Reference table for common flange bolts

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Nominal diameter, flange thickness, bolt standard, number of bolts, sets, remarks: DN15 – 14, M12X50, 4X2, 8; DN20 – 14, M12X50, 4X2, 8; DN25 – 14, M12X50, 4X2, 8; DN32 – 16, M16X60, 4X2, 8. Flanges, valves, and bolts at 1.6 MPa pressure: 16, M16X60, 4X2, 8; DN50 – 16, M16X60, 4X2, 8; DN65 – 18, M16X60, 4X2, 8; DN80 – 20, M16X70, 8X2, 16; DN100 – 20, M16X70, 8X2, 16; DN125 – 22, M16X80, 8X2, 16; DN150 – 24, M20X80, 8X2, 16; DN200 – 26, M20X80, 12X2, 24; DN250 – 30, M22X90, 12X2, 24; DN300 – 30, M22X90, 12X2, 24; DN350 – 34, M22X100, 16X2, 32; DN400 – 36, M27X110, 16X2, 32; DN450 – 40, M27X120, 20X2, 40; DN500 – 44, M30X130, 20X2, 40. Note: This does not apply to wafer-type butterfly valves. If a double-ended screw is used, the length should be increased by 10–30 mm depending on the size and length of the bolt. 　 Standards for 2.5MPa flanges, valves, and associated bolts: Nominal diameter, Flange thickness, Bolt standard, Number of bolts, Sets, Remarks. DN15: 16, M12X50, 4X2, 8; DN20: 16, M12X50, 4X2, 8; DN25: 16, M12X50, 4X2, 8; DN32: 18, M16X60, 4X2, 8; DN40: 18, M16X60, 4X2, 8; DN50: 20, M16X60, 4X2, 8; DN65: 22, M16X70, 8X2, 16; DN80: 22, M16X70, 8X2, 16; DN100: 24, M20X80, 8X2, 16; DN125: 28, M22X90, 8X2, 16; DN150: 30, M22X90, 8X2, 16; DN200: 34, M22X100, 12X2, 24; DN250: 36, M27X110, 12X2, 24; DN300: 40, M27X120, 16X2, 32; DN350: 44, M30X130, 16X2, 32; DN400: 48, M30X140, 16X2, 32; DN450: 50, M30X150, 20X2, 40; DN500: 52, M36X150, 20X2, 40. Note: This does not apply to wafer-type butterfly valves. If a double-ended screw is used, the length should be increased by 10–30 mm depending on the size and length of the bolt.