Flex Heater Elements

Foil element choice will be determined by your heater profile. A heater profile can be determined through experimentation with standard heaters and your desired thermal needs. The heaters should be arranged at varying power levels to determine optimum temperature gradient across the entire surface. By profiling and determining where heating losses need to be compensated, we can match the most efficient profile with a single element.

There are two common types of flexible heaters: the older wound-wire devices and foil-based devices. Both use metals with different resistivity and heating characteristics.

Wire heaters use a single or several strands of wire to transfer heat to a tangent point or arc area of its circular heating element. In contrast, the flat surface of foil heaters provides more uniform heating thanks to significantly more surface area devoted to heat transfer.

Find out more, Flexible Heater Elements: Differences and Advantages.

At a Glance: Flex Heater Elements

• Flexible heater performance is heavily influenced by the heating element material, with Stainless Steel 304, CuNi44, and Inconel600 offering different resistance, temperature, and environmental capabilities.
• Foil-based flexible heaters provide more uniform heat distribution than traditional wound-wire heaters because a larger surface area is dedicated to heat transfer.
• Heater profiling helps identify thermal loss areas and optimize element selection, allowing a single heating element design to achieve the desired temperature distribution across the application.

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Stainless Steel 304

With etched foils, Stainless Steel 304 is standard. It has a minimum of 18% chromium and 8% nickel, combined with a maximum of 0.08% carbon. Along with excellent forming properties, stainless steel 304 is corrosion/oxidation resistant thanks to its chromium content. Stainless steel 304 is an excellent heat exchanger with elevated temperatures due to its higher carbon content.

Typical Physical Properties
Density (g/cm3)	8.0
Electrical resistivity at 20°C (Ωmm2/m)	0.68
Temperature factor of resistivity (20°C~600°C) x 10-5/°C	-6
Conductivity coefficient at 20°C (WmK)	17
Maximum Temperature: Mechanical	420°C
Coefficient of Thermal Expansion
Temperature	Thermal Expansion x 10-6/K
20°C - 400°C	16
Specific Heat Capacity
Temperature	20°C
J/gK	0.48

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CuNi44

The copper-nickel alloy CuNi44 is also offered. CuNi44 is characterized by high electrical resistance, high ductility, and good corrosion resistance. It is suitable for use at temperatures up to 400°C.

Typical Physical Properties
Density (g/cm3)	8.9
Electrical resistivity at 20°C (Ωmm2/m)	0.49
Temperature factor of resistivity (20°C~600°C) x 10-5/°C	-6
Conductivity coefficient at 20°C (WmK)	23
Maximum Temperature: Mechanical	600°C
Coefficient of Thermal Expansion
Temperature	Thermal Expansion x10-6/K
20°C - 400°C	15
Specific Heat Capacity
Temperature	20°C
J/gK	0.41

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Inconel600

We also offer Inconel600 as a heating element which offers the highest resistance with no magnetic properties. It is an austenitic alloy with a high nickel content. The high nickel content of the alloy provides good resistance to reducing environments while the chromium content provides resistance to weaker oxidizing conditions.

Typical Physical Properties
Density (g/cm3)	8.5
Electrical resistivity at 20°C (Ωmm2/m)	1.03
Temperature factor of resistivity (20°C~600°C) x 10-5/°C	-6
Conductivity coefficient at 20°C (WmK)	15
Maximum Temperature: Mechanical	1100°C
Coefficient of Thermal Expansion
Temperature	Thermal Expansion x10-6/K
20°C - 400°C	13
Specific Heat Capacity
Temperature	20°C
J/gK	0.46

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Frequently Asked Questions

Quick Links

• What is the difference between foil heaters and wire heaters?
• How is the appropriate flexible heater element selected?
• What are the benefits of Stainless Steel 304 heating elements?
• When should CuNi44 be used as a heating element material?
• What advantages does Inconel600 provide in flexible heater designs?

What is the difference between foil heaters and wire heaters?

Wire heaters use one or more strands of wire to transfer heat to a tangent point or arc area of the heating element. Foil heaters use a flat etched foil design that provides significantly more surface area for heat transfer. This larger heating surface promotes more uniform temperature distribution across the heater. As a result, foil-based heaters are often preferred when consistent heating performance is required.

How is the appropriate flexible heater element selected?

Element selection is based on the heater profile and the application's thermal requirements. Profiling is typically performed by testing heaters at different power levels to determine temperature distribution across the heated surface. Areas experiencing greater heat loss can then be identified and compensated for in the element design. This process helps match the most efficient heating element configuration to the application.

What are the benefits of Stainless Steel 304 heating elements?

Stainless Steel 304 is the standard material used for many etched foil heater designs. It contains a minimum of 18% chromium and 8% nickel, providing good corrosion and oxidation resistance. The material also offers excellent forming characteristics and performs well as a heat exchanger at elevated temperatures. According to the source, Stainless Steel 304 has a maximum mechanical temperature rating of 420°C.

When should CuNi44 be used as a heating element material?

CuNi44 is a copper-nickel alloy characterized by high electrical resistance, good ductility, and corrosion resistance. It is suitable for applications operating at temperatures up to 400°C. The material offers different electrical and thermal properties than Stainless Steel 304, allowing designers to select a heating element that better matches application requirements. CuNi44 is often considered when balancing resistance characteristics and operating temperature needs.

What advantages does Inconel600 provide in flexible heater designs?

Inconel600 offers the highest electrical resistance of the materials presented in the source and has no magnetic properties. It is an austenitic alloy with a high nickel content that provides resistance to reducing environments, while its chromium content contributes resistance to weaker oxidizing conditions. Inconel600 also supports the highest maximum mechanical temperature rating listed, reaching up to 1100°C. These characteristics make it suitable for demanding high-temperature applications.

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Optimize Your Heating Performance Today!

Don't let inefficiencies hold you back. Perfectly profile your heating needs and choose the most effective foil element tailored to your requirements. Dive deep into the unique characteristics of Stainless Steel 304, CuNi44, and Inconel600, and elevate your heat transfer game. From uniform heat distribution to resisting challenging environments, make the right choice for maximum efficiency.

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