NOTE: Iron tip do not work continuously high temperature, high temperature work is easy to damage the tip!    
Ordinary solder melting point is 183°C, The melting point of  solder is 227℃, usually the welding temperature is 300-380°C, 380°C is the temperature of the dividing line, higher than 380°C, iron head oxidation and loss is extremely fast, seriously affect the heating core life The Higher than 380°C temperature display will be beating, the higher the temperature, the greater the beating!Recommended in the 300-380°C for welding work, most of the work can be carried out, the temperature beating is normal, does not affect the use!   
If can use low temperature, then do not high temperature: T12 is constant temperature control, the general recommended working temperature control between 300 ℃ ~ 380 ℃, higher than 380 ℃ damage the coating of solder tip and cut down the PTC life!