IS 1367 grade 12.9

IS 1367 Grades

Mechanical properties of fasteners made of carbon steel and alloy steel As Per IS 1367 Gr. - 12.9

Bolts, screws and studs with specified property classes — coarse thread and fine pitch thread

The IS 1367 Grade 8.8 specification covers carbon steel bolts and studs ranging from M-6 to M-39 diameter. We use high carbon steel material and high alloy steel raw materials to achieve the required properties in this standard. There are three popular grades in this standard, 8.8 , 10.9 and 12.9 which denote material hardness strength and their respective mechanical properties. Refer to the Mechanical Properties Chart for the subtle Strength differences within each grade.

IS 1367 Grade 12.9
12.9 Socket head cap screws, Allen bolts
IS 1367 grade 12.9 Chemical properties

Property class

Material and heat treatment

Chemical composition limit (cast analysis, %)a

Tempering temperature ⁰C

Min.

C

P

S

Bb

min.

max.

max.

max.

max.

12.9

Alloy steel quenched and temperedg

0,30

0,50

0,025

0,025

0,003

425

12.9

Carbon steel with additives (e.g. Boron or Mn or Cr or Molybdenum) quenched and tempered

0,28

0,50

0,025

0,025

0,003

380

IS 1367 grade 12.9 Mechanical properties

Mechanical or physical property

Tensile strength, Rm, MPa

Stress at 0,2 % non-proportional elongation, Rp0,2, MPa

Stress under proof load, Spf, MPa

Proof strength ratio

Sp,nom/ReL,min

Percentage elongation after fracture for machined test pieces, A, %

Percentage reduction of area after fracture for machined test pieces, Z, %

Height of non-decarburized thread zone, E, mm

Depth of complete decarburization in the thread, G, mm

Reduction of hardness after retempering, HV

Impact strength, KVij, J

nom.c

min.

nom.c

min.

nom.

min

min.

min.

min.

max.

max.

min.

12.9

1 200

1220

1080

1100

970

0,88

8

44

3/4 H1

0,018

23

k

IS 1367 grade 12.9 Recommended hardness

Mechanical or physical property

Vickers hardness,

HV F 98 N

Brinell hardness, HBW F = 30 D2

Rockwell hardness, HRC

Surface hardness, HV 0,3

min.

max.

min.

max.

min.

max.

max.

12.9

385

435

380

429

39

44

435