TEMPERATURE MEASURING APPARATUS FOR STEEL PIPE

PURPOSE: To obtain a temperature measuring apparatus which can measure the temperature in the circumferential direction of a steel pipe with good accuracy in a simple constitution, in which a slip ring or the like is not required, which is low-cost and which prevents the generation of a noise or the like by making the angle of rotation do not exceed a specific value. CONSTITUTION: Radiation thermometer sensors 2-a, 2-b which measure the surface temperature of a forge-welded tube 1 are attached to positions which are symmetric with reference to the shaft of a sensor holder 3, the holder 3 is turned by 180 deg.C by means of a circling mechanism 4, and a temperature at 180 deg.C can be measured by one sensor. Since a measuring hole 18-b for the sensor 2-b which measures the lower half of the forge-welded tube 1 is worked so as to face the rotation central axis of the sensor holder 3 and to tilt to the front and rear directions of the holder 3, the scale of the tube, cooling water and the like do not fall into, and adhere to, the measuring hole. Radiant light, from the steel tube, which has passed respective measuring holes 18-a, 18-b is reflected by a reflecting mirror 23 and enters the light receiving part of a radiation thermometer 8.