The First Machinery Industry Department of the People's Republic of China Standard Welded Branch Pipe Fittings JB977-77 Replaces JB977-87 This standard applies to branch pipe fittings in oil-based pipeline systems, with a nominal pressure of 320kgf/cm2 and a working temperature of -25 to 80℃. Marking example: Branch pipe fittings with a pipe outer diameter of 28mm, and a fitting body of 28JB977-77 Issued by the First Machinery Industry Department of the People's Republic of China Proposed by the Standardization Research Institute of the First Machinery Industry Department Implementation on May 1, 1977 Drafted by Jinan Foundry and Forging Machinery Research Institute, etc. 341 JB977-77bzxz.net Standard No. Technical conditions are in accordance with the provisions of JB1003-77. 1 JB98077 JB981—77 GB1235- O-ring Rubber-4 M12×1.25 M36×2 M42×2 M52×2 2. The material of the seamless steel pipe is 15, 20 steel, and the precision is ordinary grade. 342 JB997—77 Joint body Tip: This standard content only shows part of the intercepted content of the complete standard. If you need the complete standard, please go to the top to download the complete standard document for free.