Introduction to Soft Magnetic Alloy 4J42

4J42 alloy is an Fe-Ni system constant expansion alloy with a thermal expansion coefficient that matches hard glass, soft glass, and ceramics, enabling the formation of hermetic packaging shells through glass-to-metal sealing processes. It is relatively close to the thermal expansion coefficients of commonly used circuit substrates such as Al2O3, BeO, and AlN; it possesses excellent magnetic and electrical properties; and it offers good machinability, coating, and welding performance. Compared to 4J29 alloy, it does not contain more expensive precious metals, giving it a better cost advantage, making it one of the commonly used materials for metal packaging shells in microelectronic products.

4J42 Invar alloy belongs to the category of constant expansion alloys, with a linear expansion coefficient similar to that of soft glass and ceramics within a certain temperature range. Due to the absence of scarce elements, it is relatively inexpensive and has gradually replaced Kovar alloy, widely used in glass sealing for electro-vacuum components such as transmitting tubes, oscillator tubes, ignition tubes, magnetrons, electron tubes, transistors, sealed plugs, relays, lead-out wires for integrated circuits, chassis, shells, and brackets.

Chemical Composition of Soft Magnetic Alloy 4J42

Hermetic Performance of Soft Magnetic Alloy 4J42 Packaging Shells

Using Nd:YAG pulsed laser welding for 4J42 alloy packaging shells, and controlling process parameters that affect sealing, such as laser output power, welding speed, and surface treatment state of the test piece, can successfully achieve hermetic packaging of the shell.

Hot Working Process of Soft Magnetic Alloy 4J42 Wire Blanks

The production of 4J42 expansion alloy wire blanks uses rolling instead of forging and high-speed wire rod rolling technology with large coil weights to replace traditional horizontal rolling mill technology, optimizing the hot working process of wire blanks and achieving the following results:

The physical and organizational properties of the product fully meet technical requirements, demonstrating that the optimized process is feasible.

Product quality is comprehensively improved, including surface quality and dimensional accuracy.

The process flow is shortened, the production cycle is reduced, and productivity is increased.

Product yield is improved, energy consumption is reduced, production costs are significantly lowered, economic benefits are very evident, and market competitiveness of the product is enhanced. The above is an introduction to the material, properties, and processes of soft magnetic alloy 4J42.

Various specifications of plates, bars, strips, wires, discs, ring blanks, and ring forgings can be supplied. Bars are supplied in as-forged or as-rolled condition, with surface ground or turned; discs and ring blanks are supplied in as-forged condition; rings are supplied in solution-treated condition; plates are supplied after solution treatment, alkali-acid pickling, straightening, and edge trimming; strips are delivered after cold rolling, solution treatment, and descaling; wires are delivered in solution-treated and pickled coil or straight form, or in solution-treated straight fine-ground condition.