GB/T 1239.2-2009 English PDF (GBT1239.2-2009)

This Document specifies the basic requirements and methods for the classification of forging functions, as well as the technical conditions, process requirements and acceptance basis for various forgings. This Document is applicable to metal free forgings, die forgings and special forgings.

GB/T 1239.2-2009
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 21.160
J 26
Replacing GB/T 1239.2-1989
Cold coiled helical springs technical specifications -
Part 2: Compressions spring
ISSUED ON: MARCH 16, 2009
IMPLEMENTED ON: NOVEMBER 01, 2009
Issued by: General Administration of Quality Supervision, Inspection and Quarantine;
Standardization Administration of the People's Republic of
China.
Table of Contents
Foreword ... 3
1 Scope ... 5
2 Normative references ... 5
3 Terms and definitions ... 6
4 Structure type ... 6
5 Technical requirements ... 6
6 Test methods ... 11
7 Inspection rules ... 14
8 Marking, packaging, transportation, storage ... 15
Annex A (informative) Legend ... 17
Cold coiled helical springs technical specifications -
Part 2: Compressions spring
1 Scope
This Part of GB/T 1239 specifies technical requirements, test methods,
inspection rules and packaging, marking, transportation and storage
requirements for helical compression spring of cold rolled round section cylinder. This Part is applicable to helical compression spring of cold rolled round section cylinder (hereinafter referred to as the spring). The cross-sectional diameter of the spring material is greater than or equal to 0.5 mm.
This Part is inapplicable to the spring of special requirements.
2 Normative references
The following documents contain the provisions which, through reference in this Part, become the provisions of this Part of GB/T 1239. For dated references, their subsequent amendments (excluding corrigendum) or revisions do not apply to this Standard. However, the parties who enter into agreement based on this Standard are encouraged to investigate whether the latest versions of these documents are applicable. For undated reference documents, the latest versions apply to this Standard.
GB/T 1805, Nomenclature of springs
GB/T 4357-1989, Carbon spring steel wires (neq JIS G3521:1984)
GB/T 16947, Helical spring fatigue testing standard
GB/T 18983, Oil - Hardened and tempered steel wire for mechanical springs (GB/T 18983-2003, ISO/FDIS 8458-3:1992, MOD)
GB/T 21652, Copper and copper alloy wire
JB/T 7367, Magnetic particle inspection for helical compression springs JB/T 7944, Coiled helical compression springs - Sampling inspection
JB/T 10802, Specification for shot peening of springs
required to be specified, it is calculated according to formula (1):
For springs that are not worn at both ends, when the compression height is required to be specified, it is calculated according to formula (2):
Where,
Hb - Compression height, in millimeters (mm);
n1 - Total number of turns, in turns;
dmax - Maximum material diameter (material diameter + maximum limit
deviation), in millimeters (mm).
5.3.7 Face grinding
The flattened part of the spring support ring with both ends and flattened tightly is not less than 3/4 of the turn. Its roughness is not greater than Ra12.5. The end thickness is not less than 1/8d.
5.4 Spring characteristics and limit deviation
5.4.1 Characteristics
The spring characteristics shall meet the requirements of 5.4.1.1 or 5.4.1.2. Generally, they are not used at the same time.
5.4.1.1 For the load at specified height or deformation, the spring deformation shall be between 20% and 80% of the deformation under the test load. When the spring requires grade 1 accuracy, the deformation of the load at the specified height shall be more than 4mm. However, the load under the
maximum deformation shall not be greater than the test load.
5.4.1.2 When the drawing stipulates that the spring stiffness needs to be measured, the spring deformation shall be between 30%~70% of the
deformation under the test load.
5.4.2 Limit deviation
5.4.2.1 The limit deviation of the load F under the specified height or deformation is in accordance with Table 7.
The surface treatment of the spring shall be indicated in the product drawing. The surface treatment medium and method shall comply with the corresponding environmental protection regulations. However, surface treatments that may cause hydrogen embrittlement shall be avoided as far as possible for the spring. 5.10 Other requirements
According to needs, the following requirements can be specified for the spring in the product drawing:
a) Shot peening;
b) Nondestructive inspection;
c) Fatigue test;
d) Heating and pressure treatment.
See Annex A for the spring legend. When there are special technical
requirements, it shall be stipulated by agreement between the supplier and the purchaser.
6 Test methods
6.1 Permanent deformation
Compress the spring with the test load three times. Measure the change of free height after the second and third compression. When the test load is greater than the compression load, the compression load is regarded as the test load. 6.2 Spring characteristics
The spring characteristics are measured on a spring testing machine with an accuracy of not less than ±1%. Measure the load or stiffness as specified in the drawing. When measuring the load under the specified deformation amount, the preload amount shall be negotiated between the supplier and the purchaser. The spring characteristics are measured after preloading the spring once. The preload height is the height corresponding to the test load or the compression height. The maximum compression load shall not exceed 1.5 times the
theoretical compression load.
The test load is calculated by formula (3). The test stress is shown in Table 9. between the supplier and the purchaser.
6.8 Surface quality
Use visual inspection or use a 5x magnifying glass to inspect the surface of the spring.
6.9 Surface treatment
The surface treatment of the spring shall be carried out in accordance with relevant standards or technical agreements.
6.10 Other requirements
The shot peening of the spring is carried out in accordance with the regulations of JB/T 10802.
The magnetic particle inspection of the spring shall be carried out in accordance with JB/T 7367.
The fatigue test of the spring shall be carried out in accordance with GB/T 16947.
Other special requirements such as spring treatment, heating and pressure, shall be implemented in accordance with product drawings and relevant
standards.
7 Inspection rules
7.1 Sampling inspection
The product acceptance sampling inspection shall be in accordance with the provisions of JB/T 7944, or it may be negotiated by both the supplier and the purchaser.
7.2 Product inspection items
a) Spring characteristics;
b) Outer diameter or inner diameter;
c) Free height;
d) Total number of turns;
e) Verticality or straightness;