What problems may occur during the heat treatment of tungsten discharge needle

In the field of EDM, the heat treatment process of tungsten needles is a key link to ensure their performance and service life. First of all, the oxidation problem is the main challenge faced by discharge tungsten needles in high temperature environments. Tungsten materials are very easy to react with oxygen in the air under high temperature conditions to form an oxide layer, which not only affects the appearance quality of the tungsten needle, but more importantly, significantly reduces its conductivity, thereby affecting the stability and efficiency of EDM. In order to effectively deal with this problem, it is recommended to strictly surface treat the tungsten needle before heat treatment. Antioxidants can be applied or inert gas can be used for heating to reduce direct contact between oxygen and tungsten materials, thereby effectively controlling the occurrence of oxidation.

Secondly, deformation is also an important problem in the heat treatment process of discharge tungsten needles. Under high temperature conditions, tungsten materials may undergo plastic deformation, resulting in changes in the shape of the tungsten needle, which in turn affects its processing accuracy. To this end, precision fixtures should be used for fixation during the heat treatment process, or prestressed loading technology should be applied to ensure that the tungsten needle maintains its original shape during heating and cooling. In addition, the reasonable selection of heat treatment process parameters, such as heating rate, holding time and cooling rate, is also crucial to controlling deformation.

Quenching cracks are a problem that cannot be ignored in the heat treatment of discharge tungsten needles. During the rapid cooling process, the sharp increase in internal stress may cause cracks in the tungsten needle, which will seriously affect its service life. In order to effectively avoid the occurrence of quenching cracks, it is necessary to reasonably select the quenching medium, such as brine or oil, and strictly control the quenching speed to reduce the accumulation of internal stress. At the same time, pretreatment steps before heat treatment, such as annealing or normalizing, can also help reduce the quenching sensitivity of the material, thereby effectively reducing the probability of crack formation.

In addition, tempering brittleness is also a factor that needs to be focused on during the heat treatment of discharge tungsten needles. During the tempering stage, if the temperature is not properly controlled, the tungsten needle may become brittle, thereby reducing its fracture resistance. Therefore, strictly controlling the tempering temperature and ensuring that the tungsten needle is tempered within a suitable temperature range is a key measure to prevent tempering brittleness. At the same time, multiple tempering treatments can also help eliminate residual stress and improve the toughness and stability of the tungsten needle.