新型离子渗氮炉

针对国内离子渗氮炉使用中常见的问题，从减少炉壁散热损失、增加底座承重能力、提高电极连接可靠性等方面提出了改进设计方案。新的设计中取消了大部分的炉壁冷却水夹层，增加了真空隔热层，升温时减少热量损失，降温时充入压缩空气强制对流冷却，配合快速冷却装置，增加导热系数，加快工件冷却速度。采用圆弧型封头底座，增大炉体承重能力，并改善气体流动的均匀性。输电阴极采用迷宫式屏蔽结构，作为绝缘体的熔铸云母全部屏蔽在钢制外罩之内，不会因放电而损坏；阴极与底座之间采用可靠的密封方式，长期使用不漏气。实际使用表明，新型离子渗氮炉可大大降低热量损失，增加承重能力，维护保养方便；输电阴极使用3年不用拆卸，工作稳定可靠，劳动生产率比常规的离子渗氮炉提高30％。

A New Type Plasma Nitriding Furnace

In view of problems commonly encountered in production operation of plasma nitriding furnaces made in China, an improved design was brought forward to cut down heat loss from the furnace wall, enhance load-bearing capacity of the furnace bottom and increase reliability of the electrode connections.In the new design, most of the water-cooling cavity in the furnace wall was substituted by a vacuum heat insulating cavity.This vacuum cavity can obstruct heat loss during heating, promote convection cooling when filled up with pressed air during cooling, and with the help of a fast cooling unit,raise the cooling rate of the workpiece after nitriding.The bottom of the furnace was rockered which exhibits greater load-bearing capacity and uniforms gas flow in the furnace.A labyrinthine shielding of cathode was employed to shield the melt cast insulating mica entirely inside a steel cover,avoiding damage from electric discharge. The improved sealing of cathode with the bottom of furnace was also tight and safe.Production operation has shown that the newly designed plasma nitriding furnace is of low heat loss,high load-bearing capacity and easy maintenance. The cathode has been in operation for more than three years without any troubles. Thirty percent of production rate can be obtained compared with conventional plasma nitriding furnaces.