Mechanical and Physical Properties of Carbon and Alloy Steel Bolts, Screws and Studs
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Use this table to determine tensile strength, yield strength, elongation at fracture, head soundness, notch impact strength and hardness of carbon and alloy bolts, screws and studs (coarse and fine thread).
According to EN ISO 898-1
Mechanical or Physical Property | Property Class | ||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|
4.6 | 4.8 | 5.6 | 5.8 | 6.8 | 8.8 | 9.8 | 10.9 | 12.9/ 12.9 | |||
d ≤ | d > | d ≤ | |||||||||
16 mm a | 16 mm b | 16 mm | |||||||||
Tensile strength, Rm, MPa | nom.c | 400 | 500 | 600 | 800 | 900 | 1000 | 1200 | |||
min. | 400 | 420 | 500 | 520 | 600 | 800 | 830 | 900 | 1040 | 1220 | |
Lower yield strength, ReLd, MPa | nom.c | 240 | - | 300 | - | - | - | - | - | - | - |
min. | 240 | - | 300 | - | - | - | - | - | - | - | |
Stress at 0,2 % non-proportional elongation, Rp0,2, MPa | nom.c | - | - | - | - | - | 640 | 640 | 720 | 900 | 1080 |
min. | - | - | - | - | - | 640 | 660 | 720 | 940 | 1100 | |
Stress at 0,0048d non-proportional elongation for full-size fasteners, Rpf, Mpa | nom.c | - | 320 | - | 400 | 480 | - | - | - | - | - |
min. | - | 340 e | - | 420 e | 480 e | - | - | - | - | - | |
Stress under proof load, Spf, MPa | nom. | 225 | 310 | 280 | 380 | 440 | 580 | 600 | 650 | 830 | 970 |
Proof strength ratio | 0,94 | 0,91 | 0,93 | 0,90 | 0,92 | 0,91 | 0,91 | 0,90 | 0,88 | 0,88 | |
Sp,nom/ReL,min | |||||||||||
or Sp,nom/Rp0,2 min or | |||||||||||
Sp,nom/Rpf,min | |||||||||||
Percentage elongation after fracture for machined test pieces, A, % | min. | 22 | - | 20 | - | - | 12 | 12 | 10 | 9 | 8 |
Percentage reduction of area after fracture for machined test pieces, Z, % | min. | - | 52 | 48 | 48 | 44 | |||||
Elongation after fracture for full-size fasteners, Af (see also Annex C) | min. | - | 0,24 | - | 0,22 | 0,20 | - | - | - | - | - |
Head soundness | No fracture | ||||||||||
Vickers hardness, HV F ≥ 98 N | min. | 120 | 130 | 155 | 160 | 190 | 250 | 255 | 290 | 320 | 385 |
max. | 220 g | 250 | 320 | 335 | 360 | 380 | 435 | ||||
Brinell hardness, HBW F = 30 D2 | min. | 114 | 124 | 147 | 152 | 181 | 245 | 250 | 286 | 316 | 380 |
max. | 209 g | 238 | 316 | 331 | 355 | 375 | 429 | ||||
Rockwell hardness, HRB | min. | 67 | 71 | 79 | 82 | 89 | - | ||||
max. | 95,0 g | 99,5 | - | ||||||||
Rockwell hardness, HRC | min. | - | 22 | 23 | 28 | 32 | 39 | ||||
max. | - | 32 | 34 | 37 | 39 | 44 | |||||
Surface hardness, HV 0,3 | max. | - | - | 390 | 435 | ||||||
Non-carburization, HV 0,3 | max. | - | h | h | h | ||||||
Height of non-decarburized thread zone, E, mm | min. | - | 1/2 H1 | 2/3 H1 | 3/4 H1 | ||||||
Depth of complete decarburization in the thread, G, mm | max. | - | 15 | ||||||||
Reduction of hardness after retempering, HV | max. | - | 20 | ||||||||
Breaking torque, MB, Nm | min. | - | in accordance with ISO 898-7 | ||||||||
Impact strength, KV i j, J | min. | - | 27 | - | 27 | 27 | 27 | 27 | k | ||
Surface integrity in accordance with | ISO 6157-1l | ISO 6157-3 |
a Values do not apply to structural bolting.
b For structural bolting d ≥ M12.
c Nominal values are specified only for the purpose of the designation system for property classes. See Clause 5.
d In cases where the lower yield strength, ReL, cannot be determined, it is permissible to measure the stress at 0,2 % non-proportional elongation Rp0,2.
e For the property classes 4.8, 5.8 and 6.8, the values for Rpf,min are under investigation. The values at the time of publication of this part of ISO 898 are given for calculation of the proof stress ratio only. They are not test values.
f Proof loads are specified in Tables 5 and 7.
g Hardness determined at the end of a fastener shall be 250 HV, 238 HB or 99,5 HRB maximum.
h Surface hardness shall not be more than 30 Vickers points above the measured base metal hardness of the fastener when determination of both surface hardness and base metal hardness are carried out with HV 0,3 (see 9.11).
i Values are determined at a test temperature of −20 °C (see 9.14).
j Applies to d ≥ 16 mm.
k Value for KV is under investigation.
l Instead of ISO 6157-1, ISO 6157-3 may apply by agreement between the manufacturer and the purchaser.
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