How does the spring device increase the hardness? In order to increase the hardness, the torsion bar spring must be sufficiently heated before quenching. The high-strength torsion bar spring should be heated in a controlled atmosphere furnace, in a neutral salt bath furnace or by electric heating to reduce pitting, spalling and surface decarburization. After removing the torsion bar spring from the quenching medium, put it in immediately Tempering furnace to avoid quenching cracks. If the heating temperature is too high, not only oxidation and decarburization will occur, but also overheating and burning defects such as various eutectic structures will occur.
In order not to straighten the torsion bar after quenching, heating, quenching and spin quenching are often used in a vertical suspension state.
In order to prevent decarburization and the influence of retained austenite or martensite structure on fatigue life, regular inspections should be performed to control these defects.
In order to prevent cracks in quenching, it is necessary to strictly control the quenching heating temperature, cooling rate and time; control the performance of parts and material impurities.