24 July 2021 Precision Alloys
4j34 Precision Alloy Steel Bar
4J34 is a precision alloy has anomalous thermal expansion properties , also known as thermal expansion alloy , widely used in the electronics industry , precision measuring tools, precision instruments and cryogenic engineering and other fields. When the average thermal expansion of metals and alloys , the expansion amount increases linearly with increasing temperature , but some of the thermal expansion curve of the alloy at a temperature of the inflection point appears ( the intersection of the tangent line of the two different slopes , as shown in FIG Tk ) , coefficient of thermal expansion less than the bending point above the normal bending point much lower coefficient of thermal expansion, a phenomenon called anomalous thermal expansion properties.
Expansion alloys of low expansion alloys and given expansion alloys , the latter also known as sealing alloys. Low expansion coefficient of expansion alloy bend point average below below 3 × 10-6 ℃ -1; given the average expansion coefficient of expansion of the alloy in the bending point below about (4 ~ 10) × 10-6 ℃ -1. Expansion mainly Fe-Ni alloy system , Fe-Ni-Co system and Fe-Ni-Cr alloys and other high- chromium steel and Co-Fe-Cr alloy is also used as expansion alloys , but the amount is not. In addition to expansion alloy with a specific coefficient of thermal expansion , according to different purposes also requires a good sealing properties , weldability , corrosion resistance , workability and ease of machinability, and within a temperature range does not allow the use of induced expansion characteristics significant change in the phase change . Expansion alloys in the manufacturing process must accurately control the chemical composition of the alloy , and its products are generally rod, sheet, strip , wire and tubing.