Alloy 43ph,Low expansion 43Ph Alloy,，EFORU

### **Alloy 43PH / Low Expansion 43PH Alloy - Technical Datasheet** --- #### **1. Overview** **Alloy 43PH** is a precipitation-hardening, low thermal expansion nickel-iron-cobalt alloy that combines the unique characteristics of controlled thermal expansion with high strength achievable through heat treatment. This alloy maintains the dimensional stability typical of low expansion "Invar-type" alloys while providing significantly higher mechanical properties than conventional soft magnetic or low expansion alloys in their annealed condition. --- #### **2. Chemical Composition (Weight %)** The composition is balanced to provide both low thermal expansion and precipitation hardening capability. | Element | Content (%) | Role & Benefit | |---------|-------------|----------------| | **Nickel (Ni)** | 42.0 - 43.0 | Primary element controlling thermal expansion coefficient | | **Iron (Fe)** | Balance | Base element of the alloy | | **Cobalt (Co)** | 2.0 - 3.0 | Enhances strength and contributes to precipitation hardening | | **Titanium (Ti)** | 0.50 - 1.00 | Forms strengthening precipitates (γ' phase) during aging | | **Aluminum (Al)** | 0.30 - 0.70 | Contributes to precipitation hardening | | **Niobium (Nb)** | 0.50 - 1.00 | Forms strengthening carbides and nitrides | | **Manganese (Mn)** | ≤ 0.50 | Aids in deoxidation during melting | | **Silicon (Si)** | ≤ 0.25 | Improves fluidity and acts as a deoxidizer | | **Carbon (C)** | ≤ 0.03 | Controlled to prevent excessive carbide formation | | **Sulfur (S)** | ≤ 0.015 | Controlled impurity | | **Phosphorus (P)** | ≤ 0.015 | Controlled impurity | --- #### **3. Physical Properties** The alloy maintains low thermal expansion while offering enhanced mechanical properties. | Property | Value | |----------|-------| | **Density** | 8.15 g/cm³ (0.294 lb/in³) | | **Melting Point** | 1425-1450°C (2600-2640°F) | | **Specific Heat (20°C)** | 500 J/kg·K | | **Thermal Conductivity** | 12.5 W/m·K (at 20°C) | | **Mean Coefficient of Thermal Expansion** | **2.5 × 10⁻⁶/°C (20-100°C)**
**3.8 × 10⁻⁶/°C (20-200°C)** | | **Electrical Resistivity** | 0.85 μΩ·m | | **Modulus of Elasticity** | 155 GPa (22.5 × 10⁶ psi) | | **Curie Temperature** | ~300°C (570°F) | | **Magnetic Properties** | Ferromagnetic | --- #### **4. Mechanical Properties** Properties vary significantly with heat treatment condition. **Solution Annealed Condition:** | Property | Value | |----------|-------| | **Tensile Strength** | 620 MPa (90 ksi) | | **Yield Strength (0.2% Offset)** | 380 MPa (55 ksi) | | **Elongation** | 25% | | **Hardness** | 85 HRB | **Aged Condition (H900):** | Property | Value | |----------|-------| | **Tensile Strength** | 1240 MPa (180 ksi) | | **Yield Strength (0.2% Offset)** | 1170 MPa (170 ksi) | | **Elongation** | 12% | | **Hardness** | 38 HRC | --- #### **5. Heat Treatment** **Solution Treatment:** 980°C (1800°F) for 1 hour, rapid cool **Aging Treatments:** - H900: 480°C (900°F) for 4 hours, air cool - H1000: 510°C (950°F) for 4 hours, air cool - H1100: 595°C (1100°F) for 4 hours, air cool --- #### **6. Product Applications** **Alloy 43PH** serves critical roles in precision applications requiring both dimensional stability and high strength: - **Aerospace & Defense:** - Missile guidance system components - Spacecraft structural members - Aircraft control system linkages - **Precision Instruments:** - Laser system frames and mounts - Optical positioning stages - Metrology equipment structures - **Semiconductor Manufacturing:** - Wafer stage components - Precision fixture elements - Inspection equipment frames - **Energy Sector:** - Turbine alignment components - Power generation system linkages - **Advanced Manufacturing:** - Precision mold bases - Coordinate measuring machine components - High-stability gaging fixtures --- #### **7. International Standards** The material conforms to several international specifications: | Standard | Specification | |----------|---------------| | **ASTM** | Custom alloy (typically supplied to customer specifications) | | **AMS** | AMS xxx (Specific to customer requirements) | | **UNS** | UNS K94xxx | | **Military** | MIL-DTL-xxx | | **European** | Proprietary alloy specification | --- #### **8. Fabrication Characteristics** - **Machining:** Best machined in solution annealed condition - **Forming:** Good formability in annealed condition - **Welding:** Weldable using GTAW (TIG) with matching filler metal - **Heat Treatment:** Requires precise control of aging parameters - **Surface Treatment:** Can be passivated or plated as required --- #### **9. Summary** **Alloy 43PH** represents an advanced class of precipitation-hardening low expansion alloys that bridge the gap between conventional low expansion materials and high-strength superalloys. Its unique combination of controlled thermal expansion and high mechanical strength makes it invaluable for advanced aerospace, defense, and precision instrumentation applications where both dimensional stability and structural integrity are critical. The alloy's ability to be heat treated to various strength levels provides design flexibility while maintaining essential low expansion characteristics across a wide service temperature range.

Packing of Standard Packing: Typical bulk packaging includes palletized plastic 5 gallon/25 kg. pails, fiber and steel drums to 1 ton super sacks in full container (FCL) or truck load (T/L) quantities. Research and sample quantities and hygroscopic, oxidizing or other air sensitive materials may be packaged under argon or vacuum. Solutions are packaged in polypropylene, plastic or glass jars up to palletized 1710 gallon liquid totes Special package is available on request.