Illustrative drawing. Actual product is confirmed to your specification at quotation.
Bolts
High-Tensile Bolts
High-tensile bolts are heat-treated to higher strength classes, marked on the head. Use matching nut classes. Class 12.9 and 10.9 fasteners can be susceptible to hydrogen embrittlement after electro-plating, so check the coating process.
- Class marked on the head
- Match with class 8, 10 or 12 nuts
- Check coating for hydrogen embrittlement risk
Specifications
- Material
- Carbon steelAlloy steelStainless steel A2 (AISI 304)Stainless steel A4 (AISI 316)
- Grade / property class
- 8.810.912.9
- Thread
- Metric coarse (ISO 261)Metric fine pitchUNC / UNF (imperial)
- Finish / coating
- PlainBlack oxideZinc plated (clear / yellow)Hot-dip galvanised
- Size range
- Up to M6M8–M12M14–M24M27–M48
- Standards
- ISO 898-1IS 1367DIN 931 / 933 (dimensions)ISO 4014 / 4017
Exact dimensions, lengths and availability are confirmed at quotation.
Applications
- Heavy machinery and presses
- Engines, gearboxes and drive trains
- Construction equipment
- Wind and power equipment
- Critical structural joints
Technical reference
Hex head bolt dimensions (ISO 4014 / ISO 4017)
| Thread | Pitch (mm) | Width across flats s (mm) | Head height k (mm) |
|---|---|---|---|
| M5 | 0.8 | 8 | 3.5 |
| M6 | 1.0 | 10 | 4.0 |
| M8 | 1.25 | 13 | 5.3 |
| M10 | 1.5 | 16 | 6.4 |
| M12 | 1.75 | 18 | 7.5 |
| M16 | 2.0 | 24 | 10.0 |
| M20 | 2.5 | 30 | 12.5 |
| M24 | 3.0 | 36 | 15.0 |
| M30 | 3.5 | 46 | 18.7 |
| M36 | 4.0 | 55 | 22.5 |
Nominal head height k and width across flats s, in mm, for standard hex head bolts. Confirm against your drawing.
Property classes of bolts and screws (ISO 898-1)
| Property class | Tensile strength Rm min (MPa) | Yield strength Re min (MPa) |
|---|---|---|
| 4.6 | 400 | 240 |
| 5.6 | 500 | 300 |
| 8.8 (up to M16) | 800 | 640 |
| 10.9 | 1040 | 940 |
| 12.9 | 1220 | 1100 |
Minimum tensile strength Rm and minimum yield / proof strength Re (or Rp0.2) in MPa. Class 8.8 shows the value for sizes up to M16; larger sizes have slightly higher values.
Related and complementary fasteners
Request a quote for High-Tensile Bolts
Give us the size, grade, finish and quantity. We reply within one business day.
Common questions
- Which sizes and grades of high-tensile bolts do you supply?
- We supply high-tensile bolts in Up to M6, M8–M12, M14–M24, M27–M48 size bands and grades/classes including 8.8, 10.9, 12.9. Exact availability, dimensions and lead time are confirmed at quotation.
- Which standards do high-tensile bolts follow?
- Common standards are ISO 898-1, IS 1367, DIN 931 / 933 (dimensions), ISO 4014 / 4017. Tell us the standard you need and we will quote to it.
- Can you supply in bulk or with test certificates?
- Yes. We quote for loose lots and scheduled bulk supply across India, and can share manufacturer test certificates where available. Confirm the requirement when you request a quote.
Need a quote on bulk or custom industrial supply?
Share your specifications and quantities — our technical team will respond with pricing and lead time within one business day.