Views: 0 Author: JC Publish Time: 2026-06-16 Origin: Site
Electric heating tubes enjoy a wide range of applications nowadays. They can heat liquids such as water and oil, warm metal mold blocks, and serve air heating scenarios including pipelines and paint baking rooms. Many people may wonder how electric heating tubes generate heat, what materials they consist of, and the functions of each component. This article will answer all your questions.
An electric heating tube is composed of the following core components:
Metal shells are the most widely adopted type for electric heating tubes, with common materials including copper, iron and stainless steel.
Copper heating tubes are mostly used for civilian water heating equipment. Their advantages lie in low material cost, while the downsides are susceptibility to copper patina formation and poor high-temperature resistance.
Iron heating tubes are commonly applied to oil heating and air heating systems. They are unsuitable for water heating, as they tend to rust rapidly when exposed to water, resulting in a short service life.
Stainless steel heating tubes dominate the market thanks to abundant grade options. Different stainless steel grades can be selected according to specific service environments and operating temperatures:
Grade 304 stainless steel: Standard choice for water heating, and suitable for working temperatures between 300°C and 400°C.
Grade 316 stainless steel: Ideal for heating corrosive liquids.
Grade 321 stainless steel: Used at an operating temperature of 500°C.
Grade 310S stainless steel: Applied for working temperatures up to 700°C.
As the core heating element of an electric heating tube, resistance wire produces heat once energized, which is the fundamental heating principle of the product.
Two mainstream types of resistance wire are used in electric heating tubes: Fe-Cr-Al wire and Ni-Cr wire.
Fe-Cr-Al Wire
It can withstand temperatures up to approximately 1200°C. It is a popular choice for heating tubes due to its high temperature resistance and relatively low cost.
Ni-Cr Wire
It also has a temperature resistance of around 1200°C, yet features better flexibility compared with Fe-Cr-Al wire. It is normally deployed in heating environments with constant vibration, though it comes with a higher cost.
For electric heating tubes deployed in high-standard working conditions, Kanthal wire and German imported resistance wire are also available options.
The filler is densely packed between the resistance wire and outer shell, functioning as both an insulator and a heat conductor. This is the reason why the exterior surface of an electric heating tube carries no electric current.
Quartz sand was previously the mainstream filler material, but it has been replaced by upgraded magnesium oxide powder. The improved magnesium oxide powder boasts much higher purity and dryness, greatly boosting the heating tube’s heat conduction and insulation performance.
Magnesium oxide powder is categorized into low-temperature, medium-temperature and high-temperature grades for selection based on operating temperature requirements.
The terminal stud is connected to the resistance wire inside the heating tube, and its primary function is to connect power cables for power supply.
Terminal studs are manufactured from iron, copper, stainless steel and other materials.
High-temperature sealing glue is generally used for sealing electric heating tubes. The sealing glue prevents moisture from being absorbed into the tube interior, which would otherwise cause electric leakage.
After sealing with glue, a ceramic bead is additionally fitted to provide extra insulation for regular heating tubes.
These auxiliary fittings secure power cables, and are commonly made of copper, iron or stainless steel.
The above six parts form the core structure of standard electric heating tubes, with a full breakdown of their respective manufacturing materials. Complex customized electric heating tubes may also be equipped with extra parts such as flanges, fixing baffles, fins and fasteners.
