QC/T 1250-2025 Heavy duty hose clamps ofelastic compression type for automobile English, Anglais, Englisch, Inglés, えいご
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ICS
T
Professional Standard of the People's Republic of China
QC/T 1250-2025
Heavy duty hose clamps of elastic compression type for automobile
汽车用弹性缩紧型强力软管夹箍
(English Translation)
Issue date: 2025-12-17 Implementation date: 2026-07-01
Issued by the Ministry of Industry and Information Technology of the People's Republic of China
Contents
Foreword
1 Scope
2 Normative References
3 Terms and Definitions
4 Type Dimensions
5 Technical Requirements
6 Test Methods
7 Clamp Assembly Torque
8 Quality Management and Document Archiving
Automotive Elastic Tension Type Heavy-Duty Hose Clamps
1 Scope
This document specifies the type dimensions, technical requirements, and test methods for elastic tension type heavy-duty hose clamps (hereinafter referred to as "clamps") for automotive use.
This document applies to sealing clamps for connecting hoses and rigid pipes used for transmitting gases or liquids.
2 Normative References
The contents of the following documents constitute essential provisions of this document through normative reference. For dated references, only the edition corresponding to the date applies. For undated references, the latest edition (including all amendments) applies.
GB/T 90.1 Fasteners — Inspection and Acceptance
GB/T 90.2 Fasteners — Marking and Packaging
GB/T 1222 Spring Steels
GB/T 1800.2 Geometrical Product Specifications (GPS) — Limits and Fits — Part 2: Tables of Standard Tolerance Grades and Limit Deviations for Holes and Shafts
GB/T 3098.1 Mechanical Properties of Fasteners — Bolts, Screws, and Studs
GB/T 3280 Stainless Steel Cold-Rolled Sheets and Strips
GB/T 5267.4 Fasteners — Coatings — Corrosion-Resistant Stainless Steel Passivation Treatment
GB/T 5789 Hexagon Flange Bolts — Large Series
GB/T 6478 Technical Specifications for Cold Heading Steels
GB/T 10125 Corrosion Tests in Artificial Atmospheres — Salt Spray Tests
QC/T 326 Product Numbering Rules for Automotive Fasteners
QC/T 625 Coatings and Chemical Treatment Layers for Automotive Use
3 Terms and Definitions
The following terms and definitions apply to this document.
3.1 PVT test (Pressure, Vibration, and Temperature Test)
A test for evaluating the sealing capability of hose connection systems or individual component connections using a pressure, vibration, and temperature (PVT) test apparatus.
4 Type Dimensions
The type dimensions and specifications of the clamps shall meet the requirements of Figure 1 and Table 1.
5 Technical Requirements
Technical requirements shall comply with the provisions of Table 2.
Table 2 Technical Requirements
6 Test Methods
6.1 Dimensions
The clamping range shall be inspected by tightening on a steel mandrel of the corresponding size. The mandrel tolerance shall be h14, according to GB/T 1800.2. Other dimensions shall be inspected using universal gauges.
6.2 Materials
Materials shall comply with Table 2. Before product testing, the supplier shall provide a third-party inspection report, or the verification method shall be negotiated between the supplier and the purchaser.
6.3 Corrosion Resistance
Clamps shall undergo neutral salt spray testing according to GB/T 10125. The corrosion resistance time shall be as specified in Table 2.
6.4 Torque Tests
6.4.1 Test Conditions
New clamps shall be used for each test item. Repair and supplementary lubrication are not allowed.
The error of the torque wrench shall not exceed ±3%.
6.4.2 Proof Torque Test
Fit the clamp onto a steel mandrel corresponding to the minimum clamping range of the respective specification. Tighten the drive screw smoothly to the proof torque specified in Table 2, hold for 15 seconds, then loosen the drive screw. Inspect the clamp; it shall not show yielding deformation. The clamp shall be reusable.
6.4.3 Repeat Torque Test
Fit the clamp onto a steel mandrel corresponding to the minimum clamping range of the respective specification. Tighten the drive screw smoothly to the repeat torque specified in Table 2. Repeat this 15 times, then loosen the drive screw. Inspect the clamp; all components shall show no plastic deformation. The clamp shall be reusable.
6.4.4 Destructive Torque Test
Fit the clamp onto a steel mandrel corresponding to the minimum clamping range of the respective specification. Tighten the drive screw smoothly to the destructive torque specified in Table 2, hold for 15 seconds, then loosen the drive screw. Inspect the clamp; there shall be no weld fracture or component failure.
6.5 PVT Test
The PVT test is conducted under specified temperature and pressure and has two test procedures:
— With vibration and coolant flow procedure;
— Without vibration and coolant flow procedure.
The specific test procedure shall be determined through negotiation between the supplier and the purchaser.
7 Clamp Assembly Torque
The assembly torque shall be determined based on the sealing medium, hose material, and operating conditions, or determined through PVT testing, but shall not exceed the repeat torque specified in Table 2.
8 Product Numbering
The numbering rules for clamp products shall follow the provisions of QC/T 326.
