VD Furnace Vs. VOD Furnace

VD (Vacuum Decarburization) furnace and VOD (Vacuum Oxygen Decarburization) furnace are both important vacuum refining equipment in the field of steel smelting. There are several differences between them, mainly reflected in the working principle, main functions, equipment composition and production products. 

1. Working principle 

VD furnace: Through the operation of the five-stage steam jet pump, the working vacuum degree of the vacuum chamber reaches below 67Pa, and the refining purpose is achieved by the effect of negative pressure. The VD furnace mainly removes oxygen from the steel through carbon-oxygen reaction, and removes sulfur from the steel through the full reaction of alkaline slag and molten steel, and can effectively reduce the hydrogen and nitrogen content in the steel.

VOD furnace: Under vacuum conditions, decarburization is carried out by blowing oxygen and stirring with argon. The VOD furnace adds an oxygen gun and its lifting system and oxygen supply system on the upper part of the vacuum sealing cover to blow oxygen into the molten steel in the ladle for decarburization. It has the functions of decarburization, deoxidation, degassing, desulfurization and alloying. 

2. Main functions

VD furnace: mainly used to reduce the hydrogen and nitrogen content in steel, remove oxygen and sulfur in steel, suitable for steel types that are not very demanding, such as carbon steel, alloy steel, ordinary bearing steel, ordinary oil pipeline steel, etc.

VOD furnace: mainly produces ultra-low carbon, nitrogen stainless steel and other products, with high requirements for the quality of refractory materials . It is often combined with electric furnaces or converters, and the process flow usually adopts a double method. 

3. Equipment composition 

VD furnace: mainly includes vacuum tanks, vacuum tank covers and their tank cover lifting and moving trolleys, vacuum feeding devices, control and monitoring equipment, etc. The equipment is simple, the investment is small, and the operation is relatively simple. 

VOD furnace: on the basis of VD furnace, key equipment such as oxygen guns, oxygen blowing devices, oxygen supply systems, as well as auxiliary equipment such as temperature measuring devices and end point control instruments are added. The equipment composition is more complex and the requirements for refractory materials are also higher. 

4. Production time and efficiency 

VD furnace: the normal working time is about 30 minutes, and the production efficiency is relatively high. 

VOD furnace: The normal working time is about 1 hour. Although the time is longer, the products it produces have higher purity and performance. 

To sum up, VD furnace and VOD furnace each have their own unique application value in the field of steel smelting. VD furnace is widely used in steel grades that are not very demanding due to its advantages of simple equipment, low investment and easy operation; while VOD furnace occupies an important position in the high-end steel market with its ability to produce high-end products such as ultra-low carbon and nitrogen stainless steel. Users can choose appropriate refining equipment according to specific needs.