The melting point of Tungsteng electrode is about 3400 celsius degree. The arc temperature in TIG welding is about 6000 degree celsius. So, Why does not Tungsteng electrode in TIG welding melt during welding?
Welding is a process with an uneven temperature distribution: heat is supplied from the arc side and heat is dissipated from the component and electrode side. This creates temperature gradients that depend on the thermal conductivity of the component and the electrode. The higher the thermal conductivity of the material, the more energy is required to melt it. At the same time, tungsten has a very high melting temperature and a very high thermal conductivity, which is why it cannot be melted by an arc (the temperature at the tip of the electrode remains below the melting point for all arc parameters).
You can also observe the same effect of good heat dissipation from the side of the component when you are welding copper: despite the relatively low melting temperature of copper, you need more energy for welding compared to carbon steel, because copper removes heat from the welding zone 10 times better.
By the way, tungsten electrode would melt, albeit slowly, this is why in GTAW process, we use DCEN to reduce the "heat" to the tungsten electrode. If you use DCEP, the electrode tip would start melting.