A heat treating furnace heated by electric elements hardens, anneals and stress relieves very effectively. Today’s heating elements operate at higher temperatures, last longer and offer gear manufacturers opportunities to reduce thermal processing costs. Energy and environmental concerns should further expand the use of electric furnaces.
Gas-Fired Furnaces
It was not until the 1950s that the United States had a pipeline network and power grid sufficient to allow natural gas and electricity to be the primary energy sources for energy-intensive industrial applications requiring a heat treating furnace. Today, heat-treating is a $20 to $25 billion industry serving more than 18,000 manufacturers. Gas-fired heat treat furnaces outnumber electric furnaces in the U.S. because natural gas is plentiful and, relatively speaking, affordable.
Electric Furnaces
With respect to performance, both electric and gas-fired furnaces do an excellent job case hardening, through hardening, annealing, normalizing and stress relieving. However, there are characteristics of electric furnaces which are becoming better appreciated. For example, a uniform heat pattern is achievable with proper element placement. Energy efficiency exceeds 90 percent; compared to from 60 to 80 percent with gas furnace. Electric furnaces also are quiet, safe and pollution free.
Heating Elements
Today?s electric furnace is a highly engineered piece of equipment. It is tightly constructed, better insulated and energy efficient. Electronics monitor and control every stage of processing. Heating elements are the most important components of an electric furnace. Heating elements may only account for about 10 percent of the costs to operate a large, modern heat treat furnace, but they dictate or influence the entire heat treat process, everything from furnace operating temperature and heat cycle times to maintenance costs.
Energy Efficiency
Heat treat facilities consume huge amounts of electricity and natural gas. In today?s ?Green? world, this raises a red flag. Some industry analysts suggest the heat treat industry should reduce energy consumption by as much as 80 percent by 2020. This scenario favors electric furnaces because they already are 90 percent energy efficient, says Custom Electric.
Renewable Energy
For the purpose of protect the environment and lowering oil imports, Washington politicians could mandate that 80 percent of America?s energy come from renewable sources by 2050. The plan is to replace or supplement electricity produced from fossil fuels with electricity generated by wind turbines, solar panels, hydroelectric turbines, biomass and heat trapped beneath the surface of the Earth. This scenario is ambitious and will be enormously expensive, but favors electric furnaces.