Steam
treating steel is a process that results in metal that has increased
corrosion resistance, better wear resistance, increased surface hardness, a
more uniform finish, less porosity and increased density. It is the controlled
oxidation of metals that results in a thin layer of oxide on the surface of the
component. This can help the part to retain lubricants better and more
efficiently.
Steam treating is also done to improve the aesthetics of a
steel tool because it results in a decorative coating that is blue-black or
blue-gray. And increased wear resistance is great for tools that are going to
be inventoried for awhile.
The three most important aspects of the steam treating
process are atmosphere, time and temperature. The first step is to heat the
component to a temperature that is above 300 degrees Fahrenheit. The part will
usually be heated to above 700 degrees Fahrenheit before it is exposed to
steam. This ensures the entire load of parts is above 300 degrees Fahrenheit.
Once the part is at 700 degrees, the component is hit with dry steam. The water
vapor in the steam will then react with the iron in the part.
The ferrous parts are then heated to about 1000 degrees
Fahrenheit. They are then held in the dry steam for a set amount of time,
depending on the application. After that, the parts are generally allowed to
cool naturally in the air.
Usually, the lower the density of the powder metal part, the
more of an improvement there will be to the part because of the larger number
of interconnected voids.
For more information on steam treating steel, call Hi-Tech
Steel Treating at 1-800-835-8294 or Contact Us.
