4J28 Pins

4J28 is a 4J28 fine alloy with abnormal thermal expansion and cold contraction function, also known as 42s expansion alloy, which is widely used in the electronics industry, fine tools, fine instruments and cryogenics engineering. – If metals and alloys expand after heating, the expansion rate increases linearly, and the temperature increases, but the temperature of the bending point of the bending point on the thermal expansion curve of some alloys is much smaller than the normal thermal expansion coefficient of the bending point. 4j28 expansion alloy is divided into fixed expansion alloy and low expansion alloy, the latter is also known as sealing alloy.

Chemical Domposition

Mark	C	P	S	Mn	Si	Cr	Ni	Fe	Other
4J28	≤0.12	≤0.02	≤0.02	≤1.00	≤0.90	27.0~29.0	≤0.50	balance	≤0.02

 

application

(1) Components of fine instruments and optical instruments, such as fine balance arms, standard parts, swing rods, balance wheels, external compensation of clocks, etc.;

(2) Length scale. Geodetic baseline;

(3) various resonators, microwave communication waveguides, standard frequency generators, etc.;

(4) Regulating the blades and support rods of capacitors;

(5) liquid natural gas, liquid hydrogen, liquid oxygen and other storage tanks and transport pipelines;

(6) Passive layer of thermal bimetal sheet;

(7) the image of a high-resolution cathode ray tube (picture tube);

(8) composite material mold for aerospace industry;

(9) For advanced high-tech products such as satellites, lasers, and ring laser gyroscopes.

Performance

Thermal expansion alloys have a normal metal structure and lattice, and a large number of non-metallic atoms are included in them, so they have a large linear expansion coefficient in a certain temperature range. The physical properties of the thermal expansion alloy are linear expansion, that is, the length increases linearly with the increase of temperature. However, due to the temperature limit of expansion, the thermal expansion alloy can work normally within a certain temperature range.