ISO 898-2

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Home
About
Product
Product

Adfast Components offers precision-engineered hot and cold forged fasteners ranging from M3 to M100, ensuring superior strength and reliability. Designed to meet diverse industrial standards, our components guarantee durability and performance.

Precision Components

Pumps & Valves

Automobile

Customised

Electronic

Medical

Contract Manufacturing

3D Printing & Additive Manufacturing

Fastener

Bolts

Coated Fasteners

Washer

Stud Bolts

Nuts

Screws
Resources
Resources

Explore Adfast Components for precision-engineered fasteners, offering hot & cold forged solutions with metric sizes from M3 to M100 for diverse industrial needs.

materials

Carbon Steel

Alloy Steel

Stainless Steel

Super Alloys

Non Ferrous Metal & Alloys

High Performance Nickel Alloys

Copper Alloys

Technical

Specification

Standard

Weight

Applications

Threads
Contact

ISO 898-2 Specification

Scope

ISO 898-2 specification concludes mechanical and physical properties of nuts with coarse thread and fine pitch thread made of carbon steel and alloy steel when tested at an ambient temperature range of 10 °C to 35 °C.
Thin Nuts, Regular Nuts & High Nuts conforming to the requirements of ISO 898-2 are evaluated at that ambient temperature range and used in applications ranging from -50 °C to +150 °C. ISO 898-2 specification is applicable for nuts with coarse thread M5 ≤ D ≤ M39, and fine pitch thread M8×1 ≤ D ≤ M39×3 in accordance with diameter/pitch combinations as per ISO 261 and ISO 262.

Related Specifications

Designations

Property class	Range of nominal diameters, D
Property class	Regular nut (style 1)	High nut (style 2)	Thin nut (style 0)
04	–	–	M5 ≤ D ≤ M39 M8×1 ≤ D ≤ M39×3
05	–	–	M5 ≤ D ≤ M39 M8×1 ≤ D ≤ M39×3
5	M5 ≤ D ≤ M39 M8×1 ≤ D ≤ M39×3	–	–
6	M5 ≤ D ≤ M39 M8×1 ≤ D ≤ M39×3	–	–
8	M5 ≤ D ≤ M39 M8×1 ≤ D ≤ M39×3	M5 < D ≤ M39 M8×1 ≤ D ≤ M39×3	–
9	–	M5 ≤ D ≤ M39	–
10	M5 ≤ D ≤ M39 M8×1 ≤ D ≤ M16×1,5	M5 ≤ D ≤ M39 M8×1 ≤ D ≤ M39×3	–
12	M5 ≤ D ≤ M16	M5 ≤ D ≤ M39 M8×1 ≤ D ≤ M16×1,5	–

Combinations

Nut property class	Maximum property class of mating bolt, screw and stud
5	5.8
6	6.8
8	8.8
9	9.8
10	10.9
12	12.9/12.9

Chemical Composition

Thread	Property class		Material and nut heat treatment	Chemical composition limit (cast analysis %)a
Thread	Property class		Material and nut heat treatment	C max.	Mn min.	P max.	S max.
Coarse thread	04^c		Carbon steeld	0,58	0,25	0,060	0,150
	05^c		Carbon steel, QT^e	0,58	0,30	0,048	0,058
	5^b		Carbon steeld	0,58	–	0,060	0,150
	6b		Carbon steeld	0,58	–	0,060	0,150
	8	High nut (style 2)	Carbon steeld	0,58	0,25	0,060	0,150
	8	Regular nut (style 1) D £ M16	Carbon steeld	0,58	0,25	0,060	0,150
	8c	Regular nut (style 1) D > M16	Carbon steel, QT^e	0,58	0,30	0,048	0,058
	9		Carbon steeld	0,58	0,25	0,060	0,150
	10^c		Carbon steel, QT^e	0,58	0,30	0,048	0,058
	12^c		Carbon steel, QT^e	0,58	0,45	0,048	0,058
Fine pitch thread	04b		Carbon steeld	0,58	0,25	0,060	0,150
	05^c		Carbon steel, QT^e	0,58	0,30	0,048	0,058
	5^b		Carbon steeld	0,58	–	0,060	0,150
	6b	D ≤ M16	Carbon steeld	0,58	–	0,060	0,150
	6b	D > M16	Carbon steel; QT^e	0,58	0,30	0,048	0,058
	8	High nut (style 2)	Carbon steeld	0,58	0,25	0,060	0,150
	8c	Regular nut (style 1)	Carbon steel, QT^e	0,58	0,30	0,048	0,058
	10^c		Carbon steel, QT^e	0,58	0,30	0,048	0,058
	12^c		Carbon steel, QT^e	0,58	0,45	0,048	0,058
QT = Quenched and tempered nuts. “-“ No limit specified. a In case of dispute, the product analysis applies. b Nuts of these property classes may be manufactured from free-cutting steel upon agreement between the purchaser and the manufacturer; in such a case, sulfur, phosphorus and lead are permissible with the following maximum contents: S: 0,34 %; P: 0,11 %; Pb: 0,35%. c Alloying elements may be added, provided the mechanical properties required in Clause 7 are fulfilled. d This may be quenched and tempered at the manufacturer’s discretion. e For materials of these property classes, there shall be sufficient hardenability to ensure a structure consisting of approximately 90 % martensite in the “as-hardened” condition before tempering in the threaded area of the nut as specified

Mechanical Properties

Proof loads Coarse
Proof loads fine

Thread D	Pitch P	Proof load a, N Property class
Thread D	Pitch P	04^b	05	5	6	8	9	10	12
M5	0,8	5400	7100	8250	9500	12140	13000	14800	16300
M6	1	7640	10000	11700	13500	17200	18400	20900	23100
M7	1	11000	14500	16800	19400	24700	26400	30100	33200
M8	1,25	13900	18300	21600	24900	31800	34400	38100	42500
M10	1,5	22000	29000	34200	39400	50500	54500	60300	67300
M12	1,75	32000	42200	51400	59000	74200	80100	88500	100300
M14^b	2	43700	57500	70200	80500	101200	109300	120800	136900
M16	2	59700	78500	95800	109900	138200	149200	164900	186800
M18	2,5	73000	96000	121000	138200	176600	176600	203500	230400
M20	2,5	93100	122500	154400	176400	225400	225400	259700	294000
M22	2,5	115100	151500	190900	218200	278800	278800	321200	363600
M24^b	3	134100	176500	222400	254200	324800	324800	374200	423600
M27	3	174400	229500	289200	330500	422300	422300	486500	550800
M30	3,5	213200	280500	353400	403900	516100	516100	594700	673200
M33	3,5	263700	347000	437200	499700	638500	638500	735600	832800
M36	4^b	310500	408500	514700	588200	751600	751600	866000	980400
M39	4^b	370900	488000	614900	702700	897900	897900	1035000	1171000
a For the application of thin nuts, it should be considered that the stripping load is lower than the proof load of a nut with full loadability (see Annex A).

Thread D x P	Proof load a, N Property class
Thread D x P	04^b	05	5	6	8	10	12
M8x1	14900	19600	27000	30200	37400	43100	47000
M10x1,25	23300	30600	44200	47100	58400	67300	73400
M10x1	24500	32200	44500	49700	61600	71000	77400
M12x1,5	33500	44000	60800	68700	84100	97800	105700
M12x1,25	35000	46000	63500	71800	88000	102200	110500
M14x1,5	47500	62500	86300	97500	119400	138800	150000
M16x1,5	63500	83500	115200	130300	159500	185400	200400
M18x2	77500	102000	146900	177500	210100	220300	–
M18x1,5	81700	107500	154800	187000	221500	232200	–
M20x2	98000	129000	185800	224500	265700	278600	–
M20x1,5	103400	136000	195800	236600	280200	293800	–
M22x2	120800	159000	229000	276700	327500	343400	–
M22x1,5	126500	166500	239800	289700	343000	359600	–
M24x2	145900	192000	276500	334100	395500	414700	–
M27x2	188500	248000	351100	431500	510900	535700	–
M30x2	236000	310500	447100	540300	639600	670700	–
M33x2	289200	380500	547900	662100	783800	821900	–
M36x3	328700	432500	622800	804400	942800	934200	–
M39x3	391400	515000	741600	957900	1123000	1112000	–
a For the application of thin nuts, it should be considered that the stripping load is lower than the proof load of a nut with full loadability, see Annex A

Hardness Coarse
Hardness fine
Vickers hardness

Thread D	Property class
	04^b		05		5		6		8		9		10		12
	Vickers hardness, HV
	min.	max.	min.	max.	min.	max.	min.	max.	min.	max.	min.	max.	min.	max.	min.	max.
M5 ≤ D ≤ M16	188	302	272	353	130	302	150	302	200	302	188	302	272	353	295^c	353
M16 < D ≤ M39	188	302	272	353	146	302	170	302	233a	353b	188	302	272	353	272	353
	Brinell hardness, HB
	min.	max.	min.	max.	min.	max.	min.	max.	min.	max.	min.	max.	min.	max.	min.	max.
M5 ≤ D ≤ M16	179	287	259	336	124^b	287	143	287	190	287	179	287	259	336	280c	336
M16 < D ≤ M39	179	287	259	336	139	287	162	287	221a	336b	179	287	259	336	259	336
	Rockwell hardness, HRC
	min.	max.	min.	max.	min.	max.	min.	max.	min.	max.	min.	max.	min.	max.	min.	max.
M5 ≤ D ≤ M16	–	30	26	36	–	30	–	30	–	30	–	30	26	36	29c	36
M16 < D ≤ M39	–	30	26	36	–	30	–	30	–	36b	–	30	26	36	26	36
Surface integrity shall be in accordance with ISO 6157-2. Vickers hardness test is the reference method for acceptance (see 9.2.4). a Minimum value for high nuts (style 2): 180 HV (171 HB). b Maximum value for high nuts (style 2): 302 HV (287 HB; 30 HRC). c Minimum value for high nuts (style 2): 272 HV (259 HB; 26 HRC).

Thread D x P	Property class
	04^b		05		5		6		8		10		12
	Vickers hardness, HV
	min.	max.	min.	max.	min.	max.	min.	max.	min.	max.	min.	max.	min.	max.
M8×1 ≤ D ≤ M16×1,5	188	302	272	353	175	302	188	302	250a	353b	295^c	353	295	353
M16×1,5 < D ≤ M39×3	188	302	272	353	190	302	233	302	295	353	260	353	–	–
	Brinell hardness, HB
	min.	max.	min.	max.	min.	max.	min.	max.	min.	max.	min.	max.	min.	max.
M8×1 ≤ D ≤ M16×1,5	179	287	259	336	166	287	179	287	238a	336b	280c	336	280	336
M16×1,5 < D ≤ M39×3	179	287	259	336	181	287	221	287	280	336	247	336	–	–
	Rockwell hardness, HRC
	min.	max.	min.	max.	min.	max.	min.	max.	min.	max.	min.	max.	min.	max.
M8×1 ≤ D ≤ M16×1,5	–	30	26	36	–	30	–	30	22,2a	36b	29c	36	29	36
M16×1,5 < D ≤ M39×3	–	30	26	36	–	30	–	30	29,2	36	24^b	36	–	–
Surface integrity shall be in accordance with ISO 6157-2. The Vickers hardness test is the reference method for acceptance (see 9.2.4). a Minimum value for high nuts (style 2): 195 HV (185 HB). b Maximum value for high nuts (style 2): 302 HV (287 HB; 30 HRC). c Minimum value for high nuts (style 2): 250 HV (238 HB; 22,2 HRC)

Thread D	Minimum Vickers hardness of nuts HV
	Property class
	5	6	8	10	12
M3	151	178	233	284^b	347
M3,5	157	184^b	240	294^b	357
M4^b	147	174^b	228	277	337

Coating Specifications

Renowned Brands

Dimensions

Property class	4^b	5
Marking symbol	4^b	5

ISO 898-2 Hex Nut Dimensions

Thread D	Width across flats s mm	Minimum height of hexagon nut
		Regular nut (style 1)		High nut (style 2)
		m_min mm	m_min/D	m_min mm	m_min/D
M5	8	4,40	0,88	4,80	0,96
M6	10	4,90	0,82	5,40	0,90
M7	11	6,14^b	0,88	6,84^b	0,98
M8	13	6,44^b	0,81	7,14^b	0,90
M10	16	8,04^b	0,80	8,94^b	0,89
M12	18	10,37	0,86	11,57	0,96
M14^b	21	12,10	0,86	13,40	0,96
M16	24^b	14,10	0,88	15,70	0,98
M18	27	15,10	0,84^b	16,90	0,94^b
M20	30	16,90	0,85	19,00	0,95
M22	34^b	18,10	0,82	20,50	0,93
M24^b	36	20,20	0,84^b	22,60	0,94^b
M27	41	22,50	0,83	25,40	0,94^b
M30	46	24,30	0,81	27,30	0,91
M33	50	27,40	0,83	30,90	0,94^b
M36	55	29,40	0,82	33,10	0,92
M39	60	31,80	0,82	35,90	0,92

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