| 摘要 |
<p>Thermochemical treatments are made by the ionic bombardment of metals such as steel or alloy steels. The metal workpieces are heated in a furnace to the required temp. before ionic bombardment, the heat from the latter only being used to maintain the workpieces at temp. To improve the temp. uniformity of different workpieces, heating and/or cooling cycles may be alternated with ion bombardment. The initial heating is pref. obtd. by radiation in vacuo; resistance heating; or by hot gas. The pref. furnace includes a sealed chamber which is thermally insulated and contains a heat shield, gas circulation fan, a cathode carrying the workpieces, and inlets for gas or vacuum connection; the wall of the furnace forms the anode. Various types of heating may be used. The process and furnace can be used for ion nitriding and other treatments. The furnace can be used at above 600 degrees C and also employed for carbonitriding, or treatment with B, S, or carbon; and workpieces of different sizes can be treated.</p> |
