Overview
ISO 7662:1988 is an international standard developed by the International Organization for Standardization (ISO) that specifies a precise method for determining the abrasion resistance of the lining in rubber and plastic hoses. This standard is critical for evaluating how hose linings perform under abrasive conditions such as grit blasting, shot blasting, and similar industrial operations. It applies to hoses with an internal bore diameter ranging from 20 to 50 mm. By providing a consistent test method, ISO 7662 allows manufacturers and users to compare the abrasion resistance of different hose materials and constructions accurately.
Key Topics
- Test Method: The standard defines a procedure where a specific quantity of metallic grit (0.7 to 0.9 mm particle size, Hardness Rockwell 58-60 HRC) is passed through the hose lining under controlled conditions to simulate abrasive wear.
- Test Setup: Utilizes an abrasive blasting enclosure containing 25 kg of grit circulated continuously during the test, and an ejector fitted with a metal-hard blasting nozzle that directs grit through the lining.
- Sample Preparation: Test specimens are hose sections 1000 mm long, weighed before and after testing with 0.1 g accuracy.
- Operating Conditions:
- Air pressure regulated at 250 kPa ± 25 kPa
- Grit flow rate of 42 g/s ± 2 g/s
- Test duration of 400 minutes ± 1 minute
- Result Calculation: Abrasion loss is quantified as the volume loss of the hose lining, derived from the weight difference before and after the test considering the material density.
- Reporting: Comprehensive test reports must include hose description, grit type, flow rate, test duration, and recorded volume loss of the lining.
Applications
ISO 7662:1988 serves a vital role in industries where hoses undergo severe abrasive wear during use. Typical applications include:
- Industrial Abrasive Conveyance: Hoses that transport abrasive media like grit and shot for surface preparation.
- Manufacturing and Construction: Assessing hose durability in sandblasting and grit blasting operations to optimize hose material selection and design.
- Quality Control and Product Development: Comparing abrasion resistance of new hose lining materials or compounds to ensure product longevity in harsh environments.
- Procurement Specifications: Providing objective test data to support the selection of hoses based on abrasion resistance performance.
- Maintenance and Safety: Preventing premature hose failure that can cause operational downtime or safety hazards caused by worn-out hose linings.
Related Standards
To complement ISO 7662, other related ISO and industry standards may be consulted for a complete understanding of hose performance and safety:
- ISO 8330 - Rubber and plastics hoses and hose assemblies - Vocabulary: Defines terms related to hoses and their components, essential for clear communication.
- ISO 4649 - Rubber- or plastics-covered abrasive belts - Determination of abrasion resistance: Focuses on abrasion testing of flexible rubber/plastic surfaces.
- ISO 18752 - Rubber and plastics hoses and hose assemblies - Hydraulic hoses: Specifies requirements and tests relevant for hydraulic hose durability.
- ASTM D3953 - Standard Test Method for Abrasion Resistance of Rubber: Another commonly used abrasion testing procedure in the rubber industry.
- EN 2386 - Rubber and plastic hoses - General specifications: Provides a framework for hose properties and testing methods.
Implementing ISO 7662:1988 enhances the reliability and durability of hoses in abrasive environments by ensuring that hose linings meet rigorous abrasion resistance criteria. This contributes not only to product quality assurance but also to operational safety and cost-efficiency in abrasive handling applications.