Vacuum furnace don't like to "eat" what material?

Vacuum furnace don't like to "eat" what material?

Vacuum furnace is widely accept metal materials, but because of many reasons resulted in the vacuum furnace is unable to process the materials, such as in the technical requirements, need to cost, there are some difference on the craft, vacuum furnace that what kind of material is not "eat"?
Carbon steel, carbon steel price under other steel products, and finished product price is not high also, if there is no allowance is not highly profitable materials or materials processing, forced from cost to consider, or do not use vacuum furnace is better, because the cost of the vacuum furnace is far higher than that of carbon steel prices, really isn't worth while.
N elements: using high temperature materials processing of n elements, not only can produce harmful products material and the sensitivity of the high temperature of n elements is too high, alloying elements using vacuum furnace processing in order to prevent metal material to send out at high temperatures, so generally will be under the condition of high temperature high purity nitrogen partial pressure, cooling using nitrogen charging way, so unfavorable use vacuum furnace.
Special materials: some special material in order to achieve the result that you want to use high temperature processing, some materials need to obtain bainite, some are to get good mechanical properties, isothermal quenching can be used to reach the effect, but the vacuum furnace to achieve some special material of hot working, although with high-pressure gas quenching vacuum furnace for high hardness for Ms points under cold temperature speed faster, will be large deformation effects.