ASTM D471 and Hydrocarbon Oils: IRM 902, IRM 903, ISO 1817, Oil No. 2 & Oil No. 3 

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Overview of ASTM D471: 
ASTM D471 is the Standard Test Method for Rubber Property—Effects of Liquids. It evaluates the resistance of rubber and elastomeric materials to swelling, deterioration, or physical property changes after exposure to hydrocarbon oils or fluids.

Application: 
Widely used in automotive, cable manufacturing, and industrial applications to ensure material compatibility.

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Reference Oils: 
ASTM D471 and ISO 1817 include specific hydrocarbon oils for testing: 

Oil Name	Hydrocarbon Composition	Purpose
IRM 902 (Oil No. 2)	Medium naphthenic, moderate aromatic	Industrial lubricants, moderate exposure
IRM 903 (Oil No. 3)	High aromatic, aggressive	Fuels, solvents, high-stress applications
ISO 1817 Oil No. 2	Equivalent to IRM 902	Moderate hydrocarbon exposure
ISO 1817 Oil No. 3	Equivalent to IRM 903	High aromatic, aggressive exposure

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Test Procedure Under ASTM D471 / ISO 1817: 

• Step 1: Prepare test samples (rubber or elastomer strips). 
  
• Step 2: Fully immerse samples in oils (e.g., IRM 902 or IRM 903) at specified temperatures (e.g., 70°C to 150°C). 
  
• Step 3: Measure changes in: 
      - Volume Swell (%) 
      - Mass Change (%) 
      - Hardness (Shore A) 
      - Tensile Properties (strength, elongation) 
  

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Hydrocarbon Composition of Oils: 

• IRM 902 Oil: 
      - Aromatic hydrocarbons: ~10-20% 
      - Naphthenic hydrocarbons: ~50-60% 
      - Paraffinic hydrocarbons: ~20-30% 
  
  
• IRM 903 Oil: 
      - Aromatic hydrocarbons: ~30-45% 
      - Naphthenic hydrocarbons: ~30-40% 
      - Paraffinic hydrocarbons: ~20-25% 
  

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Example in Cable Manufacturing: 
For testing cable sheaths or insulation: 
- Samples are immersed in IRM 903 for 72 hours at 100°C. 
- Cables are inspected for swelling, cracking, or strength loss. 

Result Analysis: 
- Minimal swelling = High resistance = Suitable for critical applications. 
- Excessive swelling or cracking = Material incompatibility.

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Significance of the Test: 
Ensures materials used in automotive cables, power cables, and industrial systems maintain their: 

• Mechanical integrity 
• Resistance to oils, fuels, and lubricants 
• Long-term performance and reliability 

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