ISO 898-2 Grade 8

ISO 898-2 Grades

Mechanical properties of Nuts made of carbon steel and alloy steel Grade 8

The Grade 8 Nuts with specified proof load values - coarse thread

The ISO 898-2:2013 Grade 8 specification covers carbon steel nuts ranging from M-6 to M-64 diameter. We use high carbon steel material and high alloy steel raw materials to achieve the required properties of grade 8. There are three popular grades in this standard 8, 10 and 12 which denote material hardness Strength and their respective mechanical properties.

ISO 898-2:2013 Grade 8
8 Hex Nuts, Heavy Hex Nuts, Jam nuts, Lock Nuts & Thin Hex Nuts
ISO 898-2:2013 grade 8 Chemical properties

Property class

Material and heat treatment

Chemical composition limit (cast analysis, %)a

C

P

S

Mn

min.

max.

max.

max.

min.

8

CARBON STEEL QUENCHED AND TEMPERED

-

0.58

0.048

0.058

0.30

ISO 898-2:2013 grade 8 Recommended hardness

Mechanical or physical property

Vickers hardness

HV

Brinell hardness

HB

Rockwell hardness

HRC

min.

max.

min.

max.

min.

max.

M5 ≤ D ≤ M16

200

302

190

287

-

30

M16 < D ≤ M39

233

353

221

336

-

36

ISO 898-2:2013 grade 8Proof load values for nuts with coarse thread

Thread Size (D)

Pitch (P)

Proof Loada (N)

M12

1.75

74200

M14

2

101200

M16

2

138200

M18

2.5

176600

M20

2.5

225400

M22

2.5

278800

M24

3

324800

M27

3

422300

M30

3.5

516100

M33

3.5

638500

M36

4

751600

M39

4

897900