This standard specifies the flat and convex integral steel pipes with nominal pressure PN of 0.6, 1.0, 1.6, 2.5, 4.0, 6.3, 10.0, 16.0MPa and nominal pressure PN of 2.0, 5.0, 11.0, 15.0, 26.0, 42.0MPa Flange type and size. This standard is applicable to flat and raised surface integral steel pipe flanges with nominal pressure PN0.6~PN42.0MPa.