GOST ISO 3506-1-2014 Mechanical Properties of Corrosion-Resistant Stainless Steel Fasteners. Part 1. Bolts, Screws and Studs

GOST ISO 3506-1-2014 establishes the mechanical properties of bolts, screws and studs made of austenitic, martensitic and ferritic corrosion-resistant stainless steels, when tested in the temperature range from 15°C to 25°C. If the temperature deviates from this range, the mechanical properties change.

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.

The standard does not apply to products with special properties, such as weldability, and does not establish requirements for corrosion resistance or oxidation resistance under special environmental conditions — some information on this is given in Annex E. Definitions of corrosion and corrosion resistance are adopted from ISO 8044.

The standard classifies corrosion-resistant stainless steel fasteners by property class. Some grades are used at low temperatures down to minus 200°C, others at high temperatures up to 800°C; the effect of temperature on mechanical properties is described in Annex F. Corrosion resistance, oxidation resistance and mechanical properties at elevated and reduced temperatures are agreed between the manufacturer and the purchaser on a case-by-case basis. The dependence of the risk of intercrystalline corrosion on carbon content at elevated temperature is shown in Annex G.

Fasteners made of austenitic steels are non-magnetic under normal conditions; magnetic properties may appear after cold forming (Annex H).

2 Normative references

References are given to ISO 68-1, ISO 261, ISO 262, ISO 724:1993, ISO 898-1:1999, ISO 3651-1, ISO 3651-2, ISO 6506:1981, ISO 6507-1:1997, ISO 6508:1986, ISO 6892, ISO 8044.

3.1 Designations

The designation of the steel grade and property class consists of two parts separated by a hyphen: steel grade and property class (Figure 1). Steel classes are described in Annex B and defined by chemical composition in accordance with Table 2. Steels with a carbon content not exceeding 0.03% are additionally marked with the letter L (example — A4L-80).

The first part of the designation is the steel class letter:

• A — austenitic steel;
• C — martensitic steel;
• F — ferritic steel,

and a digit indicating the chemical composition range of the class. The second part is two digits indicating 0.1 of the minimum tensile strength.

Examples: austenitic cold-worked steel with a tensile strength of at least 700 N/mm² (700 MPa) — A2-70; martensitic hardened and tempered steel with the same tensile strength — C4-70.

3.2 Marking

3.2.1 Bolts and screws. Hexagon head bolts and screws and hex socket screws with a thread diameter of 5 mm or more shall be marked in accordance with 3.1 with the steel grade, property class and the manufacturer’s trademark. Other types are marked in the same way, where possible, on the head only. Additional marking is permitted provided it does not cause confusion.

3.2.2 Studs. Studs with a thread diameter of 6 mm or more are marked on the plain part: manufacturer’s trademark, steel grade, property class. If this is not possible, the steel grade may be marked on the nut end only.

3.2.3 Packaging. Packaging of any size shall bear the product designation and the manufacturer’s trademark.

3.3 Finishing

Unless otherwise specified, fasteners are supplied plain without additional treatment. Passivation is recommended for maximum corrosion resistance.

4 Chemical composition

The chemical composition of stainless steels for fasteners is given in Table 1.

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 choice of chemical composition within the established limits of the grade is at the manufacturer’s discretion unless agreed otherwise with the purchaser. Where there is a risk of intercrystalline corrosion, testing to ISO 3651-1 or ISO 3651-2 is recommended; in such cases, stabilized grades A3 and A5, or grades A2 and A4 with a carbon content not exceeding 0.03%, are used.

5 Mechanical properties

The mechanical properties of bolts, screws and studs shall conform to Tables 2, 3 or 4.

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.

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.

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 determined in the wedge test shall not be less than the minimum values given in Table 3. Testing is carried out according to the program specified in Section 6. The minimum breaking torque for martensitic and ferritic steels is agreed between the manufacturer and the purchaser.

6.1 Test program

Tests are carried out depending on the material grade and the length of the bolt or stud in accordance with Table 5.

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 measurement error for dimensions shall not exceed ±0.05 mm. Tensile and fracture tests are carried out on machines with self-aligning grips to eliminate bending loads (Figure 3). The lower holder is hardened, threaded, with a hardness of not less than 45 HRC, and an internal thread tolerance of 5H6G.

6.2.2 Tensile strength. Determined on products with a length of 2.5 thread diameters or more, 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. Fracture occurs between the bearing surface of the head and the top plane of the holder. The resulting values are compared with Tables 2 and 3.

6.2.3 Proof stress. Determined on finished bolts and screws with a length of 2.5 diameters or more by measuring elongation under an axial tensile load (Figure 3). The part is screwed into a hardened holder to a depth of one diameter. The elongation-versus-load diagram is shown in Figure 4. A value of 0.2% of length is plotted on the diagram to determine the yield point.

6.2.4 Elongation after fracture. Determined on products with a length of 2.5 diameters or more (Figures 3 and 5). After fracture, the parts of the product are fitted back together and the length is measured again; the resulting elongation is compared with the values in Tables 2 and 3.

6.2.5 Breaking torque. Determined using the device shown in Figure 6 with an accuracy of at least 7% of the minimum value given in Table 4. The thread is clamped over a length of one diameter so that at least two thread turns remain above the clamp. The screw shall withstand, without failure, the minimum torque given in Table 4.

6.2.6 Wedge tensile test for martensitic steels. Carried out in accordance with ISO 898-1; washer dimensions are given in Table 6.

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). Carried out in accordance with ISO 6506 (HB), ISO 6508 (HRC) or ISO 6507-1 (HV). In case of dispute, the Vickers test is decisive. The test zone is selected at the end of the bolt, at half the radius between the center and the thread surface, or at a distance of one diameter from the end. Hardness values shall comply with Table 3.

Annex A (mandatory). Determination of the stress area of a bolt

The stress area is calculated using a formula based on the nominal pitch diameter of the thread and the minor diameter of the thread.

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

B.1 ISO 3506-2, ISO 3506-3 and this standard describe grades A1–A5, C1–C4 and F1.

austenitic steel	A1 to A5;
martensitic steel	C1 to C4;
ferritic steel	F1.

Information is also given on the non-standardized class FA with a ferritic-austenitic structure.

B.2 Grade A steels (austenitic structure). The five grades A1–A5 are not hardenable and are generally non-magnetic; copper may be added to improve wear resistance (Table 1). For the non-stabilized grades A2 and A4, a low carbon content is important, since chromium carbide forms instead of chromium oxide at elevated temperatures (Annex G). In the stabilized grades A3 and A5, the elements Ti, Nb or Ta bind the carbon, allowing the chromium oxide to fully exhibit its protective properties. For marine and similar environments, steels with a chromium and nickel content of about 20% and a molybdenum content of 4.5–6.5% are used. Where there is a high likelihood of corrosion, specialist consultation is required.

• A1 — for mechanical engineering; due to its high sulfur content, it is less corrosion-resistant.
• A2 — the most widely used grade; for kitchen equipment and chemical apparatus; not suitable for use with non-oxidizing acids and chlorides.
• A3 — a stabilized counterpart of A2.
• A4 — acid-resistant, alloyed with molybdenum; for the paper, food and shipbuilding industries, suitable for sulfuric acid and partially chloride environments.
• A5 — a stabilized counterpart of A4.

B.3 Grade F steels (ferritic structure). Grade F1 is generally not hardenable and is magnetic; used for simple equipment. Super-ferritic steels with low carbon and nitrogen content can replace A2 and A3 in environments with high chlorine content.

B.4 Grade C steels (martensitic structure). Grades C1, C3 and C4 can be hardened to high strength and are magnetic.

• C1 — limited corrosion resistance; turbines, pumps, knives.
• C3 — limited resistance, but better than C1; pumps and valves.
• C4 — limited resistance; mechanical engineering, similar to C1.

B.5 Grade FA steels (ferritic-austenitic structure, duplex). Not described in ISO 3506-2, ISO 3506-3 or this standard. They exceed grades A4 and A5 in strength and have increased resistance to pitting and crevice corrosion.

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)

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)

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 steels with special resistance to chloride corrosion

(extracts from EN 10088-1:1995)

To reduce the risk of fastener failure due to chloride corrosion, the materials given in Table E.1 are used.

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

If bolts, screws and studs are correctly designed, the mating nuts correspond to them automatically, so for elevated or low temperatures it is sufficient to consider the properties of the fastener.

F.1 The values are for reference; in the case of variable loads, prolonged exposure to elevated temperatures, or risk of stress corrosion, the purchaser should consult the manufacturer.

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 — 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). Temperature-time diagram of intergranular corrosion in A2 steel

Approximate time for the risk of intergranular corrosion to appear for A2 (18/8) steel with varying carbon content at temperatures from 550 °C to 925 °C.

Annex H (informative). Magnetic properties of austenitic stainless steels

Fasteners made of austenitic steels are non-magnetic under normal conditions, but may exhibit magnetic properties after cold deformation. The magnetic permeability of the material is denoted by a coefficient showing the ratio to the permeability of a vacuum; a value close to 1 indicates low magnetic permeability.

A2:	1.8;
A4:	1.015;
A4L:	1.005;
F1:	5.

Annex DA (informative). Correspondence between referenced international and national standards

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