Methods for monitoring or controlling the ratio of hydrogen to water vapor in metal heat treating atmospheres
Methods for monitoring a heat treating atmosphere supply a preselected gas atmosphere at a preselected temperature to a heat treating furnace. The preselected temperature is not greater than a temperature at which wustite (FeO) forms. The methods sense the preselected gas atmosphere and the preselected temperature and compute a computed ratio of gaseous hydrogen H 2 (g) to water vapor H 2 O (g) for the preselected atmosphere as a function of the sensed values.
1. A method comprising
supplying a preselected gas atmosphere to a heat treating furnace,
maintaining the preselected gas atmosphere inside the furnace at a preselected temperature not greater than a temperature at which wustite (FeO) forms,
sensing the preselected gas atmosphere and providing a first electrical input that varies according to oxygen content of the preselected atmosphere,
sensing the preselected temperature and providing a second electrical input that varies according to temperature of the preselected atmosphere, and
computing a computed ratio of gaseous hydrogen H 2 (g) to water vapor H 2 O (g) for the preselected atmosphere as a function of the first and second electrical inputs.
2. A method according to claim 1
further including outputing the computed ratio.
3. A method according to claim 1
further including displaying the computed ratio.
4. A method according to claim 1
further including recording the computed ratio.
5. A method according to claim 1
further including controlling the preselected gas atmosphere based, at least in part, upon the computed ratio.
6. A method according to claim 1 further including
comparing the computed ratio to a selected set point to generate a deviation, and
outputing the deviation.
7. A method according to claim 6
further including controlling the preselected gas atmosphere based, at least in part, upon the deviation.
8. A method according to claim 1
wherein supplying includes supplying a preselected gas atmosphere comprising an H 2 /N 2 atmosphere.
9. A method according to claim 1
wherein supplying includes supplying a preselected gas atmosphere comprising CO, CO 2 , H 2 , and H 2 O.
10. A method according to claim 1
wherein supplying includes supplying a preselected gas atmosphere comprising steam.
11. A method according to claim 1
wherein maintaining the preselected gas atmosphere includes maintaining a temperatures not greater than about 1000 degrees Fahrenheit.