Mineral insulated (MI) heating cable

Mineral insulated heating cable is known for its exceptional durability and mechanical strength.

Mineral insulated heating cable is known for its exceptional durability and mechanical strength. It consists of a high-resistance conducting cable in a metal sheath. A magnesium oxide (mineral)  layer provides excellent insulation. It is the heating cable of choice for applications where the required  temperature and power output go beyond the specifications of self-regulating or constant-wattage cables.

Using heating cables

Mineral insulated heating cable is the preferred choice where high temperatures and a large power output are needed to maintain or generate process temperatures. An advantage of these heating cables is their constant power output independent of (environmental) temperature changes, up to 1000°C. Due to the variety of options for sheath material, they are suited for both hazardous and non hazardous applications. Furthermore, the range of conductor resistances allows precision adjustment to produce the exact heat required in any given application. Examples of industries that Kamet has supplied MI heating cable for include:

Specifications and physical properties of mineral insulated heating cable

MI heating cable is made by a multiple pass drawing action. The mineral insulation is provided by a highly compacted magnesium oxide layer, a non-aging and non-combustible material.

MI cable kamet

Kamet is focused on the supply of single conductor mineral insulated heating cables. Our products are offered in partnership with Okazaki, the world’s largest MI heating cable manufacturer. Some general characteristics for these cables include:

Temperature:

  • Up to 1000°C (maximum exposure)
  • Up to 800°C (maximum temperature maintenance)

Power:

  • 750V (maximum working voltage)
  • 300W/m (maximum power output)

There are many variables which make it possible to choose a mineral insulated heating cable that is a perfect match for your application. For example, we stock a range of varieties in length, diameter, resistance and material (conductor and/or sheath).  A detailed overview of specifications for our heating cable stock can be found here.

Properties of sheath materials that can be used for mineral insulated heating cable:

 Inconel 600:
Nickel-chromium alloy
Alloy 825:
Nickel-iron-chromium alloy
Stainless steel alloys
Temperature rangeCryogenic to 1000°C Cryogenic to 500°CCryogenic to 800°C
Melting point1354°C – 1413 °C1370°C – 1400°C1400°C – 1455°C
General properties– Non-magneticexcellent mechanical properties
– high strength combined with good workability
– easy to weldcan be hot and cold formed
Cost-effective material: durable and long-lasting even at  high temperature. Molybdenum contributes to exceptional hardness.There are various  alloys offering different specific characteristics/benefits.

304 Stainless Steel has lower carbon to minimize carbide precipitation and is used in high-temperature applications
316 stainless steel is most suited for welding  and architectural applications.   321 has excellent corrosion resistance up to 800°C
Corrosion resistanceHigh nickel content gives good  resistance to
– reducing environments
– chloride-ion stress-corrosion cracking
– alkaline solutions.  

The chromium provides resistance to sulfur compounds and oxidizing environments.
Relatively unaffected by most neutral and alkaline salt solutions. Resistant to steam and mixtures of steam, air and carbon dioxide
Designed to offer excellent all-round corrosion resistance for most applications.  

The nickel, in conjunction with the molybdenum and copper gives outstanding resistance to reducing environments such as those containing sulfuric and phosphoric acids. Molybdenum also aids resistance to pitting and crevice corrosion Chromium content confers resistance to a variety of oxidizing substances such as nitric acid, nitrates and oxidizing  
Stainless steel offers high corrosion resistance properties against a wide range of organic acids and alkalis.    
LimitationsNot suited to reducing atmospheres strong oxidizing solutions like hot, concentrated nitric acid, 600 has poor resistanceTemperatures above 500°C can lead to microstructural changes that decrease strength and ductility.Not all alloys are easy to weld. Is more expensive than other alloys.
Application examplesChemical and food processing, heat treating, phenol condensers, soap manufactureChemical processing, pollution control, oil and gas industry, acid production, nuclear power, and handling of radioactive wastes.Automotive, aerospace and construction industries.

Kamet is also specialized in customized heating cables. To this end we have a close working relationship with ARi Industries using their AerObiax® (two conductors) and AerOcoax® (single conductor) heating cable range. ARi industries are leading innovators in mineral insulated heating providing bespoke solutions in challenging environments (such as for NASA).

Please reach out to us for your specific heating needs as well as for any general enquiries you may have. Our in-house experts will be pleased to advise you. 


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