Petroleum Products Copper Strip Corrosion Tester (ASTM D130, ISO 2160, GB/T 5096)
The Copper Strip Corrosion Test is used to evaluate the corrosiveness of petroleum products, such as lubricating oils, hydraulic oils, fuels, and grease, on copper components. This test determines the presence of active sulfur compounds or other corrosive elements in the sample.
1. Applicable Test Standards
✅ ASTM D130 – Standard Test Method for Copper Strip Corrosion by Petroleum Products
✅ ISO 2160 – Petroleum Products – Corrosiveness to Copper
✅ GB/T 5096 – Chinese Standard Equivalent to ASTM D130
2. Copper Strip Corrosion Tester – Key Features
🔹 Test Temperature: 50°C to 150°C (common: 100°C ± 1°C for lubricants)
🔹 Test Duration: 1 – 3 hours (varies based on product type)
🔹 Bath Type: Glass or stainless steel oil bath with precise temperature control
🔹 Sample Capacity: 4–12 test tubes per batch
🔹 Rotating Sample Holder: Ensures uniform exposure of the copper strip
3. Test Procedure
Step 1: Sample Preparation
1️⃣ Clean a copper strip (12.5 × 75 × 1.5 mm, ASTM D130 Standard)
- Polish with fine sandpaper (600–1200 grit)
- Clean with n-hexane or toluene and dry
2️⃣ Prepare the Sample
- Pour 30–50 mL of the petroleum product into a test tube
- Insert the polished copper strip into the sample
Step 2: Heating & Reaction
3️⃣ Heat the sample at the specified temperature
- Fuels (Gasoline, Diesel, Kerosene): 50°C for 3 hours
- Lubricants & Hydraulic Oils: 100°C for 3 hours
- High-Temperature Applications: 150°C for 1 hour
4️⃣ Use an oil or liquid bath with ±1°C accuracy
Step 3: Copper Strip Evaluation
5️⃣ Remove and Rinse the Copper Strip
- Wash with toluene and acetone, then dry
6️⃣ Compare Against ASTM Copper Strip Corrosion Chart
- Use a standard color scale (ASTM D130 rating chart) to classify corrosion level
4. Copper Strip Corrosion Rating System (ASTM D130, ISO 2160)
| Rating | Description | Appearance | Corrosiveness |
|---|---|---|---|
| 1a | Slight Tarnish | Light Orange | Non-Corrosive ✅ |
| 1b | Slight Tarnish | Darker Orange | Non-Corrosive ✅ |
| 2a | Moderate Tarnish | Light Brown | Slightly Corrosive ⚠️ |
| 2b | Moderate Tarnish | Dark Brown | Slightly Corrosive ⚠️ |
| 3a | Moderate Corrosion | Reddish-Brown | Corrosive ❌ |
| 3b | Moderate Corrosion | Dark Brown to Black | Corrosive ❌ |
| 4a | Severe Corrosion | Black, Pitted Surface | Highly Corrosive ❌ |
| 4b | Severe Corrosion | Deep Black, Severe Pitting | Highly Corrosive ❌ |
✅ Pass Criteria: Lubricants and fuels should not exceed 1b rating after the test.
5. Example Test Results & Interpretation
| Product | Test Temperature | Test Duration | Copper Strip Rating | Pass/Fail |
|---|---|---|---|---|
| Hydraulic Oil | 100°C | 3 hours | 1a | ✅ PASS |
| Gasoline (with sulfur additive) | 50°C | 3 hours | 3a | ❌ FAIL |
| Diesel Fuel | 50°C | 3 hours | 2b | ⚠️ Borderline |
| High-Temperature Grease | 150°C | 1 hour | 1b | ✅ PASS |
✅ Lubricating oils, fuels, and greases must achieve a rating of 1a or 1b to pass.
Step-by-Step Guide for Copper Strip Corrosion Test (ASTM D130, ISO 2160, GB/T 5096)
The Copper Strip Corrosion Test evaluates the corrosiveness of petroleum products (lubricating oils, fuels, and greases) by exposing a polished copper strip to the sample at a controlled temperature and time.
1. Required Equipment & Materials
✅ Copper Strip Corrosion Tester (ASTM D130 compliant)
✅ Test Tubes (50–100 mL, heat-resistant glass)
✅ Polished Copper Strips (12.5 × 75 × 1.5 mm, ASTM D130 standard)
✅ Thermostatic Oil Bath (for precise temperature control)
✅ Standard ASTM Copper Strip Corrosion Rating Chart
✅ Reagents & Solvents:
- Sandpaper (600–1200 grit) or polishing cloth
- Toluene, n-hexane, or acetone (for cleaning)
- Gloves and tweezers (to prevent contamination)
2. Test Procedure
Step 1: Copper Strip Preparation
1️⃣ Polish the Copper Strip
- Use 600–1200 grit sandpaper to remove oxidation.
- Polish until the surface is shiny and smooth.
- Wipe with toluene or n-hexane and dry with a lint-free cloth.
- Hold with tweezers to avoid contamination.
2️⃣ Prepare the Test Sample
- Pour 30–50 mL of the petroleum product into a clean test tube.
- Insert the polished copper strip vertically into the sample.
- Ensure the strip is fully immersed and not touching the glass.
Step 2: Heating & Reaction
3️⃣ Set Up the Copper Strip Corrosion Tester
- Preheat the oil bath to the required temperature:
- Lubricating oils, hydraulic oils → 100°C (±1°C) for 3 hours
- Fuels (gasoline, diesel, kerosene) → 50°C for 3 hours
- High-temperature grease applications → 150°C for 1 hour
4️⃣ Start the Test
- Place the test tube (with the sample and copper strip) into the thermostatic oil bath.
- Set the timer based on the test standard.
- Ensure a stable and uniform temperature throughout the test.
Step 3: Copper Strip Evaluation
5️⃣ Remove the Copper Strip
- Use tweezers to carefully take out the strip after the test time.
- Rinse with toluene or acetone and gently wipe dry.
6️⃣ Compare Against the ASTM Copper Strip Corrosion Chart
- Hold the strip under consistent lighting conditions.
- Match the color and tarnish level to the ASTM D130 rating chart.
3. Copper Strip Corrosion Rating System (ASTM D130, ISO 2160)
| Rating | Description | Appearance | Corrosiveness |
|---|---|---|---|
| 1a | Slight Tarnish | Light Orange | Non-Corrosive ✅ |
| 1b | Slight Tarnish | Darker Orange | Non-Corrosive ✅ |
| 2a | Moderate Tarnish | Light Brown | Slightly Corrosive ⚠️ |
| 2b | Moderate Tarnish | Dark Brown | Slightly Corrosive ⚠️ |
| 3a | Moderate Corrosion | Reddish-Brown | Corrosive ❌ |
| 3b | Moderate Corrosion | Dark Brown to Black | Corrosive ❌ |
| 4a | Severe Corrosion | Black, Pitted Surface | Highly Corrosive ❌ |
| 4b | Severe Corrosion | Deep Black, Severe Pitting | Highly Corrosive ❌ |
✅ Pass Criteria: Lubricating oils, fuels, and greases must have a rating of 1a or 1b to be considered non-corrosive.
4. Example Test Results & Interpretation
| Sample | Test Temperature | Test Duration | Copper Strip Rating | Pass/Fail |
|---|---|---|---|---|
| Hydraulic Oil | 100°C | 3 hours | 1a | ✅ PASS |
| Gasoline (with sulfur additive) | 50°C | 3 hours | 3a | ❌ FAIL |
| Diesel Fuel | 50°C | 3 hours | 2b | ⚠️ Borderline |
| High-Temperature Grease | 150°C | 1 hour | 1b | ✅ PASS |
5. Common Causes of Test Failure & Solutions
| Issue | Possible Cause | Solution |
|---|---|---|
| Dark or Blackened Copper Strip | Presence of active sulfur compounds in oil | Use low-sulfur additives or upgrade base oil |
| Uneven Tarnish | Incomplete immersion or contamination | Ensure full immersion and clean test tube |
| Excessive Corrosion (>2b rating) | Poor formulation or metal contamination | Use high-quality corrosion inhibitors |
6. Summary of Pass/Fail Criteria
✅ Copper Strip Rating 1a or 1b = PASS (Non-Corrosive)
⚠️ Rating 2a or 2b = Borderline (May require reformulation)
❌ Rating 3a, 3b, 4a, 4b = FAIL (Corrosive, not suitable for use)