GOST R ISO 3506-1-2009 Mechanical Properties of Corrosion-Resistant Stainless Steel Fasteners. Part 1. Bolts, Screws and Studs
GOST R ISO 3506-1 · General fastener standards
This is an informational translation of a Russian national standard. The Russian original is authoritative.
GOST R ISO 3506-1-2009
Group G30
NATIONAL STANDARD OF THE RUSSIAN FEDERATION
MECHANICAL PROPERTIES OF CORROSION-RESISTANT STAINLESS STEEL FASTENERS
Part 1
Bolts, Screws and Studs
Mechanical properties of corrosion-resistant stainless steel fasteners. Part 1. Bolts, screws and studs
OKS 21.060.10
OKP 16 0000
Effective date 2011-01-01
Foreword
The objectives and principles of standardization in the Russian Federation are established by Federal Law No. 184-FZ of December 27, 2002, “On Technical Regulation,” and the rules for applying national standards of the Russian Federation are established by GOST R 1.0-2004, “Standardization in the Russian Federation. Basic Principles.”
Information about the standard
1 PREPARED by the Federal State Unitary Enterprise “All-Russian Scientific Research Institute for Standardization and Certification in Mechanical Engineering” (VNIINMASH) based on its own authentic Russian translation of the standard specified in item 4
2 SUBMITTED by Technical Committee for Standardization TC 229 “Fasteners”
3 APPROVED AND PUT INTO EFFECT by Order of the Federal Agency for Technical Regulation and Metrology No. 695-st of December 10, 2009
4 This standard is identical to the international standard ISO 3506-1:1997, “Mechanical properties of corrosion-resistant stainless steel fasteners - Part 1: Bolts, screws and studs” (ISO 3506-1:1997 “Mechanical properties of corrosion-resistant stainless steel fasteners - Part 1: Bolts, screws and studs”)
When applying this standard, it is recommended to use, instead of the referenced international standards, the corresponding national standards of the Russian Federation and the interstate standards in effect in that capacity, information on which is given in Additional Annex DA
5 INTRODUCED FOR THE FIRST TIME
Information on amendments to this standard is published in the annually issued information index “National Standards,” and the text of amendments and corrections is published in the monthly issued information indexes “National Standards.” In the event of revision (replacement) or cancellation of this standard, a corresponding notice will be published in the monthly issued information index “National Standards.” The relevant information, notice and texts are also posted in the publicly available information system - on the official website of the Federal Agency for Technical Regulation and Metrology on the Internet
1 Scope
This standard establishes the mechanical properties of bolts, screws and studs made of austenitic, martensitic and ferritic corrosion-resistant stainless steels when tested under ambient temperature conditions from 15 °C to 25 °C. The mechanical properties change with increasing or decreasing temperature.
The standard applies to bolts, screws and studs:
- with a nominal thread diameter up to and including 39 mm;
- with triangular metric thread, with diameter and pitch to ISO 68-1, ISO 261 and ISO 262;
- of any design.
This standard does not apply to bolts, screws and studs with special properties, such as weldability.
This standard does not establish requirements for corrosion resistance or oxidation resistance under special environmental conditions. Some information on materials for special environmental conditions is given in Annex E. Definitions of corrosion and corrosion resistance are in accordance with ISO 8044.
This standard establishes a classification by property class of fasteners made of corrosion-resistant stainless steel. Some of these steels may be used at low temperatures down to minus 200 °C, others at high ambient temperatures up to 800 °C. Information on the effect of temperature on mechanical properties is given in Annex F.
Corrosion resistance, oxidizability and mechanical properties at elevated and reduced temperatures shall be agreed between the manufacturer and the consumer in each specific case. The change in the risk of intergranular corrosion with increasing temperature depending on carbon content is shown in Annex G.
All fasteners made of austenitic stainless steels are non-magnetic under normal conditions; magnetic properties may appear after cold working (see Annex H).
2 Normative references
The following normative standards contain provisions which, through reference in this text, constitute provisions of this standard. For dated normative standards referenced herein, subsequent amendments or revisions of those standards do not apply.
ISO 68-1 ISO general-purpose screw threads. Basic profile. Part 1. Metric screw threads
ISO 261 ISO general-purpose metric screw threads. General plan
ISO 262 ISO general-purpose metric screw threads. Selected sizes for screws, bolts and nuts
ISO 724:1993 ISO general-purpose metric screw threads. Basic dimensions
ISO 898-1:1999 Mechanical properties of fasteners made of carbon steel and alloy steel. Part 1. Bolts, screws and studs
ISO 3651-1 Stainless steels. Determination of resistance to intergranular corrosion. Part 1. Austenitic and ferritic-austenitic (duplex) stainless steels. Corrosion test in nitric acid medium by measurement of loss in mass (Huey test)
ISO 3651-2 Stainless steels. Determination of resistance to intergranular corrosion. Part 2. Ferritic, austenitic and ferritic-austenitic (duplex) stainless steels. Corrosion test in media containing sulfuric acid
ISO 6506:1981 Metallic materials. Hardness test. Determination of Brinell hardness
ISO 6507-1:1997 Metallic materials. Vickers hardness test. Part 1. Test method
ISO 6508:1986 Metallic materials. Hardness test. Determination of Rockwell hardness (scales A, B, C, D, E, F, G, H, K)
ISO 6892 Metallic materials. Tensile testing
ISO 8044 Corrosion of metals and alloys. General terms and definitions
3.1 Designations
The designation system for stainless steel grades and property classes of bolts, screws and studs is given in Figure 1. The material designation consists of two parts separated by a hyphen. The first part designates the steel grade, the second part designates the property class.
Figure 1 - Designation system for stainless steel grades and property classes of bolts, screws and studs
The steel classes classified according to Figure 1 are described in Annex B and defined by chemical composition in Table 2.
Stainless steels with a carbon content not exceeding 0.03% may be additionally marked with the letter L.
Example - A4L-80
The steel grade designation (first part) consists of a letter:
A - austenitic steel; C - martensitic steel; F - ferritic steel,
which designates the steel class, and a digit, which designates the range of limit values of the chemical composition of that steel class.
The property class designation (second part) consists of two digits, which designate 0.1 of the minimum tensile strength.
Designation examples:
1 - austenitic stainless steel, cold-worked, with a tensile strength of not less than 700 N/mm² (700 MPa) - A2-70.
2 - martensitic steel, quenched and tempered, with a tensile strength of not less than 700 N/mm² (700 MPa) - C4-70.
3.2 Marking
Fasteners meeting all the requirements of this standard shall be marked and (or) designated in accordance with 3.1.
3.2.1 Bolts and screws
All hexagon head bolts and screws and hex socket head screws with a nominal thread diameter of 5 mm shall have clear marking in accordance with 3.1, Figures 1 and 2. Marking is mandatory and shall include the steel grade and property class, as well as the manufacturer’s trademark. Other types of bolts and screws shall be marked similarly where possible, and only on the head. Additional marking is permitted provided it does not cause confusion.
Figure 2 - Marking of bolts, screws and studs
Manufacturer’s mark. Steel grade. Property class.
Marking of hexagon head bolts and screws
Marking of hex socket head screws (marking variants)
Marking of studs
Note - Marking of left-hand threads is in accordance with ISO 898-1
3.2.2 Studs
Studs with a nominal thread diameter of 6 mm shall have marking in accordance with 3.1, Figures 1 and 2. The marking is applied on the plain part of the stud and shall include the manufacturer’s trademark, steel grade and property class. If marking on the plain part is not possible, marking of the steel grade only on the nut end of the stud is permitted (see Figure 2).
3.2.3 Packaging
All packages of any size shall be marked with the product designation and the manufacturer’s trademark.
3.3 Finishing
Unless otherwise specified, fasteners in accordance with this standard are supplied plain, without additional treatment. Passivation is recommended to achieve maximum corrosion resistance.
4 Chemical composition
The chemical composition of stainless steels for fasteners in accordance with this standard is given in Table 1.
Table 1 - Stainless steel grades. Chemical composition
| Steel class | Grade | Chemical composition, % | Footnote | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| C | Si | Mn | P | S | Cr | Mo | Ni | Cu | |||
| Austenitic | A1 | 0.12 | 1 | 6.5 | 0.2 | 0.15-0.35 | 16-19 | 0.7 | 5-10 | 1.75-2.25 | |
| A2 | 0.1 | 1 | 2 | 0.05 | 0.03 | 15-20 | - | 8-19 | 4 | ||
| A3 | 0.08 | 1 | 2 | 0.045 | 0.03 | 17-19 | - | 9-12 | 1 | ||
| A4 | 0.08 | 1 | 2 | 0.045 | 0.03 | 16-18.5 | 2-3 | 10-15 | 1 | ||
| A5 | 0.08 | 1 | 2 | 0.045 | 0.03 | 16-18.5 | 2-3 | 10.5-14 | 1 | ||
| Martensitic | C1 | 0.09-0.15 | 1 | 1 | 0.05 | 0.03 | 11.5-14 | - | 1 | - | |
| C3 | 0.17-0.25 | 1 | 1 | 0.04 | 0.03 | 16-18 | - | 1.5-2.5 | - | ||
| C4 | 0.08-0.15 | 1 | 1.5 | 0.06 | 0.15-0.35 | 12-14 | 0.6 | 1 | - | ||
| Ferritic | F1 | 0.12 | 1 | 1 | 0.04 | 0.03 | 15-18 | - | 1 | - | |
| Maximum values are given unless otherwise specified. Sulphur may be replaced by selenium. If the nickel content is less than 8%, the manganese content shall be not less than 5%. If the nickel content exceeds 8%, the lower limit for copper content does not apply. Molybdenum may be present at the steel manufacturer’s discretion. If the molybdenum content affects the conditions of use of the steel, its content shall be agreed between the steel manufacturer and the purchaser. Molybdenum may be present at the steel manufacturer’s discretion. If the chromium content is less than 17%, the nickel content shall be not less than 12%. For austenitic steels with a minimum carbon content of 0.03%, the nitrogen content shall not exceed 0.22%. For stabilization, the titanium content shall be not less than 5 × %C, but not more than 0.8%, or the niobium and/or tantalum content shall be not less than 10 × %C, but not more than 1.0%. At the steel manufacturer’s discretion, the carbon content may be higher to achieve special mechanical properties, but shall not exceed 0.12%. A titanium content of not less than 5 × %C, but not more than 0.8%, is permitted. A niobium and/or tantalum content of not less than 10 × %C, but not more than 1.0%, is permitted. | |||||||||||
| Notes 1 A description of the specified stainless steel grades, considering their properties and application areas, is given in Annex B. 2 Examples of stainless steels to ISO 683-13 and ISO 4954 are given in Annexes C and D, respectively. 3 Some materials for special applications are described in Annex E. |
The selection of chemical composition within the limits established for the steel grade is at the manufacturer’s discretion, unless the chemical composition is agreed between the manufacturer and the consumer.
If there is a risk of intergranular corrosion, testing in accordance with ISO 3651-1 or ISO 3651-2 is recommended. In such cases, it is recommended to use stabilized stainless steels A3 and A5, or stainless steels A2 and A4 with a carbon content not exceeding 0.03%.
5 Mechanical properties
The mechanical properties of bolts, screws and studs shall conform to those specified in Tables 2, 3 or 4.
Table 2 - Mechanical properties of bolts, screws and studs made of austenitic steels
| Steel class | Grade | Property class | Thread diameter range | Tensile strength, N/mm, not less than | Proof stress, N/mm, not less than | Elongation after fracture, mm, not less than |
|---|---|---|---|---|---|---|
| Austenitic | A1, A2 | 50 | M39 | 500 | 210 | 0.6 |
| A3, A4 | 70 | M24 | 700 | 450 | 0.4 | |
| A5 | 80 | M39 | 800 | 600 | 0.3 | |
| Tensile stresses are calculated based on the stress area of the bolt (see Annex A). Determined in accordance with 6.2.4 by comparing the actual length of the screw before testing with the fitted-together parts after testing, — nominal thread diameter. For fasteners with a nominal thread diameter exceeding 24 mm, the mechanical properties are agreed between the purchaser and the manufacturer, while the designations of grade and property class are in accordance with this table. |
Table 3 - Mechanical properties of bolts, screws and studs made of martensitic and ferritic steels
| Steel class | Grade | Property class | Tensile strength, N/mm, not less than | Proof stress, N/mm, not less than | Elongation after fracture, mm, not less than | Hardness | ||
|---|---|---|---|---|---|---|---|---|
| HB | HRC | HV | ||||||
| Martensitic | C1 | 50 | 500 | 250 | 0.2 | 147-209 | - | 155-220 |
| 70 | 700 | 410 | 0.2 | 209-314 | 20-34 | 220-330 | ||
| 110 | 1100 | 820 | 0.2 | - | 36-45 | 350-440 | ||
| C3 | 80 | 800 | 640 | 0.2 | 228-323 | 21-35 | 240-340 | |
| C4 | 50 | 500 | 250 | 0.2 | 147-209 | - | 155-220 | |
| 70 | 700 | 410 | 0.2 | 209-314 | 20-34 | 220-330 | ||
| Ferritic | F | 45 | 450 | 250 | 0.2 | 128-209 | - | 135-220 |
| 60 | 600 | 410 | 0.2 | 171-271 | - | 180-285 | ||
| Tensile stresses are calculated based on the stress area of the bolt (see Annex A). Determined in accordance with 6.2.4 by comparing the actual length of the screw before testing with the fitted-together parts after testing, — nominal thread diameter. Hardened and tempered at a minimum tempering temperature of 275°C. Nominal thread diameter not exceeding 24 mm. |
Table 4 - Minimum breaking torque for bolts and screws M 1.6 to M 16 (coarse pitch thread) made of austenitic steel grades
| Thread | Minimum breaking torque, N·m | ||
|---|---|---|---|
| Property class | |||
| 50 | 70 | 80 | |
| M1.6 | 0.15 | 0.2 | 0.24 |
| M2 | 0.3 | 0.4 | 0.48 |
| M2.5 | 0.6 | 0.9 | 0.96 |
| M3 | 1.1 | 1.6 | 1.8 |
| M4 | 2.7 | 3.8 | 4.3 |
| M5 | 5.5 | 7.8 | 8.8 |
| M6 | 9.3 | 13 | 15 |
| M8 | 23 | 32 | 37 |
| M10 | 46 | 65 | 74 |
| M12 | 80 | 110 | 130 |
| M16 | 210 | 290 | 330 |
For bolts and screws made of martensitic steel, the tensile strength in the wedge-loading test shall not be less than the minimum tensile strength values given in Table 3.
The mechanical property requirements specified in this section shall be met in tests carried out in accordance with the test program specified in Section 6.
The minimum breaking torque for fasteners made of martensitic and ferritic steels is agreed between the manufacturer and the purchaser.
6.1 Test program
Tests shall be carried out depending on the material grade and the length of the bolt or stud, as specified in Table 5.
Table 5 - Test program
| Grade | Tensile strength | Breaking torque | Proof stress | Elongation after fracture | Hardness | Wedge test strength |
|---|---|---|---|---|---|---|
| A1 | - | - | ||||
| A2 | - | - | ||||
| A3 | - | - | ||||
| A4 | - | - | ||||
| A5 | - | - | ||||
| C1 | - | Required | ||||
| C3 | - | Required | ||||
| C4 | - | Required | ||||
| F1 | - | Required | - | |||
| - bolt length. - nominal thread diameter. - plain shank section. | ||||||
| For all sizes not less than M5. For sizes smaller than M5, tests are carried out for all lengths. For studs, it is required that . |
6.2 Test methods
6.2.1 General requirements
The error of all dimensional measurements shall not exceed ±0.05 mm.
All tensile and elongation tests shall be carried out on testing machines fitted with self-aligning clamps to eliminate bending loads (see Figure 3). The lower holder shall be hardened and threaded for use in tests under 6.2.2-6.2.4. The hardness of the lower holder shall be not less than 45 HRC. The internal thread tolerance is 5H6G.
Figure 3 - Extensometer mounted on a bolt in self-aligning clamps
6.2.2 Tensile strength
Tensile strength is determined on fasteners with a length equal to or greater than 2.5 times the nominal thread diameter, in accordance with ISO 6892 and ISO 898-1.
The length of free thread under load shall be not less than the nominal thread diameter.
Failure shall occur between the bearing surface of the screw head and the top face of the holder.
The value obtained shall conform to the values specified in Tables 2 and 3.
6.2.3 Proof stress
The proof stress is determined on finished bolts and screws. This test is carried out only on fasteners with a length equal to or greater than 2.5 diameters.
The test is carried out by measuring the elongation of the bolt or screw under axial tensile load (see Figure 3).
The test piece shall be screwed into a hardened threaded holder to a depth of one diameter (see Figure 3).
The load-elongation diagram for the bolt is shown in Figure 4.
Figure 4 - Load-elongation diagram for determining the proof stress
The gauge length of the bolt used to calculate the proof stress is determined by the distance between the underside of the head and the threaded holder (see Figure 3 and Note 2 to Tables 2 and 3). A value equal to 0.2% of the length is marked on the horizontal axis of the load-elongation diagram, and the same value is plotted horizontally on the straight-line portion. A line drawn parallel to the elastic deformation section determines the point of intersection with the curve, which corresponds to the load at the point on the vertical axis. The load divided by the cross-sectional area of the bolt gives the proof stress.
Elongation occurs between the bearing surface of the bolt head and the end of the holder.
6.2.4 Elongation at fracture
Elongation at fracture is determined on fasteners with a length equal to or greater than 2.5 diameters.
The length of the screw shall be measured before testing (see Figure 5). The test piece is then screwed into the threaded holder to a depth of one diameter (see Figure 3).
Figure 5 - Determination of elongation at fracture A
After the part has fractured, its pieces shall be fitted back together for re-measuring the length (see Figure 5).
The elongation value obtained shall be greater than the values specified in Tables 2 and 3.
When testing machined test specimens, elongation values shall be agreed separately.
6.2.5 Breaking torque
The breaking torque is determined using the special device shown in Figure 6. The torque testing device shall have an accuracy of at least 7% of the minimum value specified in Table 4.
Figure 6 - Device for determining breaking torque
1 - split clamp; 2 - blind hole
The screw thread shall be clamped to a length of one diameter in a split die with a blind hole so that at least two full threads are above the clamping device.
Torque shall be applied to the screw until failure occurs. The screw shall withstand, without failure, the minimum torque specified in Table 4.
6.2.6 Wedge-loading tensile test for bolts and screws made of martensitic steels
The test is carried out in accordance with ISO 898-1; the washer dimensions are given in Table 6.
Table 6 - Wedge washer dimensions
| Nominal thread diameter of bolt or screw , mm | ||
|---|---|---|
| Bolts and screws with a plain shank length | Bolts and screws threaded up to the head or with a plain shank length | |
| 20 | 10°±30’ | 6°±30’ |
| 2039 | 6°±30’ | 4°±30’ |
6.2.7 Hardness test (HB, HRC or HV)
The hardness test is carried out in accordance with ISO 6506 (HB), ISO 6508 (HRC) or ISO 6507-1 (HV). In disputed cases, the decisive criterion for acceptance is the Vickers hardness test (HV). The hardness test shall be carried out on the end of the bolt, at half the radius between the centre and the thread surface. In disputed cases, this zone is selected at a distance of one diameter from the end of the bolt.
Hardness values shall be within the limits specified in Table 3.
Annex A (mandatory). External thread. Determination of the stress area of the bolt
The stress area is calculated using a formula that uses the nominal pitch diameter of the thread and the minor diameter of the thread, calculated from the nominal basic minor diameter of the thread and the height of the fundamental triangle of the thread (see ISO 724).
Table A.1 - Nominal stress area for coarse and fine pitch threads
| With coarse thread pitch | Nominal stress area , mm | With fine thread pitch | Nominal stress area , mm |
|---|---|---|---|
| M1.6 | 1.27 | M8×1 | 39.2 |
| M2 | 2.07 | M10×1 | 64.5 |
| M2.5 | 3.39 | M10×1.25 | 61.2 |
| M3 | 5.03 | M12×1.25 | 92.1 |
| M4 | 8.78 | M12×1.5 | 88.1 |
| M5 | 14.2 | M14×1.5 | 125 |
| M6 | 20.1 | M16×1.5 | 167 |
| M8 | 36.6 | M18×1.5 | 216 |
| M10 | 58 | M20×1.5 | 272 |
| M12 | 84.3 | M22×1.5 | 333 |
| M14 | 115 | M24×2 | 384 |
| M16 | 157 | M27×2 | 496 |
| M18 | 192 | M30×2 | 621 |
| M20 | 245 | M33×2 | 761 |
| M22 | 303 | M36×3 | 865 |
| M24 | 353 | M39×3 | 1030 |
| M27 | 459 | ||
| M30 | 561 | ||
| M33 | 694 | ||
| M36 | 817 | ||
| M39 | 976 | ||
| - fine thread pitch. |
Annex B (informative). Description of classes and grades of stainless steels
C.1 General description
ISO 3506-2, ISO 3506-3 and this standard describe steel grades A1 to A5, C1 to C4 and F1, which belong to the following steel classes:
| austenitic steel | A1 to A5; |
|---|---|
| martensitic steel | C1 to C4; |
| ferritic steel | F1. |
This annex describes the characteristics of the listed steel classes and grades.
This annex also provides information on the non-standardized FA steel class, which has a ferritic-austenitic structure.
C.2 Class A steels (austenitic structure)
ISO 3506-2, ISO 3506-3 and this standard describe five basic grades of austenitic steels - A1 to A5. Steels of these grades cannot be hardened and are generally non-magnetic. To improve wear resistance, copper may be added to grades A1 to A5, as specified in Table 1.
The following applies to unstabilized steels of grades A2 and A4.
Since chromium oxide increases the corrosion resistance of steel, a low carbon content is of great importance for unstabilized steels. Because of the high affinity between chromium and carbon, chromium carbide forms instead of chromium oxide, especially at elevated temperatures (see Annex G).
The following applies to stabilized steels of grades A3 and A5.
The elements Ti, Nb or Ta act on the carbon, allowing chromium oxide to fully exhibit its properties.
For use offshore or in similar conditions, steels containing approximately 20% chromium and nickel and 4.5% to 6.5% molybdenum are required.
In cases of high probability of corrosion, consultation with experts shall be carried out.
C.2.1 Grade A1 steels
Grade A1 steels are designed for use in mechanical engineering. Due to their high sulfur content, steels of this grade are less corrosion-resistant than other grades in this group.
C.2.2 Grade A2 steels
Grade A2 steels are the most commonly used stainless steels. They are used for kitchen equipment and chemical process equipment. Steels of this grade are not suitable for use with non-oxidizing acids and chlorine-containing compounds, such as in seawater and swimming pools.
C.2.3 Grade A3 steels
Grade A3 steels are stabilized stainless steels with the properties of grade A2 steels.
C.2.4 Grade A4 steels
Grade A4 steels are acid-resistant, alloyed with molybdenum, and more corrosion-resistant. Grade A4 steels are most in demand in the paper industry, since this grade is designed for use with sulfuric acid, and are also to some extent suitable for use in chlorine-containing environments. Grade A4 steels are also often used in the food and shipbuilding industries.
C.2.5 Grade A5 steels
Grade A5 steels are stabilized acid-resistant steels with the properties of grade A4 steels.
C.3 Class F steels (ferritic structure)
ISO 3506-2, ISO 3506-3 and this standard describe one grade of ferritic steels, F1. Steels of this class are generally not permitted to be hardened, and should not be hardened in cases where it is possible. Grade F1 steels are magnetic.
C.3.1 Grade F1 steels
Grade F1 steels are typically used for uncomplicated equipment, with the exception of super-ferritic steels, which have a very low carbon and nitrogen content. Such steels can replace grades A2 and A3 and can be used in environments with a high chlorine content.
B.4 Class C steels (martensitic structure)
ISO 3506-2, ISO 3506-3 and this standard describe martensitic steel grades C1, C3 and C4. Steels of this class can be hardened to very high strength. Steels of this class are magnetic.
B.4.1 Grade C1 steels
Grade C1 steels have limited corrosion resistance. They are used in turbines, pumps, and for knives.
B.4.2 Grade C3 steels
Grade C3 steels have limited corrosion resistance, although better than grade C1 steels. They are used in pumps and valves.
B.4.3 Grade C4 steels
Grade C4 steels have limited corrosion resistance. They are used in mechanical engineering, and are otherwise similar to grade C1 steels.
B.5 Class FA steels (ferritic-austenitic structure)
Class FA steels are not described in ISO 3605-2, ISO 3605-3 or this standard, but are quite likely to be described in the future.
Steels of this class are called duplex steels. The first class FA steels had certain shortcomings, which have been eliminated in more recently developed steels. Class FA steels are better than grades A4 and A5, especially in terms of strength characteristics. Class FA steels also have increased resistance to pitting and crevice corrosion.
Examples of the chemical composition of steels of this class are given in Table B.1.
Table B.1 - Chemical composition of ferritic-austenitic steels
| Steel class | Chemical composition, % | ||||||
|---|---|---|---|---|---|---|---|
| C, max | Si | Mn | Cr | Ni | Mo | N | |
| Ferritic-austenitic | 0.03 | 1.7 | 1.5 | 18.5 | 5 | 2.7 | 0.07 |
| 0.03 | 1 | 2 | 22 | 5.5 | 3 | 0.14 |
Annex C (informative). Chemical composition of stainless steels
(extracts from ISO 683-13:1986)
Table C.1
| Steel type | Chemical composition, % | Fastener grade designation | |||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| C | Si | Mn | P | S | N | Al | Cr | Mo | Nb | Ni | Se, min | Ti | Cu | ||||
| max | |||||||||||||||||
| Ferritic steels | |||||||||||||||||
| 8 | 0.08 max | 1.0 | 1.0 | 0.040 | 0.030 max | - | - | 16.0-18.0 | - | - | 1.0 max | - | - | - | F1 | ||
| 8b | 0.07 max | 1.0 | 1.0 | 0.040 | 0.030 max | - | - | 16.0-18.0 | - | - | 1.0 max | - | 7 x % C1.1 | - | F1 | ||
| 9c | 0.08 max | 1.0 | 1.0 | 0.040 | 0.030 max | - | - | 16.0-18.0 | 0.90-1.30 | - | 1.0 max | - | - | - | F1 | ||
| F1 | 0.025 max | 1.0 | 1.0 | 0.040 | 0.030 max | 0.025 max | - | 17.0-19.0 | 1.75-2.50 | - | 0.60 max | - | - | - | F1 | ||
| Martensitic steels | |||||||||||||||||
| 3 | 0.09-0.15 | 1.0 | 1.0 | 0.040 | 0.030 max | - | - | 11.5-13.5 | - | - | 1.0 max | - | - | - | C1 | ||
| 7 | 0.08-0.15 | 1.0 | 1.5 | 0.060 | 0.15-0.35 | - | - | 12.0-14.0 | 0.60 max | - | 1.0 max | - | - | - | C4 | ||
| 4 | 0.16-0.25 | 1.0 | 1.0 | 0.040 | 0.030 max | - | - | 12.0-14.0 | - | - | 1.0 max | - | - | - | C1 | ||
| 9a | 0.10-0.17 | 1.0 | 1.5 | 0.060 | 0.15-0.34 | - | - | 15.5-17.5 | 0.60 max | - | 1.0 max | - | - | - | C3 | ||
| 9b | 0.14-0.23 | 1.0 | 1.0 | 0.040 | 0.030 max | - | - | 15.0-17.5 | - | - | 1.5-2.5 | - | - | - | C3 | ||
| 5 | 0.26-0.35 | 1.0 | 1.0 | 0.040 | 0.030 max | - | - | 12.0-14.0 | - | - | 1.0 max | - | - | - | C1 | ||
| Austenitic steels | |||||||||||||||||
| 10 | 0.030 max | 1.0 | 2.0 | 0.045 | 0.030 max | - | - | 17.0-19.0 | - | - | 9.0-12.0 | - | - | - | A2 | ||
| 11 | 0.07 max | 1.0 | 2.0 | 0.045 | 0.030 max | - | - | 17.0-19.0 | - | - | 8.0-11.0 | - | - | - | A2 | ||
| 15 | 0.08 max | 1.0 | 2.0 | 0.045 | 0.030 max | - | - | 17.0-19.0 | - | - | 9.0-12.0 | - | 5 x % C0.8 | - | A3 | ||
| 16 | 0.08 max | 1.0 | 2.0 | 0.045 | 0.030 max | - | - | 17.0-19.0 | - | 10x%C1.0 | 9.0-12.0 | - | - | - | A3 | ||
| 17 | 0.12 max | 1.0 | 2.0 | 0.060 | 0.15-0.35 | - | - | 17.0-19.0 | - | - | 8.0-10.0 | - | - | - | A1 | ||
| 13 | 0.10 max | 1.0 | 2.0 | 0.045 | 0.030 max | - | - | 17.0-19.0 | - | - | 11.0-13.0 | - | - | - | A2 | ||
| 19 | 0.030 max | 1.0 | 2.0 | 0.045 | 0.030 max | - | - | 16.5-18.5 | 2.0-2.5 | - | 11.0-14.0 | - | - | - | A4 | ||
| 20 | 0.07 max | 1.0 | 2.0 | 0.045 | 0.030 max | - | - | 16.5-18.5 | 2.0-2.5 | - | 10.5-13.5 | - | - | - | A4 | ||
| 21 | 0.08 max | 1.0 | 2.0 | 0.045 | 0.030 max | - | - | 16.5-18.5 | 2.0-2.5 | - | 11.0-14.0 | - | 5 x % C0.8 | - | A5 | ||
| 23 | 0.08 max | 1.0 | 2.0 | 0.045 | 0.030 max | - | - | 16.5-18.5 | 2.0-2.5 | 10x%C1.0 | 11.0-14.0 | - | - | - | A5 | ||
| 19a | 0.030 max | 1.0 | 2.0 | 0.045 | 0.030 max | - | - | 16.5-18.5 | 2.5-3.0 | - | 11.5-14.5 | - | - | - | A4 | ||
| 20a | 0.07 max | 1.0 | 2.0 | 0.045 | 0.030 max | - | - | 16.5-18.5 | 2.5-3.0 | - | 11.0-14.0 | - | - | - | A4 | ||
| 10N | 0.030 max | 1.0 | 2.0 | 0.045 | 0.030 max | 0.12-0.22 | - | 17.0-19.0 | - | - | 8.5-11.5 | - | - | - | A2 | ||
| 19N | 0.030 max | 1.0 | 2.0 | 0.045 | 0.030 max | 0.12-0.22 | - | 16.5-18.5 | 2.0-2.5 | - | 10.5-13.5 | - | - | - | A4 | ||
| 19aN | 0.030 max | 1.0 | 2.0 | 0.045 | 0.030 max | 0.12-0.22 | - | 16.5-18.5 | 2.5-3.0 | - | 11.5-14.5 | - | - | - | A4 | ||
| Elements not listed in this table shall not be added to the steel without agreement between the steel manufacturer and purchaser, except for elements intended to complete the melt. All necessary precautions shall be taken to prevent elements from scrap and materials used in production, which could affect the strength, mechanical properties and applicability of the steel, from entering the steel. Type numbers are provisional and will be revised when the relevant standard is issued. Tantalum is designated as niobium. Not in accordance with ISO 683-13. (C+N) not more than 0.040%. 8×(C+N)(Nb+Ti)0.80%. By agreement, when placing an order, the steel may be supplied with a Mo content of 0.20%–0.60%. High resistance to intergranular corrosion. Stabilized steels. The manufacturer may add molybdenum up to 0.70%. |
Annex D (informative). Stainless steels for cold heading and forming
(extracts from ISO 4954:1993)
Table D.1
| Steel type (designation) | Chemical composition, % | Fastener grade designation | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Number | Designation | According to ISO 4954 | C | Si | Mn | P | S | Cr | Mo | Ni | Other | |
| max | ||||||||||||
| Ferritic steels | ||||||||||||
| 71 | X 3 Cr 17 E | - | 0.04 | 1.00 | 1.00 | 0.040 | 0.030 | 16.0-18.0 | 1.0 | F1 | ||
| 72 | X 6 Cr 17 E | D1 | 0.08 | 1.00 | 1.00 | 0.040 | 0.030 | 16.0-18.0 | 1.0 | F1 | ||
| 73 | X 6 CrMo 17 1 E | D2 | 0.08 | 1.00 | 1.00 | 0.040 | 0.030 | 16.0-18.0 | 0.90-1.30 | 1.0 | F1 | |
| 74 | X 6 CrTi 12 E | - | 0.08 | 1.00 | 1.00 | 0.040 | 0.030 | 10.5-12.5 | 0.50 | Ti: 6 x % C1.0 | F1 | |
| 75 | X 6 CrNb 12 E | - | 0.08 | 1.00 | 1.00 | 0.040 | 0.030 | 10.5-12.5 | 0.50 | Nb: 6 x % C1.0 | F1 | |
| Martensitic steels | ||||||||||||
| 76 | X 12 Cr 13 E | D 10 | 0.90-0.15 | 1.00 | 1.00 | 0.040 | 0.030 | 11.5-13.5 | 1.0 | C1 | ||
| 77 | X 19 CrNi 16 2 E | D 12 | 0.14-0.23 | 1.00 | 1.00 | 0.040 | 0.030 | 15.0-17.5 | 1.5-2.5 | C3 | ||
| Austenitic steels | ||||||||||||
| 78 | X 2 CrNi 18 10 E | D 20 | 0.030 | 1.00 | 2.00 | 0.045 | 0.030 | 17.0-19.0 | 9.0-12.0 | A2 | ||
| 79 | X 5 CrNi 18 9 E | D 21 | 0.07 | 1.00 | 2.00 | 0.045 | 0.030 | 17.0-19.0 | 8.0-11.0 | A2 | ||
| 80 | X 10 CrNi 18 9 E | D 22 | 0.12 | 1.00 | 2.00 | 0.045 | 0.030 | 17.0-19.0 | 8.0-10.0 | A2 | ||
| 81 | X 5 CrNi 18 12 E | D 23 | 0.07 | 1.00 | 2.00 | 0.045 | 0.030 | 17.0-19.0 | 11.0-13.0 | A2 | ||
| 82 | X 6 CrNi 18 16 E | D 25 | 0.08 | 1.00 | 2.00 | 0.045 | 0.030 | 15.0-17.0 | 17.0-19.0 | A2 | ||
| 83 | X 6 CrNiTi 18 10 E | D 26 | 0.08 | 1.00 | 2.00 | 0.045 | 0.030 | 17.0-19.0 | 9.0-12.0 | Ti: 5 x % C0.80 | A3 | |
| 84 | X 5 CrNiMo 17 12 2 E | D 29 | 0.07 | 1.00 | 2.00 | 0.045 | 0.030 | 16.5-18.5 | 2.0-2.5 | 10.5-13.5 | A4 | |
| 85 | X 6 CrNiMoTi 17 12 2 E | D 30 | 0.08 | 1.00 | 2.00 | 0.045 | 0.30 | 16.5-18.5 | 2.0-2.5 | 11.0-14.0 | Ti: 5 x % C0.80 | A5 |
| 86 | X 2 CrNiMo 17 13 3 E | - | 0.030 | 1.00 | 2.00 | 0.045 | 0.030 | 16.5-18.5 | 2.5-3.0 | 11.5-14.5 | A4 | |
| 87 | X 2 CrNiMoN 17 13 3 E | - | 0.030 | 1.00 | 2.00 | 0.045 | 0.030 | 16.5-18.5 | 2.5-3.0 | 11.5-14.5 | N: 0.12-0.22 | A4 |
| 88 | X 3 CrNiCu 18 9 3 E | D 32 | 0.04 | 1.00 | 2.00 | 0.045 | 0.030 | 17.0-19.0 | 8.5-10.5 | Cu: 3.00-4.00 | A2 | |
| The first column gives sequential numbers. The second column gives designations in accordance with the system proposed by ISO Technical Committee ISO/TC 17/SC 2. The third column gives former numbers according to ISO 4954 (revised 1993). Elements not listed in this table shall not be added to the steel without agreement between the steel manufacturer and purchaser, except for elements intended to complete the melt. All necessary precautions shall be taken to prevent elements from scrap and materials used in production, which could affect the strength, mechanical properties and applicability of the steel, from entering the steel. Not in accordance with ISO 4954. Very high resistance to intergranular corrosion. |
Annex E (informative). Austenitic stainless steels with special resistance to chlorides causing stress corrosion
(extracts from EN 10088-1:1995)
The risk of failure of bolts, screws and studs due to chloride corrosion (for example, inside swimming pools) can be reduced by using the materials specified in Table E.1.
Table E.1
| Austenitic stainless steels (designation/material number) | Chemical composition, % | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| C | Si | Mn | P | S | N | Cr | Mo | Ni | Cu | |
| max | ||||||||||
| X2CrNiMoN17-13-5 (1.4439) | 0.03 | 1.0 | 2.0 | 0.045 | 0.015 | 0.12-0.22 | 16.5-18.5 | 4.0-5.0 | 12.5-14.5 | |
| X1NiCrMoCu25-20-5 (1.4539) | 0.02 | 0.7 | 2.0 | 0.030 | 0.010 | 0.15 | 19.0-21.0 | 4.0-5.0 | 24.0-26.0 | 1.2-2.0 |
| X1NiCrMoCuN25-20-7 (1.4529) | 0.02 | 0.5 | 1.0 | 0.030 | 0.010 | 0.15-0.25 | 19.0-21.0 | 6.0-7.0 | 24.0-26.0 | 0.5-1.5 |
| X2CrNiMoN22-5-3 (1.4462) | 0.03 | 1.0 | 2.0 | 0.035 | 0.015 | 0.10-0.22 | 21.0-23.0 | 2.5-3.5 | 4.5-6.5 | |
| Austenitic-ferritic steels. |
Annex F (informative). Mechanical properties at elevated temperatures, use at low temperatures
Note - If bolts, screws and studs are correctly dimensioned, the mating nuts will automatically match them. Therefore, when used at elevated or low temperatures, it is sufficient to take into account only the mechanical properties of the bolts, screws and studs.
F.1 Reduction in yield strength or proof stress at elevated temperatures
The values given in this annex are for reference only. Users should understand that the actual chemical environment, loading of installed fasteners, and ambient conditions may differ significantly. If loads are not constant and the period of exposure to elevated temperature is significant, or there is a high likelihood of stress corrosion, the user should consult the manufacturer.
Values of yield strength or proof stress at elevated temperatures, expressed as a percentage of the values at room temperature, are given in Table F.1.
Table F.1 - Effect of temperature on yield strength
| Steel grade | and , %, at temperature | |||
|---|---|---|---|---|
| 100 °C | 200 °C | 300 °C | 400 °C | |
| A2A4 | 85 | 80 | 75 | 70 |
| C1 | 95 | 90 | 80 | 65 |
| C3 | 90 | 85 | 80 | 60 |
| Note — The values apply only to property classes 70 and 80. |
F.2 Use at low temperatures
See Table F.2 for the use of stainless steel bolts, screws and studs at low temperatures.
Table F.2 - Use of stainless steel bolts, screws and studs at low temperatures (austenitic steels only)
| Steel grade | Lower limit of operating temperature for sustained exposure | |
|---|---|---|
| A2 | -200 °C | |
| A4 | Bolts and screws | -60 °C |
| Studs | -200 °C | |
| Due to the presence of the alloying element Mo, the stability of austenite decreases and the transition temperature shifts to higher values if the fasteners were subjected to a high degree of deformation during manufacturing. |
Annex G (informative). Time-temperature diagram of intergranular corrosion in grade A2 austenitic stainless steel
Figure G.1 shows the approximate time to onset of intergranular corrosion risk for grade A2 austenitic stainless steel (18/8 steel) with various carbon contents at temperatures from 550 °C to 925 °C.
Figure G.1
Annex H (informative). Magnetic properties of austenitic stainless steels
All fasteners made of austenitic stainless steels are non-magnetic under normal conditions, but may exhibit magnetic properties after cold forming.
Every material is characterized by its ability to become magnetized, and this also applies to stainless steels. Only a vacuum can be completely non-magnetic. The magnetic permeability of a material is expressed as a coefficient showing the ratio of the material’s magnetic permeability to that of a vacuum. A material has low magnetic permeability if its coefficient is close to 1.
Examples:
| A2: | 1.8; |
|---|---|
| A4: | 1.015; |
| A4L: | 1.005; |
| F1: | 5. |
Annex DA (informative). Information on the correspondence of the referenced international standards to the referenced national standards of the Russian Federation and the interstate standards currently in effect in that capacity
| Designation of the referenced international standard | Degree of conformity | Designation and title of the corresponding national standard |
|---|---|---|
| ISO 68-1 | MOD | GOST 9150-2002 (ISO 68-1:1998) “Basic norms of interchangeability. Metric thread. Profile” |
| ISO 261 | MOD | GOST 8724-2002 (ISO 261:1998) “Basic norms of interchangeability. Metric thread. Diameters and pitches” |
| ISO 262** | - | * |
| _______________ ** Access to the international and foreign documents referenced in the text, here and throughout, can be obtained by following the link. - Database compiler’s note. | ||
| ISO 724:1993 | MOD | GOST 24705-2004 (ISO 724:1993) “Basic norms of interchangeability. Metric thread. Basic dimensions” |
| ISO 898-1:1999 | MOD | GOST R 52627-2006 (ISO 898-1:1999) “Bolts, screws and studs. Mechanical properties and test methods” |
| ISO 3651-1** | - | * |
| ISO 3651-2** | - | * |
| ISO 6506:1981 | NEQ | GOST 9012-59 “Metals. Method of Brinell hardness measurement” |
| ISO 6507-1:1997 | IDT | GOST R ISO 6507-1-2007 “Metals and alloys. Vickers hardness test. Part 1. Test method” |
| ISO 6508:1986 | NEQ | GOST 9013-59 “Metals. Method of Rockwell hardness measurement” |
| ISO 6892** | - | * |
| ISO 8044** | - | * |
| * No corresponding national standard exists. Until it is adopted, it is recommended to use the Russian translation of this international standard. The translation of this international standard is held in the Federal Information Fund of Technical Regulations and Standards. Note - This table uses the following designations for the degree of conformity of standards: - IDT - identical standards; - MOD - modified standards; - NEQ - non-equivalent standards. |
Bibliography
| [1] | ISO 683-13:1986**, Heat-treated steels, alloy steels and free cutting steels - Part 13: Wrought stainless steels. |
|---|---|
| [2] | ISO 4954:1993**, Steels for cold heading and cold extruding. |
| [3] | EN 10088-1:1995**, Stainless steels - Part 1: List of stainless steels |
Estimate for the “GOST R ISO 3506-1” category
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