JB/T 1308.8-1999 This standard is a revision of JB 1315-73 "Pg (2500kgf/cm2) inner and outer nut types, dimensions and technical requirements". This standard specifies the types, dimensions and technical requirements of inner and outer nuts for ultra-high pressure valves. This standard is applicable to inner and outer nuts for neutral media such as ethylene and polyethylene with a nominal pressure of 250MPa. This standard was first published on 2011-03-17. JB/T 1308.8-1999 PN250a inner and outer nut types, dimensions and technical requirements JB/T1308.8-1999 standard download decompression password: www.bzxz.net

1C.S 23.060
Machinery Industry Standard of the People's Republic of China
JB/T1308.1-1308,21-1999
PN250MPa ultrahigh pressure valves and fittings
Technical conditions
Specifcations for PN 2S0 MPa ultrahigh pressure valves and fittings1999-07-12Releasedbzxz.net
National Machinery Industry Bureau
2000-01-01Implementation
Machinery Industry Standard of the People's Republic of China
PN25UMPa inner and outer nuts
Type, dimensions and specifications of PN2soMPairmcraudans nut
The standard defines the type, dimensions and technical requirements of inner and outer nuts for ultrahigh pressure valves. JB13X-19
Find 131573
This standard is applicable to the nominal pressure HN25UMPa of ethylene and other media: 2 Reference standards
The following standards contain provisions that are referenced in this standard and constitute the additional provisions of this paragraph: This standard is weak tonnage, and the versions shown are all effective. All standards will be revised. The parties using this standard shall discuss the use of the following new versions and functions, G6—18
GB197198]
GBT1804.-1992
CHT3077J986
Effective business cattle size (Beijing diameter 0
Back through end effective tolerance and matching (diameter 1-355m) tolerance Dimension tolerance
Technical conditions for structural steel of joint enterprises
JE 1308.2-1999PN250MPa valves, pipes and fasteners Technical conditions 3 Structural types and dimensions
3.1 The type of internal and external frequency mother or the marking according to Figure 1. 30
Approved by the State Machinery Industry Bureau on July 12, 1999 G
2000-01-01 3.2 The size of the inner and outer nut shall be in accordance with the provisions of the old! The nominal diameter is as follows: M20 × 16g, M24 × 2.0, M33 × 2-h2, M48 × 2.6g, technical requirements: light code: M × 1 ±-GF, Mi4x1.5611, M20 × 1.5 ±-6H, M33 × 2 STT, JB/T1398.8—1999, inner and outer screw materials: 35CrM0A, technical requirements: GB/T307? standard is 4.2 After heat treatment, the hardness is HB = 248-302, x
4.3 The thread size is in accordance with the provisions of GBT16, and the thread is in accordance with the 6H grade specified in GB16. 4.4 The thread surface should not have cracks, pits and other defects that affect the strength, and the first incomplete effect should be removed. 4.5 The machine size tolerances that are not specified are in accordance with the provisions of GBT1804. 4.6 The thread part should be taken into account to prevent damage. 4, Other technical requirements are in accordance with the provisions of JB/T1308.2. 5 Marking example
Internal and external nut with a nominal diameter of 15mm:
Internal and external DN15JB/308.8
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