Alloy 42, commonly known as Invar 42, is a nickel-iron alloy that exhibits a very low coefficient of thermal expansion, slightly higher than Alloy 36 but still notable for precision applications. Alloy 42 is recognized under various designations and standards, including NILO 42, UNS K94100, DIN 1.3917, FE-NI42, 42N, W.NR. 1.3917, and DILATON 42. These designations underscore its international acceptance and adherence to diverse industry specifications.

The alloy is composed of about 42% nickel, with the balance being predominantly iron. This combination delivers a low thermal expansion rate, making it highly suitable for applications where maintaining dimensional integrity is critical despite temperature changes.

Alloy 42 Sheet | Plate

Alloy 42 sheets and plates are available in various thicknesses and dimensions. They are designed to provide high dimensional stability and flatness, making them essential for precision manufacturing. These forms are commonly used in high-tech sectors such as aerospace, telecommunications, and precision instrumentation, where maintaining exact dimensions is essential.

Alloy 42 Round Bar | Rod

Alloy 42 round bars and rods come in a range of diameters and lengths, suitable for turning and milling into custom parts. These components are vital for applications such as mechanical linkages, structural components, and various fittings that must resist thermal distortion. Their stability under temperature changes makes them ideal for precision-engineered parts.

Alloy 42 Strip | Coil

Available in flexible strips and coils, Alloy 42 is utilized for applications that require materials to be bent, formed, or used continuously. These products are particularly valuable in the manufacture of springs, connectors, and other components where both flexibility and dimensional stability are required. They find application in automotive, electronics, and high-precision machinery.

Alloy 42 Applications

• Glass to metal seals for a wide variety of electronic tubes, hermetic packages, automotive and industrial lamps.

Alloy 42 Properties

• Coefficient of Thermal Expansion: Approximately 1.5 x 10^-6 /°C, making Alloy 42 well-suited for applications requiring high precision and minimal expansion.
• Density: Around 8.1 g/cm³, which provides an optimal balance of strength and weight for various industrial applications.
• Thermal Conductivity: Approximately 12-14 W/m·K, offering moderate heat conduction while ensuring dimensional stability.
• Magnetic Properties: Generally ferromagnetic, which can be a critical consideration for applications where magnetic interference needs to be managed.
• Mechanical Properties: Alloy 42 offers good strength and ductility, engineered for maintaining dimensional precision rather than maximum mechanical strength.

Machining Alloy 42

• Cutting: Alloy 42 can be cut using conventional tools. It is important to use sharp tools and to adjust cutting speeds to avoid excessive wear and achieve smooth cuts.
• Drilling: For drilling Alloy 42, high-speed steel (HSS) drills or carbide-tipped bits are recommended. Proper lubrication and cooling are essential to prolong tool life and ensure clean, accurate holes.
• Turning: Carbide inserts are preferred for turning Alloy 42. Consistent feed rates and effective heat management are crucial to maintain dimensional accuracy during the turning process.
• Milling: Alloy 42 can be milled effectively using conventional techniques. Employ carbide end mills and cooling fluids to control heat and prevent dimensional distortions during milling.
• Grinding: Grinding Alloy 42 is ideal for achieving tight tolerances and fine surface finishes. Use suitable abrasive wheels and coolant to ensure a high-quality finish and preserve dimensional integrity.

Chemical Composition

• Nickel (Ni): Min 41%
• Carbon (C): Max 0.05%
• Manganese (Mn): Max 0.80%
• Phosphorus (P): Max 0.025%
• Sulfur (S): Max 0.025%
• Silicon (Si): Max 0.030%
• Chromium (Cr): Max 0.250%
• Aluminum (Al): Max 0.10%
• Iron (Fe): Balance