JB/T 4378.2-1999 General technical conditions for metal cold stamping parts
Some standard content:
JB/T 4378.2—1999
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This standard is a revision of JB4380--87 "Metal Cold Stamping Parts Statement
General Technical Conditions".
This standard has changed from JB4380--87 in the following main technical contents: 1) Added scope and reference standards.
2) New standard numbers are quoted in 3.1 and 4.2. 3) Slightly added to the content of 3.3.
This standard is recommended to replace JB4380-87 from the date of implementation. This standard is proposed and centralized by the National Forging Standardization Technical Committee. The unit responsible for drafting this standard: West Instrument Group Corporation. The main drafters of this standard: Zhao Xinhuai and Yang Tongxin. 133
1 Scope
Mechanical Industry Standard of the People's Republic of China
General Technical Conditions
Metal Cold Stamping Parts
General specifications of shect metal stamping partsJB/T 4378.2: 1999
Replaces JB438087
This standard specifies the general technical conditions for metal cold stamping parts in terms of raw materials, shape and size, surface quality, heat treatment, inspection rules, packaging, etc.
This standard is applicable to metal cold stamping parts with sheet thickness greater than 0.1mm produced by cold stamping method. Stamping parts of profiles and pipes can refer to this standard.
This standard does not apply to stamping parts produced by precision blanking methods. 2 Reference standards
The provisions contained in the following standards constitute provisions of this standard by being quoted in this standard. All versions shown are valid at the time of publication. All standards are subject to revision and parties using this standard should explore the possibility of using the latest version of the standard listed below. GB/T 710--1991
GB/T 716---1991
GB/T 2517---1981
High-quality carbon structural steel hot-rolled thin steel plates and steel strips Carbon structural steel cold-rolled steel strip
Hot-rolled steel plates and strips for general structures
GB/T 2521--1996
Cold-rolled grain-oriented, non-oriented magnetic steel Tape (piece) G13/T 2828--1987
GB/T 2829-1987
Batch-by-batch inspection and counting sampling procedures and sampling tables (applicable to inspection of continuous batches) Periodic inspection and counting sampling procedures and Sampling table (suitable for inspection of production process stability) GB/T15055---1994
Dimensional limit deviation of stamping parts without tolerances
GB/T16743-1997 Blanking clearance
JB/T 4129---1999
Burr height of stamping parts
JB/T 4378. 1-1999
Structural elements of metal cold stamping parts
9 stamping and shearing Limit deviation of blanking without tolerance dimensions JB/T 4381--1999
3 Technical requirements
3.1 Raw materials
3.1.1 The raw materials used for stamping parts must comply with GB/T710 .GB/T716, GB/T2517, GB/T2521 and other relevant metal material standards, and comply with the supply status of materials or other requirements. 3.1.2 The raw materials for stamping parts should have a quality certificate, which guarantees that the materials meet the specified technical requirements. When there is no quality certificate or other reasons, the stamping parts manufacturer can select raw materials for re-inspection as needed. The main items and contents of re-inspection: 3.1.2.1 Appearance inspection: Inspect material surface defects, stains, outer dimensions, shape and thickness, and surface roughness. 3.1.2.2 Chemical analysis and metallographic inspection: analyze the content of chemical elements in the material; determine the grain size level and uniformity of the material; evaluate the level of free cementite, banded structure and non-metallic inclusions in the material; check the shrinkage of the material. Defects such as holes and looseness. 3.1.2.3 Mechanical property inspection: Test the tensile strength, yield strength, yield ratio ./h, elongation, area shrinkage and Rockwell hardness HRB, etc.
National Machinery Industry Bureau 1999-06- 24 Approved 134bzxZ.net
2000.0701 Implementation
JB/T 4378. 2.--- 1999
3.1.2.4 Forming performance test: conduct bending test and cupping test on the material to measure the material The work hardening index\value and plastic strain ratio value etc. Regarding the test method of steel plate formability, it can be carried out according to the provisions of thin steel plate formability and test methods. 3.1.2.5 Determination of other performance requirements: Determination of electromagnetic properties of materials and adhesion ability to plating and coatings, etc. 3.1.3 Material requirements for various types of stamping parts: In general, the requirements for material mechanical properties of stamping parts with different structural types are shown in Table 1. For stamping parts with complex deformation processes, there are more requirements for materials. For example, the work hardening index\value and plastic strain ratio? values ??and lug parameter value requirements, etc.
Table 1
Stamping parts categories
Blanking parts
Use the fillet radius (r>21) to make a simple bend of 90\ perpendicular to the rolling direction of the plate Oil (for material thickness)
Shallow drawing and forming
Use the fillet radius (20.5) to make a 180° bend perpendicular to the auxiliary rolling direction of the sheet or 90° parallel to the rolling direction Bending and deep drawing
180° bending and deep drawing in any direction with a fillet radius (0.52)
3.2 Shape and size
Material requirements for general stamping parts||tt ||Maximum tensile strength,
N/mm2
650
500
430
380
340
The shape and size of stamping parts must comply with the requirements of stamping part drawings and technical documents. Elongation
%
1
4-14
13--27
24~36
33-~4.5| |tt||The shape and size of stamping parts should pay attention to process limitations, and the design guidelines must follow JI3/T4378.1. The shape and dimensional tolerances of stamping parts must comply with the requirements of JB3/T4381 and GB/T15055. 3.3 Surface quality
Hardness HRB
847-95
7585
64 -~74
52~64
18~~52
Except for the punching surface, the surface condition of the stamping parts must be consistent with the sheet material used. Slight accompanying lines and small surface unevenness are allowed during the bending and drawing forming processes. Requirements for surface treatment of stamping parts, such as rust removal, pickling, oil removal, phosphating, painting, oxidation, metal plating, etc. This should be stated in the technical documentation.
3.4 ??Burrs
Stamping parts that have been sheared or punched generally have burrs. The allowable height of burrs is in accordance with JB/T4129. If the nest is not allowed to have burrs, the neck shall specify additional processes to be used.
3.5 Punching surface
The condition of the punching surface is generally not specified. According to the different requirements of the blanking parts, select a reasonable blanking gap value according to GB/T16743. When it is necessary to reduce the sag and inclination of the punching surface, eliminate tearing and improve the smoothness, it must be stipulated in the technical documents and the corresponding materials, heat treatment and fine blanking methods must be used to solve the problem. 3.6 Heat treatment and supply status
Stamping parts are generally not heat treated after stamping, forming and welding. In special circumstances, if it is required to eliminate cold work hardening, reduce internal stress or achieve certain mechanical properties, the heat treatment supply status must be specified, such as stress relief, normalizing, quenching and tempering, etc. When specifying the supply status of stamping parts, it should be noted that due to the cold work hardening of the material during stamping, the strength of the stamping parts may exceed the strength limit of the raw material, which is important for the subsequent processing or use of the stamping parts. 4 Inspection Rules
4.1 Inspection Category Period
The beauty and scope of the inspection depend on the requirements for stamping parts during subsequent processing and use, produced in Shanxi! Quality inspection department! 135
Conduct inspection according to stamping parts drawings and technical documents. 4.1.1 General inspection
JB/T 4378.2—1999
-General inspection refers to the appearance inspection and accuracy inspection of stamping parts according to the regulations of stamping parts drawings and technical documents. Appearance inspection is Rely on hand touch, visual inspection, light reflection, and light projection to inspect the appearance quality of stamped parts. Accuracy inspection uses inspection tools, clamps, measuring tools, and inspection tools to inspect the size, shape, and position accuracy of stamped parts. General inspection can be carried out according to the requirements of technical documents or using standard samples as the basis for comparison and judgment. 4.1.2Supplementary inspection
Supplementary inspection refers to inspections other than general inspection, which includes hardness inspection, magnetic crack inspection, fluorescent inspection, X-ray inspection, electrical probe inspection, ultrasonic inspection, etc. The type and scope of such inspections need to be specifically agreed upon by both parties. 4.2 Acceptance method
Since stamping parts are produced in batches, full inspection or random inspection can be carried out as needed. Sampling inspection can conduct batch-by-batch inspection of stamping parts and periodic inspection of the stability of the production process. The method of random inspection can be in accordance with the provisions of GB/T2828 and GB/T2829. 5 Marking, packaging, transportation
5.1 Stamping parts are generally not marked. Under special circumstances, the supplier and the buyer can agree on the marking. 5.2 The supply of stamped parts is allowed to deviate from the order quantity, and the allowable value shall be agreed upon by both parties. 5.3 Each batch of stamped parts shall be supplied with a certificate of conformity, the main contents of which are: a) product model, stamped part part number, and material grade: b) Name and quantity of stamped parts:
c) Conclusion of supplementary inspection on special requirements: d) Quality inspection mark.
5.4 The rust prevention, packaging, transportation methods and requirements of stamping parts shall be agreed in the order agreement. 136
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