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The dew point of the atmosphere surrounding the stainless steel mesh belt is raised to 34°C, which corresponds to a water vapor concentration of 260 ppm; as a result, the stainless steel mesh belt can maintain a slight oxidizing environment in high-temperature areas, and the oxides on its surface are not reduced. Furthermore, no decarburization occurred on the surface of the workpiece either. Lowering this temperature from 870°C to 760°C prevents the chromium in stainless steel from reacting with nitrogen in the air. When the temperature is raised to 1120°C, the presence of water vapor in the atmosphere allows chromium oxide to form on the surface of the conveyor belt, thereby preventing a reaction between chromium and nitrogen. At this point, the lifespan of the conveyor belt can be extended by another 1/3 compared to the optimal condition mentioned earlier; in other words, it is 2.7 times longer than the lifespan under conditions without tempering or adjusted atmosphere. This is because of the lower chromium nitride content and larger grains, which are beneficial for the creep properties. In addition to adjusting the water vapor in the atmosphere as mentioned above, carbon dioxide can also be added to the stainless steel mesh belt. This carbon dioxide reacts with hydrogen to form water; both carbon dioxide and water constitute oxidizing atmospheres. By regulating their concentrations, it is possible to keep the stainless steel mesh belt in a slightly oxidized state, while the workpiece remains in a reducing atmosphere. This allows the oxides on the surface of the iron powder to be reduced, thereby enhancing the bonding strength between the powder particles and improving the mechanical properties of the workpiece. Furthermore, the tempering conditions prior to use also have an impact on the mesh belt. If the aforementioned tempering conditions are changed to maintaining the temperature at 760°C (originally 870°C) in flowing air for 28 hours, then switching to N2-3%H2 containing 260 ppm of water vapor and maintaining that temperature for 2 hours, followed by raising the temperature to 1120°C within 14 hours, production can only begin after maintaining that temperature for 8 hours.