What Users Say About APM Tubes

Case History #1
In 1993, GKN Automotive, a manufacturer of automotive driveline components, converted four Ipsen furnaces at its Mebane, NC plant from graphite bayonet elements and ceramic radiant tubes to bayonet elements and tubes fabricated from Kanthal APM iron/chrome/aluminum alloy from Custom Electric.

According to GKN, heating element life improved from 12 months to more than three years, and tube life improved from nine months in the charge end of the furnace and 18 months in pusher zones to more than five years.

Switching to APM elements and tubes had a significant impact on costs. Based on GKN maintenance records, the four six-zone furnaces previously had to be taken out of service three or four times a year, for a week at a time, to replace heating elements and tubes. Today, only two shutdowns a year are required. This saves GKN more than $200,000 annually in lost production. In addition, furnace downtime has been reduced from 31% to 10%; maintenance costs have been reduced by $8,000 a year; annual spending on replacement elements and tubes was reduced by $24,000; and furnace productivity increased by 20%.

Case History #2
When commercial heat treater Bodycote Thermal Processing rebuilt a gas-fired batch furnace at its Minneapolis plant, it replaced cast radiant tubes with Kanthal APM tubes. APM tubes are extruded from an iron/chrome/aluminum powder metal alloy. They have a much longer high temperature service life than conventional radiant tubes. APM radiant tubes also reduce furnace downtime and maintenance costs, and contribute to improved furnace performance.

According to Bodycote, the rebuilt gas furnace has 48% better thermal efficiency, 59% lower energy consumption, and 25% shorter cycle times. Overall furnace productivity improved by 11%.

Case History #3
The Lindure® process is a method of heating that requires precise control of furnace temperature. When Bodycote Thermal Processing introduced the Lindure process to its Indianapolis plant, it contacted Kromschroder, Inc., Hudson, OH, to rebuild a 30"x48"x30" integral quench furnace.

Kromschroder, a technology partner of Custom Electric, focused on three objectives: lower fuel consumption, shorten cycle times, and improve radiant tube life.

The first two objectives were achieved by installing six Kromschroder BICR single-ended, self-recuperative burners and a PF-19 flame management system. This package provided a 65% improvement in thermal efficiency, a 22% reduction in energy consumption, 40% lower fuel costs, and 30% shorter cycle times.

To eliminate premature tube failure, the major cause of furnace downtime, lost production, and high maintenance costs, APM tubes were installed.

Custom Electric supplied six 5.7 in. diam. x 68-in. long single-ended APM alloy tubes for the Bodycote integral quench furnace. After three years of service, the APM tubes exhibited no signs of wear.

(Lindure is Bodycote's proprietary thermochemical surface heat treatment generally known as ferritic nitrocarburizing.)

More Case Histories:
APM alloy radiant tubes are used worldwide in a variety of applications. Contact Custom Electric for more information on:

• Electric furnaces
• Gas furnaces
• Seal quench furnaces
• Aluminum and zinc melting furnaces
• Aluminum and zinc melting furnaces
• Holding furnaces
• Aluminum dosing furnaces
• Wire annealing furnaces
• Sintering furnace muffles
• Die casting machines
• Heat treating
• Annealing/Galvanizing lines
• Waste incineration