ISO 3506-1 Fasteners, Boltings, Stud Bolts, Screws

ISO 3506-1 Scope

ISO 3506-1 Specification concludes the mechanical and physical properties of bolts, screws and stud bolts, with coarse pitch thread and fine pitch thread, made of corrosion-resistant stainless steels, when tested at the ambient temperature range of 10 °C to 35 °C. It specifies property classes in relation to austenitic, martensitic, ferritic and duplex (austenitic-ferritic) steel grades for fasteners.
ISO 3506-1 Fasteners conforming to the requirements of this specification are used without restriction in applications ranging from -20 °C to +150 °C; however, fasteners conforming to this document are also used for applications outside this range down to -196 °C and up to +300 °C. ISO 3506-1 specification is applicable for Stud Bolts, Screws, Bolts with coarse pitch thread M1,6 to M39, and fine pitch thread M8×1 to M39×3 and diameter/pitch combinations in accordance with ISO 261 and ISO 262.

Designation of ISO 3506-1 Stainless Steel Fasteners

Common Designations for cold heading

Type Of Steel/Alloy	Grade	Steel Number	Steel Designation	UNS	Trade Name
Resulfurized austenitic	A1	1.4305	X8CrNiS18-9	S30300	303
	A1	1.4570	X6CrNiCuS18-9-2	-	303Cu
General purpose austenitic	A2L	1.4307	X2CrNi18-9	S30403	304L
	A2L	1.4306	X2CrNi19-11	S30403	304L
	A2L	1.4311	X2CrNiN18-9	S30453	304LN
	A2	1.4301	X5CrNi18-10	S30400	304
	A2	1.4567	X3CrNiCu18-9-4	S30430	304Cu
	A2	1.4560	X3CrNiCu19-9-2	-	304Cu
	A2	1.4303	X4CrNi18-12	S30500	305
	A3	1.455	X6CrNiNb18-10	S34700	347
	A3	1.4541	X6CrNiTi18-10	S32100	321
	-	1.4615	X3CrMnNiCu15-8-5-3	-	201Cu
	-	1.4310	X10CrNi18-8	S30100	301
Molybdenum containing austenitic	A4	1.4401	X5CrNiMo17-12-2	S31600	316
	A4L	1.4404	X2CrNiMo17-12-2	S31603	316L
	A4L	1.4406	X2CrNiMoN17-11-2	S31653	316LN
	A4L	1.4432	X2CrNiMo17-12-3	S31603	316L
	A4L	1.4435	X2CrNiMo18-14-3	S31603	316L
	A4	1.4436	X3CrNiMo17-13-3	S31600	316
	A4	1.4578	X3CrNiCuMo17-11-3-2	-	-
	A5	1.4571	X6CrNiMoTi17-12-2	S31635	316Ti
High molybdenum super-austenitic	A8	1.4478	X2NiCrMoN25-21-7	N08367	AL-6XN
	A8	1.4529	X1NiCrMoCuN25-20-7	N08926	926
	A8	1.4547	X1CrNiMoCuN20-18-7	S31254	F44
Highly alloyed austenitic for special purposes	S	1.4986	X7CrNiMoBNb16-16	-	-
	-	1.4539	X1NiCrMoCu25-20-5	N08904	904L
	-	1.4841	X15CrNiSi25-21	S31400	314
	-	1.4828	X15CrNiSi20-12	-	309
	-	1.4845	X8CrNi25-21	S31008	310S
High manganese super-austenitic	-	1.4020	X13CrMnNiN18-13-2	S24100	XM28
	-	1.4378	X6CrMnNiN18-13-3	S24000	XM29
General purpose martensitic	C1	1.4006	X12Cr13	S41000	410
	C1	1.4000	X6Cr13	S41008	410S
	C1, CH0	1.4021	X20Cr13	S42000	420
	C1, CH1	1.4028	X30Cr13	S42000	420
	C1	1.4034	X46Cr13	S42000	420
	-	1.4003	X2CrNi12	S41003	410L
High Chromium Martensitic	-	1.4542	X5CrNiCuNb16-4	S17400	17-4PH
	-	1.4418	X4CrNiMo16-5-1	-	SS2387
	-	1.4122	X39CrMo17-1	-	-
Resulfurised martensitic	C4	1.4005	X12CrS13	S41600	416
	C4	1.4029	X29CrS13	S42020	420F
Ferritic	F1	1.4016	X6Cr17	S43000	430
	F1	1.4511	X3CrNb17	-	430Nb
	F1	1.4113	X6CrMo17-1	S43400	434
	F1	1.4526	X6CrMoNb17-1	S43600	436
	F1	1.4509	X2CrTiNb18	S43940	441
	F1	1.4521	X2CrMoTi18-2	S44400	444
Resulfurised ferritic	-	1.4004	X7CrS17	S43020	430F
	-	1.4104	X14CrMoS17	S43020	430F
Duplex	D2	1.4482	X2CrMnNiMoN21-5-3	S32001	2001
	D2	1.4362	X2CrNiN23-4	S32304	2304
	D4	1.4162	X2CrMnNiN21-5-1	S32101	2101
	D4	1.4062	X2CrNiN22-2	S32202	2202
	D6	1.4462	X2CrNiMoN22-5-3	S31803, S32205	31803, 2205
	D6	1.4481	X2CrNiMoN25-7-3	S31260	SUS329J4L
	D8	1.4410	X2CrNiMoN25-7-4	S32750	2507
	D8	1.4501	X2CrNiMoCuWN25-7-4	S32760	Zeron 100
	D8	1.4507	X2CrNiMoCuN25-6-3	S32520	Ferralium

ISO 3506-1 Chemical composition

Stainless steel grade		Chemical composition a (cast analysis, mass fractionin %) b										Other elements and notes
		C	Si	Mn	P	S	Cr	Mo	Ni	Cu	N
Austenitic	A1	0,12	1,00	6,5	0,020	0,15 to 0,35	16,0 to 19,0	70	5,0 to 10,0	1,75 to 2,Z5	-	c,d,e
	A2	0,10	1,00	2,00	0,050	0,030	15,0 to 20,0	_ f	8,0 to 19,0	4,0	-	g,h
	A3	0,08	1,00	2,00	0,045	0,030	17,0 to 19,0	_ f	9,0 to 12,0	1,00	-	5C ≤ Ti ≤ 0,80 and/or 10C ≤ Nb ≤ 1,00
	A4	0,08	1,00	2,00	0,045	0,030	16,0 to 18,5	2,00 to 3,00	10,0 to 15,0	4,0	-	h,i
	A5	0,08	1,00	2,00	0,045	0,030	16,0 to 18,5	2,00 to 3,00	10,5 to 14,0	1,00	-	5C ≤ Ti ≤ 0,80 and/or 10C ≤ Nb ≤ 1,00 i
	A8	0,030	1,00	2,00	0,040	0,030	19,0 to 22,0	6,0 to 7,0	17,5 to 26,0	1,50	-	-
Martensitic	C1	0,09 to 0,15	1,00	1,00	0,050	0,030	11,5 to 14,0	-	1,00	-	-	i
	C3	0,17 to 0,25	1,00	1,00	0,040	0,030	16,0 to 18,0	-	1,50 to 2,50	-	-	-
	C4	0,08 to 0,15	1,00	1,50	0,060	0,15 to 0,35	12,0 to 14,0	6,0	1,00	-	-	c,i
Ferritic	F1	0,08	1,00	1,00	0,040	0,030	15,0 to 18,0	_ f	1,00	-	-	j
Duplex	D2	0,040	1,00	6,0	0,040	0,030	19,0 to 24,0	0,10 to 1,00	1,50 to 5,5	3,00	0,05 to 0,20	Cr + 3,3Mo +16N ≤ 24,0 k
	D4	0,040	1,00	6,0	0,040	0,030	21,0 to Z5,0	0,10 to 2,00	1,00 to 5,5	3,00	0,05 to 0,30	24,0 < Cr + 3,3Mo + 16N k
	D6	0,030	1,00	2,00	0,040	0,015	21,0 to 23,0	2,50 to 3,5	4,5 to 6,5	-	0,08 to 0,35	-
	D8	0,030	1,00	2,00	0,035	0,015	24,0 to 26,0	3,00 to 4,5	6,0 to 8,0	2,50	0,20 to 0,35	W ≤ 51,00
a According to material standards, values are maximum unless otherwise indicated and the number of digits shown is in accordance with usual rules, see e.g. EN 10088 (all parts). b In case of dispute, product analysis applies. c Selenium can be used to replace sulphur, however restrictions may apply to its use. d If the nickel content is below 8,0 %, the minimum manganese content shall be 5,0 %. e There is no minimum limit to the copper content provided that the nickel content is greater than 8,0 %. f Molybdenum may be present at the discretion of the manufacturer. However, if for some applications limiting of the molybdenum content is essential, this shall be stated at the time of ordering by the purchaser. g If the chromium content is below 17,0 %, the minimum nickel content should be 12,0 %. h For austenitic stainless steels having a maximum carbon content of 0,030 %, nitrogen may be present but shall not exceed 0,22 %. i At the discretion of the manufacturer the carbon content may be higher as necessary in order to obtain the specified mechanical properties for larger diameters, but shall not exceed 0,12 % for austenitic steels. j Titanium and/or niobium may be included to improve corrosion resistance. k This formula is used solely for the purpose of classifying duplex steels in accordance with this document (it is not intended to be used as a selection criterion for corrosion resistance).

ISO 3506-1 Mechanical properties

Mechanical properties (Austenitic and Duplex Steel)

Stainless steel grade		Property class	Tensile strength a Rmf min. MPa	Stress at 0,2 % non-proportional elongation b Rpf mm. MPa	Elongation after fracture A min. mm
Austenitic	A1 A2 A3	50	500	210	0,6d
		70	700	450	0,4d
		80	800	600	0,3d
	A4 A5	50	500	210	0,6d
		70	700	450	0,4d
		80	800	600	0,3d
		100	1000	800	0,2d
	A8	70	700	450	0,4d
		80	800	600	0,3d
		100	1000	800	0,2d
Duplex	D2  D4 D6 D8	70	700	450	0,4d
		80	800	600	0,3d
		100	1000	800	0,2d
a Minimum ultimate tensile loads (Fmf) are specified in Table 4 for coarse pitch thread, and in Table 6 for fine pitch thread. b Minimum loads at Rpf (Fpf) are specified in Table 5 for coarse pitch thread, and in Table 7 for fine pitch thread.

Mechanical properties (Martensitic and Ferritic Steel)

Stainless steel grade		Property class	Tensile strength a Rmr min. MPa	Stress at 0,2 % non-proportional elongation b Rpr mm. MPa	Elongation after fracture A min. mm	Hardness min. to max.
						HV	HRC	HBW
Martensitic	C1	50	500	250	0,2d	155 to 220	-	147 to 209
		70	700	410	0,2d	220 to 330	20 to 34	209 to 314
		110 c	1100	820	0,2d	350 to 440	36 to 45	-
	C3	80	800	640	0,2d	240 to 340	21 to 35	228 to 323
	C4	50	500	250	0,2d	155 to 220	-	147 to 209
		70	700	410	0,2d	220 to 330	20 to 34	209 to 314
Ferritic	F1d	45	450	250	0,2d	135 to 220	-	128 to 209
		60	600	410	0,2d	180 to 285	-	171 to 271
a Minimum ultimate tensile loads (Fmf) are specified in Table 4 for coarse pitch thread, and in Table 6 for fine pitch thread. b Minimum loads at Rpf (Fpf) are specified in Table 5 for coarse pitch thread, and in Table 7 for fine pitch thread. c Hardened and tempered at a minimum tempering temperature of 275 °C. d Only for nominal thread diameters d ≤ 24 mm.

Minimum ultimate tensile loads - Coarse pitch thread

Thread d	Nominal stress area As,nom mm 2	Minimum ultimate tensile  load, Fmf a N
		Austenitic and duplex steels				Martensitic steels				Ferritic steels
		50 b	70	80	100	50	70	80	110	45	60
M3	5,03	2520	3530	4030	5040	2520	3530	4030	5540	2270	3020
M3,5	6,78	3390	4750	5430	6780	3390	4750	5430	7460	3050	4070
M4	8,78	4390	6150	7030	8780	4390	6150	7030	9660	3960	5270
M5	14,2	7100	9930	11350	14190	7100	9930	11350	15610	6390	8510
M6	20,1	10070	14090	16100	20130	10070	14090	16100	22140	9060	12080
M7	28,9	14430	20210	23090	28860	14430	20210	23090	31750	12990	17320
M8	36,6	18310	25630	29290	36610	18310	25630	29290	40270	16480	21970
M10	58,0	29000	40600	46400	57990	29000	40600	46400	63790	26100	34800
M12	84,3	42140	58990	67420	84270	42140	58990	67420	92700	37920	50560
M14	115	57720	80810	92360	115500	57720	80810	92360	127000	51950	69270
M16	157	78340	109700	125400	156700	78340	109700	125400	172400	70510	94010
M18	192	96240	134800	154000	192500	96240	134800	154000	211800	86620	115500
M20	245	122400	171400	195900	244800	122400	171400	195900	269300	110200	146900
M22	303	151700	212400	242800	303400	151700	212400	242800	333800	136600	182100
M24	353	176300	246800	282100	352600	176300	246800	282100	387800	158700	211600
M27	459	229800	321600	367600	459500	229800	321600	367600	505400	-	-
M30	561	280300	392500	448500	560600	280300	392500	448500	616700	-	-
M33	694	346800	485500	554900	693600	346800	485500	554900	763000	-	-
M36	817	408400	571800	653400	816800	408400	571800	653400	898400	-	-
M39	976	487900	683100	780700	975800	487900	683100	780700	1073400	-	-
a Fmf values have been calculated from the exact figures of As,nom as specified in 9.1.5 and rounded to the next upper 10 N up to 100 000 N, and to the next 100 N above. b Property class 50 refers to the austenitic grades A1 to A5 only.

Minimum loads at Rpf - Coarse pitch thread

Thread d	Nominal stress area As,nom mm2	Minimum load at 0,2 % non-proportional  elongation, Fpf a N
		Austenitic and duplex steels				Martensitic steels				Ferritic steels
		50 b	70	80	100	50	70	80	110	45	60
M3	5,03	1060	2270	3020	4030	1260	2070	3220	4130	1260	2070
M3,5	6,78	1430	3050	4070	5430	1700	2780	4340	5560	1700	2780
M4	8,78	1850	3960	5270	7030	2200	3600	5620	7200	2200	3600
M5	14,2	2980	6390	8510	11350	3550	5820	9080	11630	3550	5820
M6	20,1	4230	9060	12080	16100	5040	8260	12880	16510	5040	8260
M7	28,9	6070	12990	17320	23090	7220	11840	18480	23670	7220	11840
M8	36,6	7690	16480	21970	29290	9160	15010	23430	30020	9160	15010
M10	58,0	12180	26100	34800	46400	14500	23780	37120	47560	14500	23780
M12	84,3	17700	37920	50560	67420	21070	34550	53940	69100	21070	34550
M14	115	24250	51950	69270	92360	28860	47340	73890	94670	28860	47340
M16	157	32910	70510	94010	125400	39170	64240	100300	128500	39170	64240
M18	192	40420	86620	115500	154000	48120	78920	123200	157900	48120	78920
M20	245	51410	110200	146900	195900	61200	100400	156700	200800	61200	100400
M22	303	63720	136600	182100	242800	75850	124400	194200	248800	75850	124400
M24	353	74030	158700	211600	282100	88130	144600	225700	289100	88130	144600
M27	459	96480	206800	275700	367600	114900	188400	294100	376800	-	-
M30	561	117800	252300	336400	448500	140200	229900	358800	459700	-	-
M33	694	145700	312100	416200	554900	173400	284400	443900	568800	-	-
M36	817	171600	367600	490100	653400	204200	334900	522800	669800	-	-
M39	976	205000	439100	585500	780700	244000	400100	624500	800200	-	-
a Fpf values have been calculated from the exact figures of As,nom as specified in 9.1.5 and rounded to the next upper 10 N up to 100 000 N, and to the next 100 N above. b Property class 50 refers to the austenitic grades A1 to A5 only

Minimum ultimate tensile loads - Fine pitch thread

Thread dxP	Nominal stress area As,nom mm2	Minimum ultimate tensile load, Fmr a N
		Austenitic and duplex steels				Martensitic steels				Ferritic steels
		50 b	70	80	100	50	70	80	110	45	60
M8x1	39,2	19590	27420	31340	39170	19590	27420	31340	43090	17630	23510
M10x1,25	61,2	30600	42840	48960	61200	30600	42840	48960	67320	27540	36720
M10x1	64,5	32250	45150	51600	64500	32250	45150	51600	70950	29030	38700
M12x1,5	88,1	44070	61690	70510	88130	44070	61690	70510	96940	39660	52880
M12x1,25	92,1	46040	64460	73660	92080	46040	64460	73660	101300	41440	55250
M14x1,5	125	62280	87190	99640	124600	62280	87190	99640	137100	56050	74730
M16x1,5	167	83630	117100	133800	167300	83630	117100	133800	184000	75270	100400
M18x1,5	216	108200	151400	173000	216300	108200	151400	173000	237900	97310	129800
M20x2	258	129000	180600	206400	258000	129000	180600	206400	283800	116100	154800
M20x1,5	272	135800	190100	217300	271600	135800	190100	217300	298700	122200	163000
M22x1,5	333	166600	233200	266500	333100	166600	233200	266500	366400	149900	199900
M24x2	384	192300	269100	307600	384500	192300	269100	307600	422900	173000	230700
M27x2	496	247900	347100	396600	495800	247900	347100	396600	545400	-	-
M30x2	621	310700	434900	497000	621300	310700	434900	497000	683400	-	-
M33x2	761	380400	532600	608700	760800	380400	532600	608700	836900	-	-
M36x3	865	432500	605500	692000	865000	432500	605500	692000	951500	-	-
M39x3	1030	514200	719900	822800	1028400	514200	719900	822800	1131300	-	-
a Fmf have been calculated from the exact figures of As,nom as specified in 9.1.5 and rounded to the next upper 10 N up to 100 000 N, and to the next 100 N above. b Property class 50 refers to the austenitic grades A1 to A5 only.

Minimum loads at Rpf - Fine pitch thread

Thread d xP	Nominal stress area As,nom mm2	Minimum ultimate tensile load, Fmr a N
		Austenitic and duplex steels				Martensitic steels				Ferritic steels
		50 b	70	80	100	50	70	80	110	45	60
M8x1	39,2	8230	17630	23510	31340	9800	16060	25070	32120	9800	16060
M10x1,25	61,2	12860	27540	36720	48960	15300	25100	39170	50190	15300	25100
M10x1	64,5	13550	29030	38700	51600	16130	26450	41280	52890	16130	26450
M12x1,5	88,1	18510	39660	52880	70510	22040	36140	56410	72270	22040	36140
M12x1,25	92,1	19340	41440	55250	73660	23020	37750	58930	75500	23020	37750
M14x1,5	125	26160	56050	74730	99640	31140	51070	79710	102200	31140	51070
M16x1,5	167	35130	75270	100400	133800	41820	68580	107100	137200	41820	68580
M18x1,5	216	45410	97310	129800	173000	54060	88660	138400	177400	54060	88660
M20x2	258	54180	116100	154800	206400	54180	116100	154800	211600	54180	116100
M20x1,5	272	57020	122200	163000	217300	67880	111400	173800	222700	67880	111400
M22x1,5	333	69950	149900	199900	266500	83270	136600	213200	273200	83270	136600
M24x2	384	80730	173000	230700	307600	96110	157700	246100	315300	96110	157700
M27x2	496	104200	223100	297500	396600	124000	203300	317300	406600	-	-
M30x2	621	130500	279600	372800	497000	155400	254700	397600	509400	-	-
M33x2	761	159800	342400	456500	608700	190200	312000	487000	623900	-	-
M36x3	865	181700	389300	519000	692000	216300	354700	553600	709300	-	-
M39x3	1030	216000	462800	617100	822800	257100	421700	658200	843300	-	-
a Fpf have been calculated from the exact figures of As,nom as specified in 9.1.5 and rounded to the next upper 10 N up to 100 000 N, and to the next 100 N above. b Property class 50 refers to the austenitic grades A1 to A5 only.

Minimum breaking torque MB for austenitic grades

Thread d	Minimum breaking torque a MB Nm
	Property class
	50	70	80
Ml,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	18
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
a The drive and/or recess of the fastener are not always able to apply the minimum breaking torque specified in this table; this shall not be the cause for rejection.

Applicability of tests for fasteners with full loadability

Stainless steel grade	Property and related test method
	Minimum tensile strength Rmr		Stress at 0,2 % non-proportional elongation Rpf	Elongation after fracture A	Minimum breaking torque M B	Hardness
	Tensile test 9.1	Wedge tensile test 9.4	Tensile test 9.1	Tensile test 9.1	Torsional test 9.5	Hardness test 9.6
Al  A2 A3 A4  A5  A8	d ≥ 3 mm I ≥ 2,Sd b ≥ 2d	Not relevant	d ≥ 3 mm I ≥ 2,Sd b ≥ 2d	d ≥ 3 mm I ≥ 2,Sd b ≥ 2 d	For all lengths when d < 3 mm; only for lengths I < 2,Sd when d ≥ 3 mm b ≥ ld + 2 P No value available for property  class 100 or for fine pitch  thread	Not applicable
C1  C3  C4	d ≥ 3 mm I ≥ 2,Sd b ≥ 2d	d ≥ 3 mm I ≥ 2,Sd b ≥ 2d	d ≥ 3 mm I ≥ 2,Sd b ≥ 2d	d ≥ 3 mm I ≥ 2,Sd b ≥ 2d	No value available	Applicable
F1	d ≥ 3 mm I ≥ 2,Sd b ≥ 2d	Not relevant	d ≥ 3 mm I ≥ 2,Sd b ≥ 2d	d ≥ 3 mm I ≥ 2,Sd b ≥ 2d	No value available	Applicable
D2 D4 D6  D8	d ≥ 3 mm I ≥ 2,Sd b ≥ 2d	Not relevant	d ≥ 3 mm I ≥ 2,Sd b ≥ 2d	d ≥ 3 mm I ≥ 2,Sd b ≥ 2d	No value available	Not applicable
Notes	a ,b	b,c	a,b	a ,b	c	-
a For fully threaded studs, total length lt ≥ 3,5d. b For l < 2,5d (or lt < 3,5d for fully threaded studs), testing and test conditions shall be agreed between the purchaser and the manufacturer. c Only for bolts and screws (not for studs)

Applicability of tests for fasteners with reduced loadability

Stainless steel grade	Property and related test method
	Minimum tensile strength Rmr	Stress at 0,2 % non-proportional elongation Rpf	Elongation after fracture A	Minimum tensile  load Fmr	Hardness
	Tensile test 9.1, 9.3	Tensile test 9.1	Tensile test 9.1	Tensile test 9.2	Hardness test 9.6
Al A2 A3 A4 A5 A8	d ≥ 3 mm for all lengths, when b ≥ 3d a			d ≥ 3 mm for all  lengths	Not applicable
C1 C3 C4					Applicable
F1					Applicable
D2 D4 D6 D8					Not applicable
a A nominal thread length of at least 3d is necessary to carry out the tensile test in accordance with Figure 2 d), i.e. 1d of free threaded length and additional 1d of engaged threads at both ends.

Wedge angle α for tensile test under wedge loading

Nominal thread diameter d mm	Bolts and screws with unthreaded shank length l s ≥ 2d	Screws threaded to the head Bolts and screws with u nthreaded shank length l s < 2d
	α ± 30'
3 ≤ d ≤ 20	10°	6°
20 < d ≤ 39	6°	4°

ISO 3506-1 Property Class Marking

Property class	Marking
ISO 3506-1 Class 45	TB 45
ISO 3506-1 Class 50	TB 50
ISO 3506-1 Class 60	TB 60
ISO 3506-1 Class 70	TB 70
ISO 3506-1 Class 80	TB 80
ISO 3506-1 Class 100	TB 100
ISO 3506-1 Class 110	TB 110

ISO 3506-1 Heat Treatment

ISO 3506-1 Fasteners of grades and property classes C1-70, C3-80 and C4-70 shall be quenched and tempered.
ISO 3506-1 Fasteners of grade and property class C1-110 shall be quenched and tempered, with a minimum tempering temperature of 275 °C.

ISO 3506-1 Bolting Surface Treatment Specifications