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.
8.8 | ![]() |
Hex bolts, screws, stud bolts, double ended studs, full thread rods, full threaded studs |
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. |
|||
8.8 |
Carbon steel with additives (e.g. Boron or Mn or Cr) quenched and tempered |
0,15e |
0,40 |
0,025 |
0,025 |
0,003 |
425 |
Carbon steel quenched and tempered |
0,25 |
0,55 |
0,025 |
0,025 |
|||
Alloy steel quenched and temperedg |
0,20 |
0,55 |
0,025 |
0,025 |
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 ratioSp,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. |
max. |
max. |
min. |
|||
8.8 |
d≤ 16 mma |
800 |
800 |
640 |
640 |
580 |
0,91 |
12 |
52 |
1/2 H1 |
0,015 |
20 |
27 |
d> 16 mmb |
830 |
640 |
660 |
600 |
0,91 |
0,016 |
21 |
27 |
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. |
||
8.8 |
D ≤ 16 mma |
250 |
320 |
245 |
316 |
22 |
32 |
- |
D > 16 mmb |
255 |
335 |
250 |
331 |
23 |
34 |
- |
When it comes to securing critical components in demanding environments, our IS 1367 Grade 8.8 bolts represent the pinnacle of fastening technology. These precision-engineered fasteners are designed to provide exceptional strength and reliability in construction, heavy machinery, and industrial applications.
Our IS 1367 Grade 8.8 bolts deliver impressive performance with a minimum tensile strength of 800 MPa and a yield strength of 640 MPa in grade 8.8. This translates to superior load-bearing capacity and structural integrity under significant stress conditions. Regarding IS 1367 bolt dimensions, we offer comprehensive sizing options from M5 through M80, accommodating virtually any engineering requirement.
At Bigboltnut, we utilise premium carbon steel and alloy steels in our manufacturing process, subjecting each bolt to rigorous quenching and tempering heat treatments. This specialised heat treatment optimises the mechanical properties of the fasteners. The precise balance of carbon, manganese, and chromium in our formulation ensures consistent performance characteristics across all production batches, even in the most challenging operational environments.
For enhanced durability, our bolts can be finished with black oxide coating, zinc plating, or hot-dip galvanisation according to your specific requirements. These surface treatments provide substantial protection against corrosion, extending service life in outdoor installations, marine settings, and industrial facilities.
Our product range features diverse fastener configurations, including hex head bolts in both fully and partially threaded designs. We adhere to ISO metric thread styles to ensure optimal compatibility with standard nuts and washers, facilitating efficient assembly and maintenance procedures. At Bigboltnut, quality control remains our foremost priority. Our manufacturing process encompasses comprehensive testing for dimensional accuracy, mechanical properties, and surface integrity, guaranteeing that every fastener meets or exceeds IS 1367 standards. Application Versatility IS 1367 Grade 8.8 bolts demonstrate exceptional reliability in steel structures, industrial equipment, wind energy systems, and automotive applications. Wherever uncompromising fastening integrity is essential, our bolts provide the necessary performance assurance. Technical Considerations Torque specifications: For M16 Grade 8.8 bolts, we recommend approximately 210-230 Nm when installed dry. However, we advise consulting application-specific guidelines for optimal installation parameters. Corrosion protection: Our galvanised options are ideally suited for exposure to environmental elements, with special attention given to
At Bigboltnut, we utilise premium carbon steel and alloy steels in our manufacturing process, subjecting each bolt to rigorous quenching and tempering heat treatments. This specialised heat treatment optimises the mechanical properties of the fasteners. The precise balance of carbon, manganese, and chromium in our formulation ensures consistent performance characteristics across all production batches, even in the most challenging operational environments.
For enhanced durability, our bolts can be finished with black oxide coating, zinc plating, or hot-dip galvanisation according to your specific requirements. These surface treatments provide substantial protection against corrosion, extending service life in outdoor installations, marine settings, and industrial facilities.
Our product range features diverse fastener configurations, including hex head bolts in both fully and partially threaded designs. We adhere to ISO metric thread styles to ensure optimal compatibility with standard nuts and washers, facilitating efficient assembly and maintenance procedures.At Bigboltnut, quality control remains our foremost priority. Our manufacturing process encompasses comprehensive testing for dimensional accuracy, mechanical properties, and surface integrity, guaranteeing that every fastener meets or exceeds IS 1367 standards.
IS 1367 Grade 8.8 bolts demonstrate exceptional reliability in steel structures, industrial equipment, wind energy systems, and automotive applications. Wherever uncompromising fastening integrity is essential, our bolts provide the necessary performance assurance.
Yes, our Grade 8.8 bolts can be hot-dip galvanised for superior corrosion resistance, which is particularly beneficial for outdoor, marine, or corrosive industrial environments.
IS 1367 Grade 8.8 bolts maintain their mechanical properties between -20°C to 300°C, though prolonged exposure above 200°C may gradually reduce tensile strength.As technical partners, Bigboltnut offers fastener selection, application engineering, and procurement optimisation. Our team of experts provide precise and competent structural fastening solutions, volume pricing, and technical assistance.
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