National Standard of the People's Republic of China
Mechanical properties of fasteners Nuts made of stainiess steelGB/T3098.15—2000
Approved and issued by: State Administration of Quality and Technical SupervisionDate of issuance: September 26, 2000
Effective date: February 1, 2001
142—1
This standard is equivalent to the international standard ISO3506-2:1997 "Mechanical properties of corrosion resistant stainless steel fasteners Part 2: Nuts". The general title of GB/T3098 is: "Mechanical properties of fasteners", which includes the following parts:
GB/T 3098.1—2000
Bolts, screws and studs
GB/T 3098.2--2000
Coarse pitch thread
-GB/T 3098.3--2000
bZxz.netSet screws
--GB/T 3098.4--2000
Female fine pitch thread
--GB/T 3098.5—2000
Tapping screws
-GB/T 3098.6—2000
Stainless steel bolts, screws and studs
GB/T 3098.7 --2000
Screws
GB/T 3098.8—-1992
Heat-treatment threaded connection
GB/T3098.9—1993
Reinforced rectangular steel hexagonal lock nuts
Mechanical properties of fasteners
Mechanical properties of fasteners
Mechanical properties of fasteners
Mechanical properties of fasteners
Mechanical properties of fasteners
Mechanical properties of fasteners
Mechanical properties of fasteners
Mechanical properties of fasteners
GB/T 3098.10—1993
Mechanical properties of fasteners
Bolts, screws, studs and nuts made of non-ferrous metals - GB/T 3098.11—1995
Self-drilling and self-tapping screws
GB/T 3098.12-1996
Nut cone proof load test
GB/T 3098.13—1996
Mechanical properties of fasteners
Mechanical properties of fasteners
Mechanical properties of fasteners
Torque test and breaking torque of bolts and screws 10mm
GB/T 3098.14-2000
Nut expansion test
GB/T 3098.15—2000
Stainless steel nuts
-GB/T 3098.16—2000
Stainless steel set screws
-—GB/T 3098.17--2000
Nominal diameter 1～
Mechanical properties of fasteners
Mechanical properties of fasteners
Mechanical properties of fasteners
Mechanical properties of fasteners
Preload test for hydrogen embrittlement
Parallel bearing surface method
This standard does not adopt Annex G of ISO 3506-2. Its content has been listed in the referenced standard (Chapter 2).
This standard is GB/T 3098.6-1986 is a revised version. The main changes are as follows:
a) Only the performance of nuts is specified, and the standard name is also modified accordingly; b) Stainless steel bolts, screws and studs and set screws are specified by GB/T3098.6 and GB/T3098.16 respectively; c) Only the mechanical properties tested at an ambient temperature of 15-25°C are specified. The properties may be different at higher or lower temperatures (Chapter 1);
d) The minimum thread diameter (1.6mm) is cancelled in the scope of application (Chapter 1);
e) Add "Corrosion resistance and oxidation resistance and mechanical properties for high temperature or sub-zero use must be agreed upon by the user and the manufacturer for each special occasion." (Chapter 1); f) Add "All austenitic stainless steel fasteners are usually non-magnetic in the annealed state" (Chapter 1); g) Add " A3", "As" group and "C1-110" grade and "low carbon stainless steel with a carbon content of less than 0.03% can be marked *L', such as A4L80" (Figure 1);
h) Adjust the content of some elements in the material (Table 1); i) Supplement and adjust the hardness of martensitic and ferritic steel nuts (Table 3);
j) Add "If there is a dispute, the Vickers hardness test (HV) shall be used as the basis for acceptance" for the hardness test (Article 6.1); k) Add the provisions of "packaging identification" and "surface finishing" (Articles 3.2.2 and 3.3);
1) Add Appendix A to explain the categories and groups of stainless steel; m) Cancel Table C1 in Appendix C of the old standard;
n) Add Appendix D mechanical properties at high temperature and applicability at low temperature, Appendix E austenite, intergranular corrosion of Group A2 (18/8 steel) and Appendix F magnetic properties of austenitic stainless steel. This standard shall replace the relevant parts of GB/T3098.6-1986 from the date of implementation.
Appendix A to Appendix F of this standard are all informative appendices. This standard was proposed by the State Bureau of Machinery Industry. This standard is under the jurisdiction of the National Technical Committee for Standardization of Fasteners. This standard is under the responsibility of the Mechanical Science Research Institute, and the China Aerospace Standardization Institute participated in the drafting.
This standard is interpreted by the Secretariat of the National Technical Committee for Standardization of Fasteners.
ISO Foreword
ISO (International Organization for Standardization) is a worldwide joint organization of national standard bodies (ISO member bodies) of various countries. The formulation of international standards is usually carried out through ISO's various technical committees. Each member body can also participate in the committee if it is interested in the project carried out by a technical committee. Governmental and non-governmental international organizations related to ISO can also participate in this work. ISO has close ties with the International Electrotechnical Commission (IEC) in the field of electrotechnical standardization. Draft international standards adopted by technical committees are circulated to all member bodies for voting. The formal publication of international standards requires at least 75% of the member bodies to vote in favor.
International Standard ISO3506-2 was developed by ISO/TC2 Technical Committee for Fasteners SC1 Subcommittee on Mechanical Properties of Fasteners. This standard, the first edition, together with ISO3506-1 and ISO3006-3, amends and supplements ISO3506:1979, and is a technical revision. ISO3506 is generally called "Mechanical Properties of Corrosion Resistant Stainless Steel Fasteners" and includes the following parts:
-Part 1: Bolts, Screws and Studs Part 2: Nuts
-Part 5: Set Screws and Similar Fasteners Not Under Tensile Stress
Appendix A to Appendix G of this standard are informative appendices. ISO Introduction
In the development of this standard, special attention was paid to fundamentally giving the various characteristics of stainless steel fasteners compared with carbon steel and low alloy steel fasteners. Ferritic and austenitic stainless steels can only be strengthened by cold working, so quenching and tempering cannot be used. These characteristics are recognized in the development of performance grades and test procedures for mechanical properties. 14-2-3
1 Scope
This standard specifies the mechanical properties of nuts made of austenitic, martensitic and ferritic corrosion-resistant stainless steel when tested at an ambient temperature of 15 to 25°C. The properties may be different at higher or lower temperatures.
This standard applies to nuts:
Nominal thread diameter D≤39mm;
Ordinary thread in accordance with GB/T192;
Meet the diameter and pitch combination specified in (B/T193; Meet the basic dimensions specified in GB/T196;
Meet the tolerances specified in (B/T197;
Any shape;
The width across flats conforms to GB/T3104;
Nominal height ≥0.5D.
This standard specifies the following performance requirements:
Locking performance;
Weldability.
Corrosion resistance and oxidation resistance under special circumstances. The purpose of this standard is to classify the performance of stainless steel fasteners. Some materials can be used in air at temperatures of -200°C, while some materials can be used in air at temperatures of +800°C. Information on the influence of temperature on mechanical properties is given in Appendix D (Informative Appendix). Corrosion resistance, oxidation resistance and mechanical properties for high temperature or sub-zero use must be agreed upon by the user and the manufacturer for each specific occasion. Appendix E (Informative Appendix) gives information on the influence of carbon content on intergranular corrosion under high temperature conditions. All austenitic stainless steel fasteners are usually non-magnetic in the annealed state; after cold working, some magnetism may be apparent, see Appendix F (Informative Appendix).
2 Referenced Standards
The provisions contained in the following standards constitute the provisions of this standard through reference in this standard. When this standard is published, the versions shown are valid. All standards will be revised, and parties using this standard should explore the possibility of using the latest version of the following standards. GB/T 192-1981
GB/T 193--1981
(diameter 1~600mm）
GB/T 1961981
(1-600mm)
GB/T 197--1981
diameter 1~355mm）
GB/T 230--1991
Ordinary thread
Basic tooth profile
Diameter and pitch series
Through thread
Ordinary thread
Ordinary thread
Basic size (diameter
Tolerance and fit (diameter
Metal Rockwell hardness test method
4Metal Brinell hardness test method
GB/T 231--1984
GB/T 3098.2-2000 Mechanical properties of fasteners Nut coarse thread (idtISO8982:1992)
GB/T3098.4-2000 Mechanical properties of fasteners Nut
Fine thread (idt ISO898~6:1994) 14 --2- 4
GB/T 3104-1982
Hexagonal product width across flats
Fastener
degrees (eqv ISO) 272:1982)
GB4340.1-1999 Vickers hardness test for metals Part 1
: Test method (eqvISO65071:1997)IS)683-13:1986 Heat-treatable steels, alloy steels and free-cutting steels Part 13: Wrought stainless steels
ISO 3651-1:1976
(A revised version will be issued) Determination of resistance to intergranular corrosion of stainless steels Part 1: Corrosion test for austenitic and ferritic-austenitic (duplex) stainless steels to measure mass loss in nitric acid (intergranular corrosion test)
ISO 3651-2: 1976
(Revision to be issued) Determination of resistance to intergranular corrosion of stainless steels Part 2: Corrosion test of ferritic, austenitic and ferritic-austenitic (duplex) stainless steels in sulphuric acid medium
ISC) 4954:1993 Steels for cold heading and cold extrusion 3 Marking, marking and surface finishing
3.1 Marking
The marking system for stainless steel groups and property grades for nuts is shown in Figure 1. The material marking consists of two parts separated by a dash. Each part marks the steel group, and the second part marks the property grade. The steel group (first part) marking consists of a letter and a number, the letter indicates the type of steel, and the number indicates the chemical composition of the steel range - austenitic steel; C - martensitic steel; F - martensitic steel. Among them: A - ferrite steel.
Property grade (part 2) marking: For (type 1) nuts with m ≥ 0.8D, it consists of two digits and indicates 1/10 of the guaranteed load stress; for (thin) nuts with height 0.5D ≤ m < 0.8D, it consists of three digits, the first digit indicates a nut with reduced load capacity, and the last two digits indicate 1/10 of the guaranteed load stress. Note: For the description of type 1 nuts, see Appendix A of GB/T3098.2. Example:
1) A2-70 means:
austenitic steel, cold worked, minimum guaranteed stress (type 1 nut) is 700N/mm2 (700MPa);
2) C4-70 means:
martensitic steel, quenched and tempered, minimum guaranteed stress (type 1 nut) is 700N/mm2 (700MPa);
3) A2-035 means:
austenitic steel, cold worked, minimum guaranteed stress (thin nut) is 350N/mm2 (350MPa).
3.2 Marking
Only when all technical requirements of this standard are met can the nut products be marked and/or labeled according to the marking system of Article 3.1. 3.2.1 Nuts
Marking is mandatory for nuts with a nominal thread diameter D ≥ 5 mm. The steel group and property grade shall be marked according to Figures 1 and 2 in 3.1. The manufacturer's identification mark shall also be provided as far as technically feasible. It may be marked on only one bearing surface of the nut and only on one bearing surface of the nut. Steel type 1)
Steel group 1)
Property grade
Type 1 nut
Thin nut
Austenite
Cold worked
High strength
025035055025
Pinghuojing
Martensite
Quenched and
Zhehuojing
Stainless steel group and property grade marking system diagram for nut products!
1) The classification of the types and groups of steel in the figure is explained in Appendix A (indicative appendix), and the chemical composition is as specified in Table 1. 2) Low carbon stainless steel with a carbon content of less than 0.03% can be marked with "L\", such as A41-80. Y2
1-type nut
A4L-8
A4L-80
A pair of side width
Nut marking
1-Manufacturer's identification mark; 2-Steel group; 3-Performance level 1-025
C1-025
Thin nut
(a) Material mark and manufacturer's identification mark; (6) Optional carved sandalwood mark (only applicable to A2 and A4 groups) Note: For the marking of left-hand thread, see GB/T3098.2. Ferrite
Cold working
14-2- 5
Can be [concave. In addition, marking on the side of the nut is also allowed. When groove marking (Figure 2) is used, the performance grade can be omitted only for grades 50 or 025.
3.2.2 Packaging marking
For all packages of all specifications, it is mandatory to mark the manufacturer's trademark or identification mark and the steel group and performance grade. 3.3 Surface finishing
Unless otherwise specified, fasteners complying with this standard shall be cleaned and bright treated. Passivation treatment is recommended to maximize corrosion resistance.
Austenite
Martensite
Ferrozen
0.09~0.15
0.17-0.2 5
The stainless steel materials suitable for fasteners produced in accordance with this standard are given in Table 1.
Unless otherwise agreed between the supplier and the purchaser, the chemical composition shall be within the range specified for the steel group and selected by the manufacturer.
In cases where there is a tendency for intergranular corrosion, it is recommended to test in accordance with the provisions of ISO36511
or ISO36512. In this case, it is recommended to use stabilized A3 and A5, or 42 and A4 stainless steels with a carbon content not exceeding 0.03%.
Stainless steel groups and chemical composition
Chemical composition\%
10.15-0.35
0.15-0.35
16 ~19
15 ~20
16 - 18.5
16 ~18
12 ~14
15～18
10 ~ 15
10.5～14
1.75 ~2.25
2)3),4)
7),8)
8),10)
9),10)
2),10)
11),12)
1. The categories and groups of stainless steel, as well as the description of their characteristics and applications, are given in Appendix A. 2.Examples of stainless steels standardized by ISO683-13 and ISO4954 are given in Appendix B (Indicative Appendix) and Appendix C (Indicative Appendix) respectively. 1) All values are maximum values except those indicated. 2) Sulfur may be replaced by selenium.
3) If the content is less than 8%, the minimum manganese content must be 5%. 4) When the tantalum content is greater than 8%, there is no restriction on the minimum copper content. 5) The zircon content may appear in the manufacturer's specifications. However, for certain applications, if it is necessary to limit the molybdenum content, it must be indicated by the user in the order. 6) The molybdenum content may appear in the manufacturer's specifications. 7) If the chromium content is less than 17%, the minimum tantalum content should be 12%. 8) For austenitic stainless steels with a maximum carbon content of 0.03%, the nitrogen content may be up to 0.22%. 9) In order to stabilize the organization, the titanium content should be ≥5×C%~0.8% and should be appropriately marked according to this table, or the saw and (or) silver content should be ≥10×C%~1.0% and should be appropriately marked according to this table.
10) For products with larger diameters, in order to achieve the specified mechanical properties, the manufacturer's instructions may have a higher carbon content, but it should not exceed 0.12% for austenitic steel.
11) The titanium content may be ≥5×C%~0.8%. 12) The sharp content may be ≥10×C%~1.0%. 5 Mechanical properties
The mechanical properties of nuts produced according to this standard shall comply with the provisions of Table 2 or Table 3.
The mechanical properties specified in this chapter are applicable to acceptance inspection and the following tests shall be carried out:
-Hardness test as per 6.1 (only applicable to groups C1, C3 and C4, quenched and tempered):
~Proof load test as per 6.2.
Austenitic
A2, A3,
Type 1 nuts
Performance level
Mechanical properties of austenitic steel nuts
Thread diameter range D
Thin nuts
(0.5D≤m<0.8D)
Guaranteed stress S,, N/mm
Type 1 nuts
Thin nuts
(0.5Dm<0.8D)
A4, A5
1) For fasteners with nominal thread diameter D》24mm, the mechanical properties shall be agreed upon by the supply and demand parties and may be marked according to the groups and performance levels given in this table. Table 3
Martensite
Ferrite
Type 1 nut
Performance grade
Mechanical properties of martensitic and ferritic steel nuts Guaranteed stress S, N/mm2
Thin nut
Type 1 nut
(m≥0.81)/(0.5D≤m<0.8D) [(n≥0.8D)/1(0.535m<0.8D)
1) Quenching and annealing, the minimum tempering temperature is 275℃. 2) Thread nominal diameter D≤24mms
Test method
Hardness HB, HRC or HV
Hardness test shall be carried out in accordance with the provisions of GB/T231 (HB), GB/T230 (HRC) or GB/T 4340.1 (HV). In case of dispute, the Vickers hardness test (HV) shall be used as the basis for acceptance. The test procedure shall be in accordance with GB/T3098.2 and GB/T3098.4. The hardness shall comply with the provisions of Table 3.
6.2 Proof load
The test procedure and judgment shall be in accordance with GB/T3098.2 or GB/T3098.4.
Appendix A
(Indicative Appendix)
Description of stainless steel categories and groups
A1 General
Steel used in: GB/T 3098.6, GB/T 3098.15 and GB/T3098.16, involving the following steel types: Austenitic steel: A1~AS
Martensitic steel: C1C4
Ferritic steel: F1
147~-209
209-314
228~323
147209
209~314
128~209
171~271
20 ~34
This appendix describes the properties of the above steels. HV
155~220
220~330
350-440
240-340
155~220
220~330
135~220
180~285
This appendix also gives some information on non-standardized FA group steels. This type of steel has a martensitic-austenitic structure. A2A type steel (austenitic structure)
Five basic groups A1 to A5 are specified in GB/T 3098.6, GB/T 3098.15 and GB/T3098.16. They cannot be annealed and are usually non-magnetic. To reduce the sensitivity to work hardening, copper can be added to A1 to A5 steels as specified in Table 1. For metastable A2 and A4 steels, the following applies:
Chromium oxide improves the corrosion resistance of steels. Low carbon content is extremely important for metastable steels. Because chromium has a high affinity for carbon, chromium carbides can replace chromium oxide, which is more easily formed at high temperatures (Annex F). For stable A3 and A5 steels, the following applies:
Ti, Nb or Ta elements affect the presence of carbon, causing chromium oxide to reach its maximum content.
For marine or similar use environments, Cr and Ni contents of about 20% each and Ma content of 4.5% to 6.5% are required. When there is a high tendency to corrosion, experts should be consulted. 14-2-7
A2.1Al steels
A1 steels are specially designed for machining. This group of steels has a high sulfur content and therefore has a lower corrosion resistance than steels with corresponding standard sulfur content.
A2.2A2 group steel
A2 group steel is the most widely used stainless steel, used in kitchen equipment and chemical equipment. This group of steel is not suitable for non-oxidizing acids and non-nitrogen media, such as swimming pools and seawater.
A2.3A3 group steel
A3 group steel is a stable "stainless steel", the performance of the steel is the same as A2 group steel.
A2.4A4 group steel
A4 group steel is "acid-resistant steel", containing Mo elements, which can provide quite good corrosion resistance. A4 is usually used in the chemical fiber industry. This group of steel was developed for boiling sulfuric acid (hence the name "acid-resistant"), and is also suitable to a certain extent for chloride-containing occasions. A4 is also commonly used in the food industry and shipbuilding industry.
A2.5A5 group steel
A5 group steel is a stable "acid-resistant steel", the performance of the steel is the same as A4 group.
A3F steel (ferritic structure)
F1 group ferritic steel is adopted in GB/T3098.6 and GB/T3098.15. F1 group steel cannot be hardened normally, and should not be quenched even if it is possible in some cases. F1 group steel is magnetic. A3.1F1 group steel
F1 group steel is usually used for simpler devices. The device should avoid ultra-pure ferrite with very low C and N content. If necessary, F1 group steel can replace A2 and A3 group steel. Usually has a higher chromium content. A4C steel (martensitic structure)
C1, C3 and C4 three groups of martensitic steel are adopted in GB/T 3098.6 and GB/T3098.15. They can be quenched to extremely high strength and are magnetic.
A4.1 C1 steel group
The corrosion resistance of C1 steel group is limited and it is used for turbines, pumps and knives. A4.2C3 steel group
The corrosion resistance of C3 steel group is better than that of C1 steel, but it is still limited and it is used for pumps and valves.
A4.3C4 steel group
The corrosion resistance of C4 steel group is limited and it is used for machining materials. Other aspects are similar to C1 steel group.
A5FA steel (ferrite-austenite structure)FA steel is specified in GB/T3098.6, GB/T3098.15 and GB/T3098.16 has not yet been adopted, but it is very likely to be adopted in the future. This type of steel is the so-called dual phase steel. The originally developed FA steels had some defects, which have been overcome in the more recently developed steels. FA steels have better properties than A4 and A5 steels, especially strength, and they also have excellent resistance to pitting and crevice corrosion.
Examples of compositions are given in Table A1.
Table A1 Ferrite-austenite steel-
Chemical composition
Chemical composition, %
Ferrite-austenite
Appendix B
(Suggestive Appendix)
Technical conditions for stainless steel composition
(Extracted from ISO683-13:1986)
Chemical composition 2), %
1.01.00.0400.030max
1.01.00.0400.030max
Ferritic steel
16.0 ~ 18.0
16.0~18.0
16.0 ~18.00.90~1.30
17.0~ 19.01.75~ 2.50
F10.025max)1.01.00.0400.030max0.025maxMartensitic steel
3T0.09~0.151.0|1.00.0400.030max0.08~0.15 |1.0|1.50.0600.15~0.35[0.16~0.25 1.0 , 1.0 [0.040
[0.19~0.17|1.0|1.50.0600.15~0.340.14~0.23|1.01.00.040
10.26 ~0.351.01.00.040
-2—8
0.030tmax
11.5~13.5
12.0 ~14.0 | 0.60max7)
12.0~14.0
15.5~17.50.60max
15.0~17.5
12.0~14.0
7×%C≤1. 10
Fastener group
Special mark4)
19N 1 0.030max
11.02.00.045
2.0 /0.0600.15 ~ 0.35
10.030max
1.02.00.045
1.012.00.045
1 2.0.(045
1.02.00.045
Austenitic steel
17.0-19.0
117.0 ~19.0 i
17.0 19.0
17.0~19.0
ferritic steel
17. 0 ~ 19.0
16.5~18.5
16.5- 18.52.0 ~2.5
16.5~18.5
16.5 ~18.5 / 2.0 ~2.5
16.5~18.5
40.12~0.22
0.0450.030mx
1.0|2.00.0450.030max
0.12~0.22
16.5~ 18.5 | | tt |
11.0 ~ 14.c
10.5 -13.4
11.0-14.0
10×%C
11.0~14.c
10.5 ~13.5
11.5~ 14.s
Fastener Group
Special Mark 4
1) Type number is determined and will change when the relevant international standard is formulated. 2) Elements not listed in this table cannot be added without the user's consent, unless refining is required. Reasonable precautions should be taken to prevent the addition of certain elements (from scrap or other metals mixed in the manufacturing process) because these elements will affect the hardenability, mechanical properties and performance of the material. 3) Package! Content depends on content.
4) Not the content of ISO 683-13.
5) ((+ N) max is 0.040%
6) 8×(C+N)(Nb+ Ti) ≤0.80%
7) After inquiry and order signing, steel with Mo content of 0.20% to 0.60% may be provided. 8) Excellent resistance to intergranular corrosion.
9) Stability steel.
10) The manufacturer may choose to add up to a maximum of 0.70% molybdenum 11) For semi-finished products for the manufacture of seamless steel pipes, the nickel content may be increased by 0.5% Appendix C
(Indicative Appendix)
Stainless steel for cold heading and cold extrusion
(Extracted from ISO4954:1993)
Type of steel (designation\)
Ferritic steel
X3Cr17E
X6Cr17E
73[ X6CrMu17 1E
X6CrTi12E
X6CrNb12E
1S0 4954:1979
max nax max
0.041.001.000.0400.03016.0~18.00.08
1.00|1.000.0400.03016.0~18.0 points 2), %
1.001.00|0.0400.03016.018.00.90~1.301.000.0400.03010.5~12.5
1.00 | 1.00 |0.040|0.030|10.5 ~12.51.0
Ti: 6×%C≤1.0
Nb: 6× %C≤1.0
Fastener 3)
Group mark
14—2—
Type of steel
(mark)
Martensitic steel
76X12Cr13E
77x19CrNi16 2E
Austenitic steel
78X2CrNi18 10E
79X5CrNi189F
80X10CrNi189E
81xSCrNi1812E
82X6CrN18 16E
83X6CrNITi18 10E
84X5CtNiMo17122E
85X6CrNiMoTi17 12 2E
86X2CrNiMo17 13 3E
87x2CrNiMoN17133E
88X3CrNiCu18 9 3E
1SO 4954:1979
points 3), %
chemical composition
p.900.151.001.000.040|0.030/11.513.5D10
0.14~0.23 1.001.000.040/0.03015.0~17.51.00|2.000.0450.03017.0~19.00.030
1.0 02.000.0450.03017.0~19.0
1.002.000.0450.03017.0~19.0
1.002.0 00.045|0.03017.0~19.002.000.045/0.03015.0~17.0
1.002.000.0450.030 17.019.0
1.00|2.000.0450.030|16.5~18.50.0450.030|16.5~18.5
1 2.0 ~2.5
1.00|2.00|0.045/0.030|16.5~18.5 2.5~3.0≤0.030
1.002.00|0.0450.030|16.5~18.5≤0.030
1.002.000.0450.030|17.0~19.0N0.04
8.0 ~11.0
11.0 ~13.0
17.0~19.0
10.5~13.5
11.0~14.0
11.5~14.5
11.5~14.5
Ti: 5× %C≤0.80
Tr: 5×%C≤0.80
N: 0.120.22
Cu: 3.00~4.00
Fastener 3)
Group mark
1 ) The symbols in the first column are sequential numbers. The symbols in the second column are based on the marking system recommended by ISO/TC17/SC2. The symbols in the third column indicate the numbers used in ISO4954:1979 (revised in 1993) and have been abolished. Yuanhao not listed in this table cannot be added without the user's consent unless refining is required. Reasonable precautions should be taken to prevent the addition of certain elements (from scrap or other metals mixed in during the manufacturing process) because these Element disorder will affect the hardenability, mechanical properties and performance of the material. 3) It is not included in ISO4954.
4) It has excellent resistance to intergranular corrosion.
Appendix D
(Informative Appendix)
Mechanical properties at high temperatures and applicability at low temperatures Note: If the bolts, screws or studs are calculated to be suitable, then The matching nut will also meet the conditions. Therefore, in the case of application at high or low temperatures, the mechanical properties of the bolt, screw or stud will be considered to be fully considered.
The yield point at high temperature, or the specified Non-proportional elongation stress 0.2D1
The values given in this appendix are for guidance only. The user should be aware that the actual chemical composition and properties, the loads and the environment in which the fastener is installed may vary greatly. If the loads are cyclic, heavy or there is a high likelihood of stress corrosion at elevated temperatures, the user should consult the manufacturer.
Service point at elevated temperatures. and non-proportional elongation The length should be the ratio of the value of α0.2 to the value at room temperature (expressed in %), see Table D1. Table D1
A2, A4
and p0. 2
0,
[email protected],%
+100℃
+200 ℃
Note: Only applicable to performance grades 70 and 80.14-2-10
+300℃
Applicability at low temperatures
Stainless steel bolts, Suitability of screws and studs, see table D2
Suitability of stainless steel bolts, screws and studs at low temperatures (austenitic steels only)
Lower temperature for continuous operation Limit A2
Bolts and screws)
-60℃
1) Since the alloying element Mo reduces the stability of austenite, if the fastener is highly deformed during the manufacturing process, The critical temperature can be adjusted to a higher value.
Appendix E
(Suggestive Appendix)
Time-temperature diagram of intergranular corrosion of austenitic steel, A2 group (18/8 steel)
Figure E1 gives Austenitic stainless steels with different carbon contents, group A2 (18/8 steel), temperature range 550-~925°C. Approximate time before intergranular corrosion tendency occurs.
Appendix F||tt ||(Appendix to the Tips)
Magnetism of austenitic stainless steel
Time, min
It is only possible to be completely non-magnetic in a vacuum state. Magnetic permeability of materials in a magnetic field The measurement is relative to the material's magnetic permeability, μ, in a vacuum. If μ, is close to 1, the material has low magnetic permeability. For example:
A2: μ,~1.8||tt ||Generally, all austenitic stainless steel fasteners are non-magnetic: after cold working, some magnetism may be evident. The characteristics of each material's ability to be magnetized also apply to stainless steel. A4: μl~1.015
A4L: μl~1.005
Fl: μt~s
14—2—11μt~s
14—2—11μt~s
14—2—11
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