Electric Resistance Heating Furnaces — March 2025

Tianli Expands RT2 Series Electric Resistance Heating Furnaces for Precision Heat Treatment

Combustion-free heating with multi-zone closed-loop PID control — 14 standard models spanning 45 kW to 950 kW and working temperatures of 650 °C, 950 °C and 1,200 °C.

XINXIANG, Henan, China — March 2025 — Tianli Thermal Equipment has expanded its RT2 series of electric resistance heating furnaces, an enclosed insulated-chamber furnace line that converts electrical energy into heat through resistance heating elements. Because the process produces no combustion exhaust, the furnaces deliver clean operation and high-precision temperature control — characteristics that have made them a standard choice for precision heat treatment processes.

Engineering scope

Drawing on manufacturing experience dating back to 2003 and more than 200 national patents, Tianli engineers and produces the complete set in house: steel structure, refractory lining, heating elements, hot-air circulation system and full electrical control system. Units can operate as standalone machines or be combined into automatic production lines. The company describes the series as easy to install, convenient to transport and low in operating and maintenance cost — a combination that has supported exports to Russia, the UAE (Dubai), Thailand, Vietnam, Oman and other markets since 2015.

Typical applications

• Annealing — relieve internal stress, reduce hardness and improve ductility for machining

• Normalizing — refine grain structure and optimize comprehensive mechanical performance for castings and forgings

• Tempering — remove quenching residual stress, adjust hardness, enhance toughness and stabilize dimensions

• Quenching heating and aging treatment — precision thermal processing for alloy steel, aluminum alloy and other workpieces

Key advantages

1. Clean electric heating with high control accuracy. Premium resistance heating elements generate heat without combustion byproducts, supporting a clean workshop environment. Multi-zone closed-loop PID temperature control provides fast response and high precision, accurately executing full heating–soaking–cooling curves for components that require strict thermal conditions.

2. Versatile structural design. The series is available in bogie-hearth, box-type and other configurations. The bogie-type model uses a motor-driven rail trolley: heavy workpieces are loaded outside the furnace, and the trolley moves in and out automatically — ideal for large-size, heavy-weight castings and forgings. Modular design simplifies installation, transportation and relocation.

3. Advanced thermal insulation. A multi-layer composite refractory and insulation lining minimizes heat loss and heat storage, while optimized hot-air circulation ensures a uniform temperature field inside the chamber — securing consistent batch-to-batch quality while lowering energy consumption.

4. Custom-built Tianli PLC control system. The in-house electrical control system uses key industrial-grade components from Schneider Electric, ABB, Siemens, Delta and Yudian (Xiamen). It offers HMI touch-screen operation, stored recipes for annealing, normalizing, tempering and aging, and one-click automatic execution of the full process. Safety interlocks cover overtemperature protection, thermocouple break alarm, furnace-door and trolley limit switches, overload protection and an emergency-stop circuit. Temperature curves, runtime data and fault records are logged automatically, with data export meeting traceability standards for military and nuclear-industry projects. Multi-furnace networking with upper-computer monitoring supports centralized plant management.

5. Custom-engineered design and global service. Furnace dimensions, charge capacity and working temperature can be customized to workpiece specification and plant layout. Backed by long-term cooperation with research institutes and universities, Tianli provides process guidance for special materials, turnkey delivery, after-sales service and long-term spare-part supply for domestic and overseas projects.

Application industries

Military, aerospace, nuclear power, pressure vessel, boiler, hoisting machinery, metallurgical casting and non-ferrous metal processing.

From the workshop floor: tuning zones, not just setpoints

A furnace chamber several metres long rarely heats evenly on paper. Engineer Zhang, who designs Tianli’s control systems, was called in when a customer planned to heat-treat boiler shells six metres long in a single charge. His concern was not the setpoint but the ramp: a fast rise would leave the ends behind and put thermal stress into the workpiece. He split the chamber into independently controlled zones, wrote a rate-limited heating curve into the PLC recipe, and set a soak band wide enough that the whole charge would sit inside tolerance before the next step. The furnace now runs the curve unattended, and the customer reuses the same recipe as a template for every later boiler shell batch. It is a small piece of engineering that removes a recurring argument about whether the furnace is out of tolerance.

Specifications at a glance