Standards and tables

Carbon and alloy steel for the production of screws and bolt Non-stainless

Non-stainless screws compliant with the standard EN ISO 898-1:2013 are subdivided into resistance classes and identified by a symbol consisting of two numbers: the first represents the hundredth part of the nominal value of the tensile strength (R_m) expressed in MPa, while the second represents the ratio between the yield strength R_eL (or the specific characteristic proof stress R_p0.2) and the tensile strength R_m multiplied by ten.
Reference is made to the European standard in this section. The steels listed in the section “American steels compliant with the ASTM standards” must be used for the production of screws and bolts according to the ASTM standards.

Chemical composition (%) (EN ISO 898-1:2013)

Strength class	Material and heat treatment	Chemical composition (analysis on the product) %					Minimum hardening temperature °C
		C		P	S	B
		min	max	max	max	max
4.6⁽¹⁾	Carbon steel	-	0,55	0,050	0,060	Not specified	-
4.8⁽¹⁾		0,13	0,55	0,050	0,060
5.6		-	0,55	0,050	0,060
5.8⁽¹⁾		-	0,55	0,050	0,060
6.8⁽¹⁾		0,15	0,55	0,050	0,060
8.8⁽²⁾⁽³⁾	Carbon or alloy steel (B, Mn, Cr), quenched and tempered	0,15⁽³⁾	0,40	0,025	0,025	0,003	425
	Quenched and tempered carbon steel	0,25	0,55	0,025	0,025
	Quenched and tempered alloy steel	0,20	0,55	0,025	0,025
9.8⁽²⁾⁽³⁾	Carbon or alloy steel (B, Mn, Cr), quenched and tempered	0,15⁽³⁾	0,40	0,025	0,025	0.003	425
	Quenched and tempered carbon steel	0,25	0,55	0,025	0,025
	Quenched and tempered alloy steel	0,20	0,55	0,025	0,025
10.9⁽³⁾	Carbon or alloy steel (B, Mn, Cr), quenched and tempered	0,20⁽³⁾	0,55	0,025	0,025	0,003	425
	Quenched and tempered carbon steel	0,25	0,55	0,025	0,025
	Quenched and tempered alloy steel	0,20	0,55	0,025	0,025
12.9⁽⁴⁾	Quenched and tempered alloy steel	0,30	0,50	0,025	0,025	0,003	425
12.9⁽⁴⁾	Quenched and tempered carbon steel with the addition of Cr, B, Mn, Mo	0,28	0,50	0,025	0,025	0,003	380

⁽¹⁾ For these classes it is possible to use free-cutting steel with maximum values of S=0.34%, P=0.11%, Pb=0.35%
⁽²⁾ In order to obtain sufficient temperability with the nominal diameters >20 mm, it may be necessary to use steels of the 10.9 class
⁽³⁾ In the case of carbon steels alloyed with boron with C < 0.25, the manganese must be ≥ 0.6% for the strength class 8.8 and ≥ 0.7% for the strength classes 9.8 and 10.9
⁽⁴⁾ The class 12.9 differs from 10.9 for the different minimum hardening temperature

Mechanical characteristics (EN ISO 898-1:2013)

Characteristics		Strength class
Characteristics		4.6	4.8	5.6	5.8	6.8	8.8 d≤16mm	8.8 d>16mm	9.8	10.9	12.9
Tensile strength R_m (MPa)	nom	400	400	500	500	600	800	800	900	1000	1200
Tensile strength R_m (MPa)	min	400	420	500	520	600	800	830	900	1040	1220
Yield strength Rm (MPa) R_eL up to 6.8 - R_p0,2 from 8.8	nom	240	-	300	-	-	640	640	720	900	1080
Yield strength Rm (MPa) R_eL up to 6.8 - R_p0,2 from 8.8	min	240	-	300	-	-	640	660	720	940	1100
Elongation after fracture, a%	min	22	-	20	-	-	12	12	10	9	8
Necking Z%							52	52	48	48	44
Vickers hardness (HV) F ≥ 98 N	min	120	130	155	160	190	250	255	290	320	385
Vickers hardness (HV) F ≥ 98 N	max	220	220	220	220	250	320	335	360	380	435
Brinell hardness (HB) F = 30D²	min	114	124	147	152	181	238	242	276	304	314
Brinell hardness (HB) F = 30D²	max	209	209	209	209	238	304	318	342	361	414
Rockwell hardness HRB up to 6.8 - HRC from 8.8	min	67	71	79	82	89	22	23	28	32	39
Rockwell hardness HRB up to 6.8 - HRC from 8.8	max	95	95	95	95	99,5	32	34	37	39	44
Resilience KV (J) – 20°C⁽¹⁾	min	-	-	27	-	-	27	27	27	27	27

⁽¹⁾Applicable for diameters ≥ 16 mm

Examples of usable materials
As an example, some materials commonly used for the production of screws according to different production processes are provided, with reference to the standard EN ISO 898-1:2013. The mechanical characteristics depend on the type of screw produced and on the way it which it was made. The examples reported regard the European standard ISO 898-1:99.

Strength classes	Production methods	Thread diameter	Examples of material used
4.6	Chip removal	≤39	11SMn30 - Led108 - Telby - AVZ⁽¹⁾ - PS113⁽¹⁾ - TelbyPlus ⁽¹⁾ - Telyx⁽¹⁾
4.6	Cold deformation	≤39	SB4 – CB10FFS
4.8	Chip removal	≤39	11SMn30 - Led108 - Telby - AVZ⁽¹⁾ - PS113⁽¹⁾ - TelbyPlus ⁽¹⁾ - Telyx⁽¹⁾
4.8	Cold deformation	≤39	SB4 – CB10FFS
5.6	Chip removal	≤15	SB4
5.6	Cold deformation	≤39	CB10FFS
5.8	Chip removal	≤30	11SMn30 - Led108 - Telby - AVZ⁽¹⁾ - PS113⁽¹⁾ - TelbyPlus ⁽¹⁾ - Telyx⁽¹⁾
	Cold deformation	≤15	SB4
	Cold deformation	≤39	C20 - CB10FFS
6.8	Chip removal	≤16	PR60
	Chip removal	≤39	PR80 – PR38 – 35S20 – 45S20
	Cold deformation	≤13	CB 10 FF S⁽²⁾ - C20⁽²⁾
8.8	Chip removal	≤26	34CrS4
	Chip removal	≤39	RK1 Pb⁽¹⁾ C40 Pb⁽²⁾
	Cold deformation	≤26	34Cr4
	Cold deformation	≤32	Rk1 - RD6 - RK4 - 37CrS4 - 51CrV4
9.8	Chip removal	≤16	34CrS4 - 37CrS4
9.8	Cold deformation	≤16	34CrS4 - 37CrS4
10.9	Chip removal	≤22	34CrS4 - 37CrS4
	Chip removal	≤39	RK1 Pb⁽¹⁾
	Cold deformation	≤22	34Cr4 - 37CrS4
		≤27	RD6 - RK4 - 37CrS4
		≤39	RK1 – RB2 - 51CrV4 - 34CrNiMo6
12.9	Chip removal	≤28	RK1 - 51CrV4
	Chip removal	≤30	RB2
	Cold deformation	≤28	RK1 - 51CrV4
	Cold deformation	≤30	RB2 - 34CrNiMo6

⁽¹⁾ Materials that, while not completely satisfying the standard, are frequently used upon agreement between the producer and user of the screws
⁽²⁾ Materials that can only satisfy the characteristics in the drawn state

Carbon and alloy steel for the production of screws and bolt Non-stainless

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