HG/T 21573.3-1995 Large diameter nuts HG/T21573.3-1995 Standard download decompression password: www.bzxz.net

Large diameter nuts
HG/T21573.3-95
Subject content and scope of application
This standard specifies the structural dimensions and technical requirements of large diameter nuts for pressure vessel equipment flanges and manhole flange connections. 41
GB3077
GB2106
HG/T21573.1
HG/T21573.2
HG/T21573.4
2 Reference standards
《Technical conditions for high-quality carbon structural steel》
《Technical conditions for alloy structural steel》
《Basic dimensions of ordinary threads》
《Tolerances and fits of ordinary threads》
《Tolerances of fasteners, bolts, screws and nuts》《Steel pressure vessels》|| tt||《Steel Shell and Tube Heat Exchanger》
《Metal Tensile Test Method》bzxZ.net
《Metal Brinell Hardness Test Method》
《Metal Charpy (V-Notch) Impact Test Method》《Steel Chemical Container Material Selection Regulations》《Bolt Hydraulic Tightening Device Series》
《Large Diameter Studs》
《Spherical Washers》
3 Type, Dimension and Weight of Large Diameter Nuts 3.1. R-type Nuts
R-type nuts are round nuts, designed to be used with AR and BR hydraulic tensioners. The structural type is shown in Figure 3.1, and the dimensions and weights are specified in Table 3.1.
3×45°
Figure 3.1 R-type Nuts
Note: The small hole depth of M48~M56 nuts is 8mm. 43
Nut specifications
M100X4
M105×4
M110X4
M115×4
M120X4
M125X4
M130X4
M140X4
Large diameter nut size and weight table
3.2H-type nut
H-type nut is a hexagonal nut, which is only used when manual tightening is considered in the design. The structural type is shown in Figure 3.2, and the size and weight are specified in Table 3.1.
Figure 3.2H-type nut
3.3HI-type nut
HI-type nut is a hexagonal nut with a extraction hole. This type of nut can be used for manual tightening or hydraulic tightening. When hydraulic tightening is adopted, it is matched with AH and BH hydraulic tensioners. The structural type is shown in Figure 3.3. The dimensions and weights are specified in Table 3.1.
Figure 3.3HI-type nut
3.4HR-type nut
HR-type nut is a hexagonal circular combined nut. This type of nut can be used for manual tightening or hydraulic tightening. When hydraulic tightening is adopted, it is matched with AH and BH hydraulic tensioners. The structural type is shown in Figure 3.4. The dimensions and weights are specified in Table 3.1.
Note: The depth of the small hole of M48~M56 nuts is 8mmD
Figure 3.4HR type nuts
Dimension tolerance
The basic dimensions of the thread shall comply with GB196, the tolerance shall comply with 6H specified in GB197, the thread root is round, and the other dimensional tolerances of the nut shall comply with Class A in GB3103.1. 48
Material and manufacturing technical requirements for nuts
5.0.1The material of the nut shall comply with the provisions of GB699 or GB3077, and the heat treatment system and mechanical properties after heat treatment shall comply with the provisions of Table 5.0.1. The mechanical property test specimen shall be cut along the rolling direction from the rough piece after the specified heat treatment, and the test specimen shall be cut at 1/4 of the diameter.
30CrMoA
Material standard
GB3077
Nut specification
M48~M140
M48M140
Heat treatment system
Tensile strength
≥450
≥765
Yield point
≥275
≥355
≥635
Elongation
After the material is heat treated, each nut must be checked for hardness, and its hardness shall comply with the requirements of Table 5.0.2. 5.0.2
30CrMoA
≤170
187~229
187229
Impact energy
5.0.3 The thread surface is not allowed to have cracks, bumps and burrs. The contact surface between the nut and the flange and the spherical surface are not allowed to have groove marks, scratches and other defects.
5.0.4 The surface of the nut must be phosphating treated.
HG/TXX.X-XX
Nut standard number
Marking example and steel stamp marking
Marking method
Nut specification
6.2 Marking example
Nut type
Example 1: A nut with a diameter of 64mm, a pitch of 4mm, a material of 40Mn, and an R type is marked with: HG/T21573.3-95 Nut M64×4-R40MnExample 2: A nut with a diameter of 80mm, a pitch of 4mm, a material of 30CrMoA, and an HR type is marked with: HG/T21573.3-95 Nut M80X4-HR30CrMoA6.3 Steel stamp marking
The manufacturer of the nut should mark the material brand with a steel stamp on the side of the nut. 50
Additional Notes Proposal unit, chief editor unit and main drafters of this standard
Proposal unit:
Equipment Design Technology Center of Ministry of Chemical Industry
China Wuhuan Chemical Engineering Company
Chief editor unit:
Main drafters: Liu Youyi
Wang Ronggui
Yao Peixian
Yao Beiquan
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