Method and apparatus for determining soluble gas content

The combination comprising:

• (a) a heat resistant probe for directing a flow of carrier gas into and circulating the same in a body of molten metal of a known alloy and temperature in a process for determining the amount of soluble gas contained in the molten metal, said flow of carrier gas accumulating molecules of the soluble gas contained in said metal until equilibrium occurs at a measurable pressure,
• (b) means for sensing the pressure of said equilibrium and for developing electrical signals representative of said pressure,
• (c) means insertable into said molten metal for sensing the temperature thereof and for developing electrical signals representative of said temperature,
• (d) means for directing said signals to a computing device programmed to:
• (1) assume an inactive operational mode until activated,
• (2) become activated when the probe is heated to a certain preheat temperature before it is lowered into the molten metal,
• (3) ask for a number representing the degree in which the gas is soluble in the alloy of the molten metal,
• (4) wait for the temperature of the probe to attain the preheat temperature,
• (5) order purging of the probe and means for sensing equilibrium pressure with the carrier gas,
• (6) ask for insertion of the probe into the molten metal, and thereafter,
• (7) stop the purging process;
• and
• (8) circulate the carrier gas through the probe and into the molten metal, and through the means for sensing equilibrium pressure, said carrier gas accumulating free molecules of the gas contained in the molten metal, said computing device, in addition, being:
• (1) programmed to accurately compute the amount of the gas contained in the molten metal from the signals of equilibrium pressure and temperature of the molten metal, and from the solubility number, and
• (2) provide a direct readout of said computation.