To automatically retain the conditions of gas to fixed ones regardless of the change of the temp. of the outside air and to steadily form and retain flame.
In a thermal spraying method in which flame F of oxygen-fuel is used as a heat source, a thermal spraying material is melted by the flame F, moreover, compressed air is jetted from the circumference of the flame F, and the melted thermal spraying material is made into fine melted droplets, which are sprayed on the surface of a base material to form coating, the feed of the oxygen-fuel gas and compressed air is made into fixed value by a mass flow controller 40. The mass flow controller 40 detects the mass flow rate in the case the temp. and pressure of the feeding gas are changed even without executing their correction and controls the same in such a manner that the detected value is made the fixed one, so that, even in the case the temp. of the outside air is changed, the gas conditions are retained to the set value, and desired thermal spraying conditions can always be obtained. When automatically optimum conditions can be obtd. in this way, even in automatic thermal spraying by a robot, stable and homogeneous sprayed coating can be obtd.
MIKI RYOJI
SUZUKI TADAHIKO
MATSUURA EIJI
NIPPON WELDING ROD KK
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