Rodasteel Corporation
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Screws and bolts 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 (Rm) expressed in MPa, while the second represents the ratio between the yield strength ReL (or the specific characteristic proof stress Rp0.2) and the tensile strength Rm 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 classMaterial and heat treatmentChemical composition (analysis on the product) %Minimum hardening temperature °C
CPSB
minmaxmaxmaxmax
4.6(1)Carbon steel-0,550,0500,060Not specified-
4.8(1)0,130,550,0500,060
5.6-0,550,0500,060
5.8(1)
6.8(1)0,150,550,0500,060
8.8(2)(3)Carbon or alloy steel (B, Mn, Cr), quenched and tempered0,15(3)0,400,0250,0250,003425
Quenched and tempered carbon steel0,250,550,0250,025
Quenched and tempered alloy steel0,200,550,0250,025
9.8(2)(3)Carbon or alloy steel (B, Mn, Cr), quenched and tempered0,15(3)0,400,0250,0250.003425
Quenched and tempered carbon steel0,250,550,0250,025
Quenched and tempered alloy steel0,200,550,0250,025
10.9(3)Carbon or alloy steel (B, Mn, Cr), quenched and tempered0,20(3)0,550,0250,0250,003425
Quenched and tempered carbon steel0,250,550,0250,025
Quenched and tempered alloy steel0,200,550,0250,025
12.9(4)Quenched and tempered alloy steel0,300,500,0250,0250,003425
12.9(4)Quenched and tempered carbon steel with the addition of Cr, B, Mn, Mo0,280,500,0250,0250,003380

(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)

CharacteristicsStrength class
4.64.85.65.86.88.8
d≤16mm
8.8
d>16mm
9.810.912.9
Tensile strength
Rm (MPa)
nom40040050050060080080090010001200
min40042050052060080083090010401220
Yield strength Rm (MPa)
ReL up to 6.8 - Rp0,2 from 8.8
nom240-300--6406407209001080
min240-300--6406607209401100
Elongation after fracture, a%min22-20--12121098
Necking Z%      5252484844
Vickers hardness (HV)
F ≥ 98 N
min120130155160190250255290320385
max220220220220250320335360380435
Brinell hardness (HB)
F = 30D2
min114124147152181238242276304314
max209209209209238304318342361414
Rockwell hardness
HRB up to 6.8 - HRC from 8.8
min67717982892223283239
max9595959599,53234373944
Resilience KV (J) – 20°C(1)min--27--2727272727

(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 classesProduction methodsThread diameterExamples of material used
4.6Chip removal≤3911SMn30 - Led108 - Telby - AVZ(1) - PS113(1) - TelbyPlus (1) - Telyx(1)
Cold deformation≤39SB4 – CB10FFS
4.8Chip removal≤3911SMn30 - Led108 - Telby - AVZ(1) - PS113(1) - TelbyPlus (1) - Telyx(1)
Cold deformation≤39SB4 – CB10FFS
5.6Chip removal≤15SB4
Cold deformation≤39CB10FFS
5.8Chip removal≤3011SMn30 - Led108 - Telby - AVZ(1) - PS113(1) - TelbyPlus (1) - Telyx(1)
Cold deformation≤15SB4
≤39C20 - CB10FFS
6.8Chip removal≤16PR60
≤39PR80 – PR38 – 35S20 – 45S20
Cold deformation≤13CB 10 FF S(2) - C20(2)
8.8Chip removal≤2634CrS4
≤39RK1 Pb(1) C40 Pb(2)
Cold deformation≤2634Cr4
≤32Rk1 - RD6 - RK4 - 37CrS4 - 51CrV4
9.8Chip removal≤1634CrS4 - 37CrS4
Cold deformation≤1634CrS4 - 37CrS4
10.9Chip removal≤2234CrS4 - 37CrS4
≤39RK1 Pb(1)
Cold deformation≤2234Cr4 - 37CrS4
≤27RD6 - RK4 - 37CrS4
≤39RK1 – RB2 - 51CrV4 - 34CrNiMo6
12.9Chip removal≤28RK1 - 51CrV4
≤30RB2
Cold deformation≤28RK1 - 51CrV4
≤30RB2 - 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