Nut marking method

Marking of the nut: name, standard number, nominal diameter × pitch-material-surface treatment

a. Name: use the standard name specified by the national standard, such as nuts.

b. The identification of standard number, pitch, material, and surface treatment is the same as that of screws.

 

Nut-Ministry standard, enterprise standard, foreign standard

Fasteners for HG20613-97 steel pipe flanges (American system)

Fasteners for HG20634-97 steel pipe flanges (European system)

SHJ404-88 Sinopec Standard (Fasteners for pipe flanges)

HGJ75-91 Ministry of Chemical Machinery Standard (nut)

GD0534 Ministry of Water Resources and Electric Power Standard (Thick Hexagon Nut)

GD0535 Ministry of Water Resources and Electric Power Standard (Hexagon Nut)

H17-67 Ministry of Chemical Machinery Standard (nut)

JB2770-79 Ministry of Machinery Standard (Pg160-320kg/cm2 joint nut)

JB2775-79 Ministry of Machinery Standard (Pg160-320kg/cm2 nut)

JB2954-81 Ministry of Machinery Standard (Technical Conditions for Turbine Cover Nuts)

SY15-76 Shanghai Pressure Vessel Factory Standard (High-Pressure Hexagon Nut)

DIN2510/5-74 German standard (nut)

DIN2510/6-74 German standard (long nut)

ASME/ASNIB18.2.2 American Standard (nut)

 

Nut process production

Nuts should be produced by hot forging or cold forging processes, and bar cutting can also be used. Screws and nuts of grade 8S and 8S3 can be produced with any material that can meet their performance requirements and should be heat treated and quenched in a liquid medium. The quenching temperature should be higher than the phase transition temperature of the material and should be tempered at a temperature not lower than 425°C. The chemical composition of the material used for the 8S grade nut is under the requirements of the regulations C<0.20%, P<0.04%, S<0.05%. The nut can be processed without tempering. The nuts of grade 10, grade 12, grade 10S, and grade 10S3 should be heat treated and quenched in a liquid medium. The quenching temperature should be higher than the phase transition temperature of the material and should be tempered at a temperature not lower than 425℃.

When the nut needs to be protected by zinc coating, the buyer shall specify the coating method used:

If the buyer requires hot-dip galvanizing, it should be hot-dip galvanized according to the requirements of ASTMF2329

If the buyer requires mechanical galvanizing, the mechanical galvanizing treatment shall be carried out in accordance with the requirements of grade 55 in ASTM B695.

If the buyer does not specify the zinc coating process, the supplier can perform hot-dip galvanizing according to the requirements of ASTM F2329 or mechanical galvanizing according to the requirements of ASTM F2329 level 55, either.

Hot-dip galvanized nuts should be reamed and threaded, and hot-dip galvanized and then tapped, without coating.

Mechanically galvanized nuts should also be reamed to machine threads, but they should be mechanically galvanized after the thread processing is completed, and the threads have excess plating.