ISO 898 PART 1 (EXTRACT)

ISO 898 PART 1 – 2013 (EXTRACT)

Mechanical properties of fasteners made of carbon steel and alloy steel — Part 1: Bolts, screws and studs with specified property classes — Coarse thread and fine pitch thread ISO 898-1:2013 specifies mechanical and physical properties of bolts, screws and studs made of carbon steel and alloy steel when tested at an ambient temperature range of 10°C to 35°C. Fasteners (the term used when bolts, screws and studs are considered all together) that conform to the requirements of ISO 898-1:2013 are evaluated at that ambient temperature range. They might not retain the specified mechanical and physical properties at elevated temperatures (see Annex B) and/or lower temperatures. Certain bolts and screws might not fulfil the tensile or torsional requirements of ISO 898-1:2013 because the geometry of their heads reduces the shear area in the head compared to the stress area in the thread. These include bolts and screws having a low or countersunk head.

ISO 898-1:2013 is applicable to bolts, screws and studs

made of carbon steel or alloy steel,
having triangular ISO metric screw thread in accordance with ISO 68-1,
with coarse pitch thread M1,6 to M39, and fine pitch thread M8x1 to M39x3,
with diameter/pitch combinations in accordance with ISO 261 and ISO 262, and
having thread tolerances in accordance with ISO 965-1, ISO 965-2 and ISO 965-4.

It is not applicable to set screws and similar threaded fasteners not under tensile stress (see ISO 898-5). It does not specify requirements for such properties as weldability, corrosion resistance resistance to shear stress, torque/clamp force performance (for test method, see ISO 16047), or fatigue resistance

Chemical composition as per ISO 898-1 for typical grades
CLASS	MATERIAL AND TREATMENT	C	C	P	S	B	TEMPERING TEMP. [C]
CLASS	MATERIAL AND TREATMENT	Min	Max	Max	Max	Max	TEMPERING TEMP. [C]
8.8	CARBON STEEL WITH ADDITIVES (E.G. B, MN OR CR) QUENCHED AND TEMPERED	0.15 (D)	0.4	0.025	0.025	0.003	425
8.8	CARBON STEEL QUENCHED AND TEMPERED	0.25	0.55	0.35	0.025	0.003	425
10.9	CARBON STEEL WITH ADDITIVES (E.G. B, MN OR CR) QUENCHED AND TEMPERED	0.15(D)	0.35	0.025	0.025	0.003	340
	CARBON STEEL QUENCHED AND TEMPERED	0.25	0.55	0.025	0.025	0.003	425
	CARBON STEEL WITH ADDITIVES (E.G. B, MN OR CR) QUENCHED AND TEMPERED	0.20 (D)	0.55	0.025	0.025
	ALLOY STEEL QUENCHED AND TEMPERED (G)	0.2	0.55	0.025	0.025
12.9	ALLOY STEEL QUENCHED AND TEMPERED (G)	0.28	0.5 0.025	0.025	0.025	0.003	380

Mechanical properties of screws and studs according to EN ISO 898-1:2013 Property class 4.6 to 12.9.
NO	Mechanical properties	property classes
		4,6	4,8	5,6	5,8	6,8
							8.8	8,8	9,8	10.9	12.9
							d<16 mm	d>16 mm	d<16 mm	10.9	12.9
1	Tensile strength, Rm, MPa	nom. °	400		500		600	800		900	1000	1200
1	Tensile strength, Rm, MPa	min.	400	420	500	520	600	800	830	900	1040	1220
2	Lower proof stress ReL ᵈ, MPa	nom. ᶜ	240	–	300	–	–	–	–	–	–	–
2	Lower proof stress ReL ᵈ, MPa	min.	240	–	300	–	–	–	–	–	–	–
3	Yield strength, Rp0.2, MPa		–	–	–	–	–	640	640	720	900	1080
3	Yield strength, Rp0.2, MPa	min.	–	–	–	–	–	640	660	720	940	1100
4	Yield strength at 0.0048 d for whole screw, Rpf, MPa	nom.	–	320	–	400	480	–	–	–	–	–
4	Yield strength at 0.0048 d for whole screw, Rpf, MPa	min.	–	340ᵉ	–	420ᵉ	480ᵉ	–	–	–	–	–
5	Proof stress, Spᶠ, MPa	nom.	225	310	280	380	440	580	600	650	830	970
5	Stress during proofing load testing		0,94	0,91	0,93	0,90	0,92	0,91	0,91	0,90	0,88	0,88
6	Elongation after fracture (test specimen), A, %	min.	22	–	20	–	–	12	12	10	9	8
7	Contraction after fracture (test specimen), Z, %	min.	–					52		48	48	44
8	Elongation after fracture, Af (whole screw)	min.	–	0,24	–	0,22	0,20	–	–	–	–	–
9	Ductility in event of head soundness test		Inget brott
10	Vickers hardness, HV	min.	120	130	155	160	190	250	255	290	320	385
10	F ≥ 98 N	max.	220ᵍ				250	320	335	360	380	435
11	Brinell hardness, HBW	min.	114	124	147	152	181	238	242	276	304	366
11	F = 30 D²	max.	209				238	304	318	342	361	414
12	Rockwell hardness, HRB	min.	67	71	79	82	89	–
	Rockwell hardness, HRB	max.	95,0ᵍ				99,5	–
	Rockwell hardness, HRC	min.	–					22	23	28	32	39
	Rockwell hardness, HRC	max.	–					32	34	37	39	44
13	Surface hardness, HV 0.3	max.	–					h			h, i	h, j
14	Min. height of non-decarburised zone,	min.	–					½ H1			⅔ H1	¾ H1
	E, mm	min.	–					½ H1			⅔ H1	¾ H1
	Max.depth of complete decarburisation,	max.	–					0,015
	G, mm	max.	–					0,015
15	Reduction in hardness after re-annealing, HV	max.	–
16	Fracture torque, MB,Nm	min.	–					regarding to ISO 898-7
17	Impact strength, K, J	min.	–		27	–		27	27	27	27	m
18	Surface defects		ISO 6157-1									ISO
18	Surface defects		ISO 6157-1									6157-3

The values do not apply to structural bolts.
For structural bolts ≥ M12.
Nominal values are only specified in order to indicate property class in the designation system.
If the lower proof stress ReL cannot be determined, it is permitted to measure the yield strength Rp0.2.
For property classes 4.8, 5.8 and 6.8, the values for Rpf min are under investigation.
Proof loads are specified in SS-EN ISO 898-1:2013.
GHardness determined at the end of the screw must be max. 250 HV, 238 HB or 99.5 HRB.
The surface hardness may not be more than 30 Vickers units higher than the measured core hardness determined with HV 0.3.
No surface hardness exceeding 390 HV is permitted.
No surface hardness exceeding 435 HV is permitted.

Hardness requirement as per ISO 898-1 for typical grades
HARDNESS SCALE		CLASS 8.8	CLASS 8.8	CLASS 10.9	CLASS 12.9
HARDNESS SCALE		M16 AND BELOW	ABOVE M16	CLASS 10.9	CLASS 12.9
VICKERS, HV	MIN.	250	255	320	385
VICKERS, HV	MAX.	320	335	380	435
BRINELL, HB	MIN.	238	242	304	366
BRINELL, HB	MAX.	304	318	361	414
ROCKWELL, HRC	MIN.	22	23	32	39
ROCKWELL, HRC	MAX.	32	34	39	44

ISO 898 PART 1 (EXTRACT)

ISO 898-1:2013 is applicable to bolts, screws and studs

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