Electric heater cartridge is a piece of equipment, made of MgO powder or MgO tube, ceramic cap, resistance wire(NiCr2080),High temperature leads, seamless stainless steel sheath(304,321,316,800,840). Usually in tube form,that is used in heating applications.by way of insertion into metal blocks via a series of drilled holes.

Cartridge heaters are manufactured in two basic forms - high density and low density. High density cartridge heaters are used to heat plastic injection moulds, dies, platens and so forth, whereas low density cartridge heaters are more suitable for packing machinery, heat sealing, labelling machines and hot stamping applications.

Cartridge Heater for Electric furnace tube heater
Resistance heating wire material	Cr20Ni80
Tube material	SS304,SS316,SS310S,SS321,INCOLOY 800,INCOLOY 840
Tube diameter	3-30mm
Diameter tolerance	-0.02~0.2mm (as your request)
Tube length	15-3000mm
Length tolerance	±1mm
Max. Temperature	800℃
Wattage tolerance	-10%~5%
Voltages	12V/24V/36V/48V/110V/220V/230V/380V/415V/440V
Standard cold zone	5-10mm
Insulation resistance (cold)	≥500MΩ
Max. leakage current	≤0.5mA
Thermocouple	Type J , Type K ,Type E