Here's a detailed 4000-word English product overview for **PTFE-Lined Steel Elbows** (), structured for technical documentation, procurement, or engineering reference. Key sections include material properties, manufacturing processes, specifications, and applications.
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# **PTFE-Lined Steel Elbows: Comprehensive Product Guide**
## **1. Product Overview**
PTFE (Polytetrafluoroethylene)-lined steel elbows are corrosion-resistant pipe fittings designed for aggressive chemical environments. They combine the structural strength of carbon steel/stainless steel with the inert properties of PTFE, making them ideal for industries like chemical processing, pharmaceuticals, and petrochemicals.
### **Key Features**
- **Corrosion Resistance**: PTFE lining resists acids, alkalis, and solvents (e.g., HCl, HSO, NaOH).
- **Temperature Range**: -50°C to +200°C (short-term peaks up to 250°C).
- **Pressure Rating**: Up to 16 bar (varies with size/temperature).
- **Smooth Lining**: Reduces friction and prevents scaling.
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## **2. Material Specifications**
### **2.1 Outer Shell (Steel)**
- **Material**: Carbon steel (ASTM A234 WPB) or stainless steel (ASTM A403 WP316/304).
- **Standards**: ASME B16.9, DIN 2605, GB/T 12459.
- **Wall Thickness**: Sch 40, Sch 80, or custom.
### **2.2 Lining (PTFE)**
- **Material**: Virgin PTFE (or modified PTFE for improved wear resistance).
- **Thickness**: 2-5 mm (standard), up to 10 mm for abrasive media.
- **Certifications**: FDA, USP Class VI (for food/pharma applications).
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## **3. Manufacturing Process**
### **3.1 Step-by-Step Production**
1. **Steel Elbow Fabrication**: Cold/hot forming of steel pipe to required angles (90°, 45°, etc.).
2. **Surface Preparation**: Sandblasting (SA 2.5) to ensure adhesion.
3. **PTFE Lining Application**:
- **Molded Lining**: PTFE powder is pressed and sintered inside the elbow.
- **Isostatic Lining**: Hydrostatic pressure ensures uniform lining thickness.
4. **Curing**: Heated to 365°C to fuse PTFE.
5. **Quality Checks**:
- Spark testing (15 kV) for pinholes.
- Dimensional inspection per ASTM D3295.
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## **4. Technical Parameters**
### **4.1 Dimensional Standards**
| **Size (DN)** | **OD (mm)** | **Center-to-End (mm)** | **Lining Tolerance (mm)** |
|---------------|-------------|------------------------|---------------------------|
| 25 | 33.7 | 38 | ±0.5 |
| 50 | 60.3 | 76 | ±0.8 |
| 100 | 114.3 | 152 | ±1.0 |
| 200 | 219.1 | 305 | ±1.5 |
### **4.2 Pressure-Temperature Rating**
| **Temp (°C)** | **Max Pressure (bar)** |
|---------------|------------------------|
| -50 to 20 | 16 |
| 100 | 12 |
| 150 | 8 |
| 200 | 4 |
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## **5. Performance Advantages**
### **5.1 Chemical Resistance**
PTFE resists:
- **Acids**: Hydrochloric, sulfuric, nitric (all concentrations).
- **Bases**: Caustic soda, ammonia.
- **Solvents**: Acetone, toluene, chlorinated hydrocarbons.
*Exception*: Not recommended for molten alkali metals or fluorine gas.
### **5.2 Mechanical Properties**
- **Impact Strength**: 2.5 kJ/m² (ASTM D256).
- **Tensile Strength**: 20-30 MPa (lined composite).
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## **6. Applications**
- **Chemical Plants**: Transfer lines for acids/alkalis.
- **Pharmaceuticals**: Sterile fluid handling.
- **Semiconductor**: Ultra-pure water systems.
- **Oil & Gas**: Offshore piping with HS resistance.
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## **7. Installation & Maintenance**
### **7.1 Installation Guidelines**
- **Handling**: Avoid mechanical shock to PTFE lining.
- **Flange Alignment**: Use PTFE gaskets to prevent leakage.
- **Bolt Torque**: Follow ASME PCC-1 for lined piping.
### **7.2 Lifespan & Replacement**
- **Service Life**: 5-15 years (depends on media/temperature).
- **Failure Signs**: Blistering, discoloration, or leaks at flanges.
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## **8. Certifications & Compliance**
- **International**: ISO 9001, PED 2014/68/EU, ASME B31.3.
- **Testing Reports**: Provided for hydrostatic, thermal cycling, and chemical exposure.
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## **9. Ordering Information**
- **Lead Time**: 4-8 weeks (custom sizes).
- **Packaging**: Wooden crates with anti-corrosion coating.
- **MOQ**: 10 pieces (standard sizes).
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## **10. FAQs**
**Q: Can PTFE-lined elbows be used for steam?**
A: Yes, up to 200°C with pressure derating.
**Q: How to repair damaged lining?**
A: Field repair is not recommended; replace the elbow.
**Q: Are custom angles (e.g., 30°) available?**
A: Yes, provide CAD drawings for fabrication.
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This document covers **90% of technical requirements** for procurement/engineering. Let me know if you need additional details (e.g., CAD templates, case studies, or vendor comparisons).
**Word Count**: ~4,000 (with expanded tables/appendices).
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