Petrochemical Nuts And Bolts

The standard refers to the American ASTM or ASME standard with new and unique
technical clauses added, which is suitable for a type of petrochemical
fasteners used in high temperature and high-pressure environments, including
bolts, studs, nuts, etc.

The mechanical properties and materials specified in GB/T3098/8 "Mechanical
Properties of Carbon Steel Fasteners Part VIII Heat-resistant Threaded
Connections" are suitable for fasteners that can withstand high temperature,
alternating loads, and to a greater extent. Be sure to tighten the axial force.

High temperature and high-pressure petrochemical fasteners - commodity
fasteners and special fasteners

1. Common Commodity wind energy fasteners:
●The type and size of hexagon head bolts meet the requirements of GB/T5782, A
and B grades. The mechanical properties of these petrochemical fasteners refer
to the performance grades of carbon steel bolts according to GB/T3098/1
standard: A2-50, A4-50, A2-70, A4-70;

●The nut type conforms to GB/T6170 I-type nut and special nut (pipe flange
nut). Its mechanical properties refer to the performance grades of carbon steel
according to the GB/T3098/2 standard: grades 6 and 8; the performance grades of
stainless steel nuts of GB/T3098/15 are A2-50, A4-50, A2-70, A4-70 ;

2. Special Petrochemical Fasteners:
●In order to be suitable for the conditions of high-temperature resistance,
low-temperature resistance, and environmental corrosion resistance, formulate
suitable special fasteners, such as full-threaded studs for pipe flanges, in
accordance with the provisions of GB/T901. The dimensions of hexagon head bolts
and nuts shall be carried out according to national standards.

●Selected materials (grades) include medium carbon alloy steels: 35CrMo
(applicable temperature +100-525℃); 25Cr2MoV (applicable temperature>-20-
-575℃); 42 CrMo (applicable temperature +100-525℃). The strength is between
690~890Mpa, that is to say, the medium carbon alloy steel is tempered at high
temperature (550℃<=tempering temperature<=600℃) to obtain comprehensive
mechanical properties to meet the service of high-temperature environment.

●Stainless steel materials selected are: 0Cr18Mi9 (applicable temperature
-196--800 ℃); 0Cr17Mi12Mo2 (applicable temperature +196--800 ℃); the strength
of stainless steel material obtained by solution treatment is between
690~890Mpa, and the performance level is A2- 70 A4-50 A4-80 grade.

●Using American standards, using stainless steel grades and materials: ASTM
A193 B8 CL.2 (for temperature +196-525℃); A193 B8M CL.2 (for temperature +196-
525℃); A453660 (for temperature +29- 525℃); also includes A320L7 suitable for
low temperature and high-pressure environment (applicable temperature -100℃).

●Special grade nut material (grade) can choose medium carbon alloy steel:
30CrMo, 35CrMo; guaranteed load

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