SL 412-2007 "Asphalt Penetration Calibration Regulations" are applicable to the first calibration, subsequent calibration and in-use calibration of asphalt penetrators. This standard refers to the "Asphalt Penetration Determination Method" (GB/T 4509), which aims to standardize the calibration conditions, items, methods and result processing, and clarify the calibration period to improve the calibration mass. Before performing the calibration, it is necessary to fully prepare and strictly implement the operating procedures to ensure the Reliability and completeness of the calibration results. In addition, in addition to meeting the requirements of this standard, the calibration work must also comply with the relevant national standards in force to ensure the accuracy and Reliability of the asphalt penetrator.