Introduction to the properties and applications of 4J50 precision alloy

4J50 overview

4J50 alloy is an iron-nickel constant expansion alloy whose composition matches the expansion coefficient of different soft glasses and ceramics in a given temperature range by adjusting the nickel content. As the nickel content increases, the expansion coefficient and Curie point of the 4J50 alloy also increase. This alloy is widely used as a sealing structural material in the electric vacuum industry.

4J50 alloy has good constant expansion performance and corrosion resistance, and has a high Curie point.

4J50 alloy is a precision sealing material commonly used in the electric vacuum industry. It is widely used in packaging and protecting electronic devices or instruments through its specific constant expansion performance and good process performance.

Chemical Composition of 4J50 Precision Alloy

material	4J50
chemical composition	C	Mn	Si	P	S	Al	Co	Ni	Fe
chemical composition	≦0.05	≦0.8	≦0.3	≦0.02	≦0.02	≦0.1	≦1.0	49.5-50.5	margin

Heat treatment of 4J50 precision alloy

The heat treatment system of 4J50 precision alloy is as follows:

Heating temperature: place the sample in a hydrogen atmosphere, and the heating temperature is 900°C±20°C.

Heat preservation time: heat preservation at heating temperature for 1 hour to ensure that the sample reaches a uniform temperature.

Cooling rate: Cool the heat-preserved sample to below 200°C at a rate not greater than 5°C/min.

This heat treatment regime is designed to heat treat the 4J50 alloy to adjust its grain structure and improve the performance and stability of the material. Specific heat treatment processes help the alloy achieve desired properties such as mechanical properties, magnetic properties, and corrosion resistance.

Thermal properties of 4J50 precision alloys

4J50 precision alloy has good thermal properties. The following are some relevant thermal performance parameters:

Melting temperature: The melting temperature of 4J50 alloy is about 1430°C. This means that the alloy is able to maintain structural stability at high temperatures.

Thermal conductivity: The thermal conductivity of 4J50 alloy is 16.7W/(m·℃). Thermal conductivity indicates the ability of a material to conduct heat, and the high thermal conductivity of this alloy helps in the transfer and dispersion of heat.

Specific heat capacity: The specific heat capacity of 4J50 alloy is 502J/(kg·℃). Specific heat capacity is the heat absorbed or released by a unit mass of a material under temperature changes. A higher specific heat capacity means the alloy can store more heat when it absorbs or releases heat.

These thermal performance parameters make 4J50 precision alloy suitable for many high temperature environments and heat treatment applications, such as high temperature measurement equipment, thermocouples and heat sensitive components, etc.

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20～300℃	20～400℃	20～450℃
9.2～10.0	9.2～9.9	–

Physical Properties of 4J50 Precision Alloy

4J50 density ρ=8.21g/cm3

4J50 Electrical Properties Resistivity ρ=0.44μΩ·m

/10-6℃-1
20～100℃	20～200℃	20～300℃	20～350℃	20～400℃	20～450℃	20～500℃	20～600℃
9.8	9.8	9.5	9.4	9.4	9.4	9.7	10.6

Magnetic Properties of 4J50 Precision Alloy

4J50 precision alloy has certain magnetic properties and good corrosion resistance. Here are some parameters about its magnetic and chemical properties:

Curie point: The Curie point of 4J50 alloy is 500°C. When the temperature is lower than the Curie point, the alloy exhibits magnetism, and when the temperature is higher than the Curie point, the magnetism gradually disappears.

Magnetic properties: Under the magnetic field strength of 4000A/m, the residual magnetic induction of 4J50 alloy is 1.03T, and the coercive force is 10A/m. The residual magnetic induction indicates the magnetic induction that the alloy still retains after the magnetic field is removed, and the coercive force indicates how much reverse magnetic field needs to be applied to return the alloy magnetic field to zero.

Chemical properties: 4J50 alloy has good corrosion resistance in the atmosphere, fresh water and sea water. This means that the alloy is resistant to adverse factors such as oxidation, corrosion and deterioration in various environments.

To sum up, 4J50 precision alloy not only has certain magnetic properties, suitable for magnetic field applications, but also has good corrosion resistance, and can be used in various.

H/(A/m)	8	16	24	40	80
B/T	0.29	0.64	0.74	0.83	0.94
H/(A/m)	160	400	800	2000	4000
B/T	1.06	1.20	0.30	1.44	1.50

Application and use requirements of 4J50 precision alloy

4J50 precision alloy has a wide range of application fields, mainly including the following aspects:

Making precision impedance diaphragms: 4J50 alloy is widely used in the electronic field and can be used to make high-precision impedance diaphragms for sensing and control of circuits.

Wet reed and dry reed relay: Because 4J50 alloy has stable magnetic properties and low hysteresis loss, it can be used to make wet and dry reed relays for circuit switches and automatic control systems.

Precision length measurement: The unique thermal expansion characteristics of 4J50 alloy make it an ideal material for making precision length measurement devices, which can be used in the field of measurement and control.

Sealing with soft glass: 4J50 alloy has a similar thermal expansion coefficient to soft glass, so it can be used for sealing with soft glass, such as glass-to-metal sealing.

During the application process, you need to pay attention to the following requirements:

Selection of sealing materials: materials that match the expansion coefficient of 4J50 alloy should be selected to avoid problems caused by thermal stress during sealing.

Grain size control: In the heat treatment process, the grain size of 4J50 alloy needs to be controlled to ensure that the material has good deep drawing and drawing properties and stability.

Check the airtightness of the material: When using forged or rolled materials, it is necessary to strictly test the airtightness of the 4J50 alloy to ensure the quality of the product.

In general, 4J50 precision alloy has important application value in the fields of aviation, electronics, measurement and control.