本标准涵盖尺寸为NPS 26至NPS 60的管法兰的压力温度额定值、材料、尺寸、公差、标记和测试。包括额定等级代号为75、150、300、400、600和900的法兰，要求采用国际单位制（公制）和美国惯用单位，螺栓直径和法兰螺栓孔以英寸单位表示。本标准仅限于铸造或锻造材料制成的法兰和铸造、锻造或板材制成的盲法兰。

This standard covers pressure-temperature ratings, materials, dimensions, tolerances, marking, and testing for pipe flanges in sizes NPS 26 through NPS 60. Included are flanges with rating class designations 75, 150, 300, 400, 600, and 900 with requirements given in both SI (Metric) and U. S. Customary units, with diameter of bolts and flange bolt hole expressed in inch units. This standard is limited to flanges made from cast or forged materials and blind flanges made from cast, forged, or plate materials.