SL 414-2007 "Asphalt softening point tester calibration procedure" applies to the first calibration of asphalt softening point tester, subsequent calibration and in-use calibration. The purpose of this procedure is to standardize the calibration conditions, items, methods, result processing and calibration cycle to improve the calibration mass. Before performing the calibration, it is necessary to be fully prepared and strictly follow the operating procedures to ensure the integrity of the calibration results. Asphalt softening point tester is used to determine the softening point of asphalt to evaluate its consistency characteristics. Measurement performance requirements such as thermometer, heating rate, ball mass, sample ring size, etc. are described in detail to ensure the accuracy and Reliability of the test instrument.