Vacuum hardening process and vacuum furnace system composition

---

Vacuum hardening process

The typical process of vacuum hardening can be divided into three stages: exhaust stage, heating stage, and cooling stage.

(1) Exhaust stage. After the workpiece is loaded into the furnace, the furnace chamber is first exhausted to create a vacuum environment to prevent the workpiece from oxidizing during the heating process.

(2) Heating process. When the pressure in the furnace reaches the ultimate vacuum degree, the workpiece begins to be heated. During the heating process of the workpiece, 2 to 3 insulation stages are required to ensure uniform heating of the workpiece, reduce thermal stress, and prevent deformation of the workpiece. In the later stage of the heating stage, a small amount of protective gas is filled in to accelerate the heating of the workpiece.

(3) Cooling stage. After the workpiece is heated to the highest temperature and kept warm for a period of time, neutral or inert gas is filled in for cooling, and a fan is used to force the cooling gas to circulate.

System composition of vacuum hardening furnace

(1) Furnace body. The furnace body is the main part of the vacuum hardening furnace, which consists of a furnace shell and a heating chamber.

(2) Vacuum system. The vacuum system provides power for the pressure change in the vacuum hardening furnace. The vacuum system consists of a vacuum container, a vacuum pump, a vacuum valve, connecting pipes and vacuum measuring instruments.

(3) Inflating system. The inflation system includes an inflation and recovery device for cooling gas (neutral or inert gas).

(4) Cooling system. When cooling the workpiece, driven by the fan, the cooling gas enters the heating chamber from the lower door, and the gas that absorbs the heat of the workpiece flows out from the upper door, exchanges heat with the heat exchanger, and the cooled gas flows in through the lower door, thus forming a cycle.

(5) Pneumatic system. This system provides power for the movement of the upper and lower doors of the heating chamber and the opening and closing of the valves in the system pipeline.

(6) Electronic control system. The electronic control system is like a human brain. It issues instructions to each link in the production process and controls the opening and closing of pumps and valves and the operation of heating elements.

Vacuum Hardening Furnace

Model	Working Zone Size (W*H*L)	MAX Temperature	Cooling Gas Pressure	Ultimate Pressure	Temperature Uniformity	Loading Capacity
RVGQ-446	400*400*600mm	1350℃	6/10/15/20Bar	6.7*10-4Pa/6.7*10-1Pa	±5℃	200Kg
RVGQ-557	500*500*700mm	1350℃	6/10/15/20Bar	6.7*10-4Pa/6.7*10-1Pa	±5℃	300Kg
RVGQ-669	600*600*900mm	1350℃	6/10/15/20Bar	6.7*10-4Pa/6.7*10-1Pa	±5℃	500Kg
RVGQ-7710	700*700*1000mm	1350℃	6/10/15/20Bar	6.7*10-4Pa/6.7*10-1Pa	±5℃	700Kg
RVGQ-8812	800*800*1200mm	1350℃	6/10/15/20Bar	6.7*10-4Pa/6.7*10-1Pa	±5℃	1000Kg
RVGQ-9915	900*900*1500mm	1350℃	6/10/15/20Bar	6.7*10-4Pa/6.7*10-1Pa	±5℃	1200Kg
Remark: The working zone of equipment could be customized base on customer’s production.