一、问题的提出正阳县球铁铸造厂出口西德约翰·迪尔公司和美国天纳克公司的球墨铸铁件均需要等温正火热处理,以满足机件材质的要求。每年需要处理球铁铸件34个品种,42万件,总重高达900t之多。球铁铸件进行热处理的炉型是RJX—75—9箱式电阻炉。这种电阻炉体是用耐火 First, the problem raised Zhengyang County Ductile Iron Foundry exports West Deere John Deere company and the United States Tenneco ductile iron castings are isothermal orthothermal treatment to meet the requirements of mechanical parts. There are 34 varieties of ductile iron castings to be processed each year, 420,000 pieces, weighing up to 900 tons. Ductile iron casting heat treatment furnace is RJX-75-9 box resistance furnace. This resistance furnace is fire-resistant