Kovar Alloy 29 (4J29)/UNS K94610/W. Nr.1.3981 ASTM F15 Bar Sheet Strip Tube

Overview

Nilo alloy 4J29, commonly referred to as Kovar alloy, is a carefully designed and optimized nickel-iron alloy. This alloy is widely acclaimed for its unique physical and chemical properties, especially in applications where the material's coefficient of linear expansion, thermal stability and corrosion resistance are strictly required.

The main components of 4J29 alloy are iron and nickel, and a certain amount of cobalt is added to achieve the required properties. Its coefficient of linear expansion is precisely adjusted to match specific types of glass and ceramic materials, such as borosilicate glass, thus ensuring excellent sealing performance over a wide temperature range. This characteristic makes 4J29 alloy ideal for the manufacture of highly reliable electronic packages and vacuum devices.

Nilo alloy 4J29 also exhibits excellent corrosion resistance, maintaining the stability of its structure and properties even in humid, salt spray or other corrosive environments. This makes it an ideal material for equipment operating in harsh conditions, such as Marine engineering, chemical processing, and aerospace applications.

Limiting Chemical Composition, %

Iron............................................................................................................................................................................................Balance.

Nickel...................................................................................................................................................................................28.50-29.50

Cobalt..................................................................................................................................................................................16.80-17.80

Molybdenum...........................................................................................................................................................................0.20 max.

Chromium...............................................................................................................................................................................0.20 max.

Copper.....................................................................................................................................................................................0.20 max.

Silicon.....................................................................................................................................................................................0.30 max.

Manganese.............................................................................................................................................................................0.50 max.

Sulphur....................................................................................................................................................................................0.02 max.

Phosphorus............................................................................................................................................................................0.02 max.

Carbon......................................................................................................................................................................................0.03 max.

Physical Constants

Mechanical Properties

Typical Mechanical Properties of Strip(Tested parallel to the direction of rolling,Material annealed 1830°F for 30 minutes, then furnaced cooled)

Magnetic Properties

Kovar alloy is magnetic at all temperatures below the Curie point. Magnetic properties will depend upon heat treatment; the lower the hardness, the higher the permeability values and lower hysteresis loss. Examples of permeability properties are shown in the following chart:

Thermal Treatments

All degreased, fabricated Kovar alloy parts should be degassed and annealed in a wet hydrogen atmosphere. Atmosphere is to be made moist by bubbling the hydrogen through water at room temperature. Care must be taken to prevent surface carbon pickup. Furnace should have a cooling chamber provided with the same atmosphere. Heating should be conducted within the 1540/2010°F temperature range. Time at temperature should be approximately two hours for lowest temperature to 20 minutes for the highest temperature. Parts should then be transferred to the cooling zone and held until below 570°F, then removed. An oxide film on the metallic part is preferred for metal-to-hard glass sealing. The best oxide film is thin and tightly adhering. The film can be produced by heating the parts to 1200/1290°F in regular ambient atmosphere for a time sufficient to form a dark gray to slight brown oxide.

Avaliable Forms

We provide you with a variety of product forms, including but not limited to

● Bar & Rod

● Pipe & Tube

● Coil & Strip

● Plate & Sheet/Circle

● Wire

● Fitting (Flange, Elbow, Tee...)

● Customize