Daido Develops Electric Radiant Tube Heater 'D2-ERTH' Contributing to Decarbonization of Heat Treatment Furnaces, to Begin Sales in August 2026

Daido Steel Co., Ltd. (President: Tetsuya Shimizu) has developed an electric-powered radiant tube heater (named D2-ERTH (Daido Dual-Mode Electric Radiant Tube Heater), trademark application pending; hereinafter referred to as 'this heater') (Figure 1) as a heating device contributing to carbon neutrality in heat treatment furnaces, and will begin sales in August 2026. This heater can be applied broadly to various heat treatment furnaces currently using radiant tube burners (*1) as heating equipment. By simply removing the existing burner and replacing it with this heater, electrification can be achieved without major equipment modifications. Furthermore, replacing burners with this heater significantly reduces CO2 emissions directly generated from the heat treatment furnace, greatly contributing to Scope 1 (*2) reduction, and when combined with CO2-free electricity, it also helps suppress increases in Scope 2 (*3) emissions.

Through this technology, the company will continue contributing to advancing carbon neutrality across supply chains.

Figure 1. Appearance of the new radiant tube heater (D2-ERTH (Daido Dual-Mode Electric Radiant Tube Heater))

1. Background

In pursuit of Japan's government goal of achieving carbon neutrality by 2050, demand for greenhouse gas emission reductions continues to grow each year, requiring corresponding measures in heat treatment furnaces. Since introducing the first STC furnace (*4) in 1980, Daido has sold over 350 units worldwide, with many still in operation today. In 2016, the company developed and launched the high-efficiency heat exchanger DINCS (*5), and in 2022 introduced the premium STC furnace equipped with a high-performance energy-saving system, consistently providing products that contribute to reducing CO2 emissions across supply chains. More recently, Daido has been developing hydrogen burners (*6) and evaluating their implementation in STC furnaces, continuing efforts toward achieving full carbon neutrality for STC furnaces.

In this context, reducing CO2 emissions through electrification of heat sources and utilizing CO2-free electricity is considered an effective transitional approach until a full hydrogen society is realized. To make this solution applicable to existing STC furnace users, the company has newly developed this heater capable of reusing existing radiant tubes.

2. Features of 'D2-ERTH'

Heater capacity: 45kW/unit (*equivalent output to existing STC furnace radiant tube burners)

Enables direct reuse of existing radiant tubes, allowing electrification with minimal modifications

Eliminates burner flue gas, resulting in zero heat loss from exhaust gas and zero NOx emissions

Includes radiant tube cooling function for slow cooling during annealing processes, eliminating the need to add separate cooling circuits after heater conversion

Enables precise control of input current, improving furnace temperature control performance compared to conventional burner flame control

Figure 2. Photo of D2-ERTH prototype

3. Other Information

Patents Domestic application filed (international application pending) Japanese Patent Application No. 2026-054758

D2-ERTH (Daido Earth) Product Page https://www.daido.co.jp/products/machinery/lineup/heat/d2_erth.html

<Reference: Past Press Releases> Daido Develops Unique Radiant Tube Hydrogen Burner, Successfully Tests Hydrogen Co-firing and Dedicated Firing, Achieving Practical Application Feasibility (December 14, 2022) https://www.daido.co.jp/about/release/2022/221214_burner.html

Glossary

*1 Radiant Tube Burner A heating device widely used in atmosphere-controlled heat treatment furnaces such as Daido's STC furnaces. The tube surface is heated by internal combustion, and the workpiece is indirectly heated via radiant heat. Unlike direct flame heating, combustion exhaust gas is not released into the furnace, enabling precise control of furnace atmosphere composition and high-quality surface heat treatment of materials.

*2 Scope 1 Greenhouse gas emissions that are directly released by a company or organization.

*3 Scope 2 Greenhouse gas emissions released indirectly through the use of electricity, heat, or steam purchased from external suppliers by a company or organization.

*4 STC Furnace Equipment enabling versatile heat treatment of small-lot, multi-variety products such as wire coils and cold-forged components. Two types are available: standard STC furnaces and premium STC furnaces equipped with high-performance energy-saving systems.

*5 DINCS (Dinks) A high-efficiency heat exchanger enabling highly efficient heat recovery from burner exhaust gas.

*6 Hydrogen Burner A radiant tube burner using hydrogen as combustion fuel, developed for achieving carbon neutrality.