the specified height, a full inspection shall be conducted. The rest shall be sampled once using a normal inspection sampling plan, calculated based on the number of non-conforming products per hundred units of product. The factory inspection items, inspection level (II), classification of non conformities, and acceptance quality limit (AQL) are 0.65%, which comply with the provisions of Table 9.

Type test

Trial production and identification of new or old products for factory production;

When there are significant changes in structure, materials, and processes that may affect product performance after formal production;

During normal production, type inspection should be conducted once a year;

When the product is discontinued for more than six months and production resumes;

When there is a significant difference between the factory inspection results and the previous type inspection;

When the national quality supervision agency proposes the requirement for type inspection.

Marking, packaging, transportation, and storage

Traceability identification

In the mass production process, springs should be marked with clear, clear, and specialized traceability marks. After packaging delivery, this should be passed on to the relevant parties.

The packaging box should ensure that it does not cause spring damage during normal transportation and is suitable for logistics operations.

After leaving the factory, under good protection, corrosion prevention, and ventilation storage conditions, the products inside the packaging box are moisture-proof and rust proof with a validity period of one year.

Springs should be cleaned and treated for corrosion before packaging, using sturdy and non permeable neutral packaging materials or customer specified packaging solutions. Fill the packaging box with springs or spring combinations of the same model. The packaging box should be accompanied by a product qualification certificate, which should indicate the product name, model, quantity, and production date.

The packaging box should ensure that it does not cause spring damage during normal transportation. The total weight of the box should be consistent with logistics operations. The exterior of the packaging box should be marked with the shipping address and receiving unit name, product name and model, quantity and weight, production date and batch number, and execution standard number.

packing

Transportation and storage

Quality commitment

The shelf life of this product is, provided that the user complies with relevant technical documents and agreements and operates normally. If any quality issues arise due to design or manufacturing reasons during the shelf life of the product, the design and manufacturing enterprise shall bear the responsibility

Manufacturing enterprises assume technical service responsibilities throughout the entire product lifecycle. Provide feedback on quality issues to customers (including end customers), respond within 24 hours, and promptly and properly resolve them through communication with customers.

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