Protective Atmosphere for Forging

The thing that comes to my mind is nitrogen - it's probably the cheapest. Some plants have their own niquid nitrogen tank/supply system. If not, the other option is compressed nitrogen in cylinders. The supplier can tell you how much will be available per cylinder and can recommend a regulator for the flow rate you need. The volume of the protective atmosphere will determine how many cylinders will need to be used at any given time to maintain the inert atmosphere.

A note of caution - breathing nitrogen feels just like breathing air. If someone is in a nitrogen environment, they will quickly pass out before they even know what's happening. Then, with no oxygen, they will die. Be careful! Find out more here.

Hope this helps,

Mike

1) If the furnace is heated with electricity there are 2 common methods.

a)One would be to use an inert gas (Nitrogen as mentioned by the previous contibuter.) This method involves a fairly high purge rate each time the furnace door is opened as a positive pressure is used to ensure that outside air (Oxygen) is not allowed to enter the furnace chamber. As long as the area around the furnace is well ventilated to disipate the inert there should be very little risk of asphixiating the operator.

b)The second method would be to use a combustible gas as the purge medium (carbon monoxide (CO) produced from a hydrocarbon fuel source in an exothermic generator or Hydrogen from an industrial gas supplier). As the combustible gas actively scavenges any free Oxygen from the atmosphere inside the furnace chamber the purge rate is appreciably lower than using an inert atmosphere. As the purge gas is combustible and it will be at furnace temperature it is usual flare the excess gas off and to provide a source of ignition to maintain a flame at the flare point and not allow the combustible gas to build up around the furnace.

2)If the furnace is direct gas fired then it is a lot easier. A competent gas engineer would simply set the combustion to be gas rich and this would automatically create a reducing atmosphere rich in CO with little or no free oxygen.

I hope this helps