Steel rods and pipes are mainly heat-treated using roller hearth furnaces. The high temperature consistency and low energy consumption of these furnaces, normally gas-fired, ensure reproducible quality and short treatment times. The processes used for heat treating non-alloyed and alloyed carbon steel pipes at temperatures between 450°C and 1050°C include stress relieving, recrystallizing, normalizing, soft annealing and spheroidizing in indirectly fired continuous roller hearth furnaces. For the spheroidizing of pipes made from high-carbon ball bearing steel, vacuum vestibules to completely isolate the furnace atmosphere from the surrounding air are essential, at least at the furnace entry. Vacuum vestibules are also needed at the entry and exit of continuous roller hearth furnaces for the bright solution annealing of high-alloy austenitic pipes. In the heat treatment of copper alloy bars and pipes, zinc, which can be easily oxidized, is the critical element in the alloy. Rapid cooling is essential to ensure that the zinc is kept in solution. This can be achieved using optional high-convection cooling chambers with a hydrogen atmosphere.
Wellman's broad experience in building Roller Hearth Furnaces includes direct-fired and atmosphere furnaces for temperatures to 2100°F (1150°C). Fuel-fired or electrically heated designs are available.
These furnaces are ideal for lamination annealing, tube annealing and many other processes. For example, a successful Roller Heath line was provided for reheating molybdenum and tungsten sheets for rolling. It features a unique pulse-fired combustion system.
Nominal temperature: up to 1.150oC
Capacity: from 700 to 4500 kg/h
ELTERMA S.A. Roller hearth furnaces can be designed to transport large loads directly on the furnace rollers or for smaller loads can be carried in heat resistant work baskets or trays.
The rollers are driven via a system of roller chains linked to an inverter driven motorized gearbox, which gives a smooth constant drive to the rollers.
Roller hearth furnaces systems guarantee minimal surface distortion after quenching, particularly important to the bearing industry where ELTERMA S.A. have supplied a number of these lines.
Main advantages of ELTERMA S.A. Roller Hearth furnaces are:
Multi-zones heating system in order to provide the required temperature gradient through the furnace
Close control of roller hearth drive system in the furnace ensures smooth even transport of the load or basket through the furnace
Full control de-carbonization level of the load via close atmosphere control
Efficient work loading and unloading systems.
Lindberg Roller Hearth Furnaces combine the latest technology in process controls, atmosphere systems, and material handling to give you a complete cost-efficient means of heat processing in many different applications.
Lindbeg roller hearth furnaces are available in either electric powered or gas-fired models. Electric heating offers reliable low-maintenance operation using elements tailored to your application. Start up and shut down procedures are simple and our superior element designs provide precise temperature control and long life. Gas-fired models use single-end recuperative tubes (SERTs) that provide economical rapid heating. The exhaust stream preheats air coming into each burner. This preheated combustion air greatly increases the efficiency of the combustion process thus lowering fuel consumption.
Features / Benefits
Complete, systems ready for operation
Low operating costs and long component life
Easy and safe operation and process repeatability
Increased productivity
Convenient access to controls and maintenance items
Easy loading and unloading
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