The coefficient of expansion of the housing is greater than that of the glass

As it passes through a high temperature furnace under a controlled atmosphere, the housing expands, the glass melts and fills the cavities. When cooling, the glass is pressurized by the housing. This is what happens with seals on housings made of stainless steel, inconel alloys and the like.

This type of seal is very resistant to mechanical stresses and is furthermore economical to produce. This seal is widely used in the connector industry or for the manufacture of base units for sensors (pressure, temperature etc.).

Materials for the housing :

• Stainless steel (AISI 303, 304L, 316L, 321…)
  
  
• Inconel © (X750 ©, 718 ©…)
  
  
• Mild steel (XC10F…)

Materials for the pins :

• FeNi (ASTM F30, Nilo ©, N48 ©, N52 ©)
  
  
• FeNiCo (ASTM F15, Kovar © , Nilo K ©, Dilver P ©)
  
  
• FeCo ( Vacon ©)