Heating treatment process of railway elastic strips
Dec 15, 2023| Railway clips are key components of railway tracks. Reasonable heat treatment process is a necessary condition for the production of standard elastic rods.
The spring bars are produced from 60Si2MnA thermally bonded tool steel. Its composition, surface carburized layer diameter does not exceed one percent, grain size ≥7, and high-purity graphite carbon content ≤1.5, which is the key to the production of spring bars. The steps are: opening → high-frequency non-contact heating → stamping molding → oil cooling → medium temperature quenching → shot peening → anti-corrosion solution. The characteristics and mechanism of railway elastic strips, the fire resistance should be HRC60.
The strength after quenching should be HRC44-48. The railway clips cannot break after 30,000 to 50,000 fatigue tests, and the residual deformation does not exceed 1.b250m. During the heat treatment process, the workpiece is placed into an induction switch (electromagnetic coil). When the induction switch reaches a certain frequency of alternating current, the surrounding electromagnetic field will change alternately. The magnetic effect of the alternating electromagnetic field current generates a closed induced electromotive force - vortex - inside the workpiece. The induced electromotive force is very uneven across the cross-section of the workpiece. The current intensity on the surface of the workpiece is very high and slowly decreases inward. This situation is called the skin effect.
The change in electromagnetic energy on the surface of a workpiece with high-density current is the energy that causes the surface temperature to rise, that is, the surface temperature remains unchanged. The higher the frequency of current flow, the greater the difference in current intensity between the surface and the interior of the workpiece, and the thinner the heating layer. After the temperature of the heating layer exceeds the zero boundary point temperature of steel, fire and heat treatment processes can be used to maintain the surface