Engineered for robust performance, this M20 x 81mm Hex Head Cap Screw is manufactured from high-grade carbon steel. It offers superior tensile strength and durability, making it ideal for critical structural and mechanical assemblies.
| Standard | ASME B18 |
| Material | Carbon Steel |
| Finish | Plain |
| Grade | N/A |
| Size | M20 |
| Length | 81mm |
| Head Width | 21mm |
Trusted by engineers across multiple sectors, this M20 x 81mm Hex Head Cap Screw is forged from premium carbon steel, offering excellent tensile strength and shear resistance. The nominal diameter is M20, with a specified length of 81mm and a nominal head width of 21mm. Its robust construction ensures reliable load-bearing capacity in applications demanding high torque and resistance to vibration. This fastener is suitable for use in environments where moderate corrosion resistance is acceptable and superior mechanical performance is paramount, such as in heavy machinery, automotive chassis, and structural steel fabrication.
This component strictly adheres to the tolerances, material specifications, and quality benchmarks set by the world's leading industrial manufacturers.
1. Ensure threads on both the screw and the mating component are clean and free of debris. 2. Apply appropriate lubricant or anti-seize compound to the threads if recommended for the application. 3. Insert the screw into the designated hole and begin threading by hand to prevent cross-threading. 4. Using a properly sized wrench or socket, tighten the screw to the specified torque value, ensuring even pressure and avoiding over-tightening.
| Standard System | Designation |
|---|---|
| ISO Equivalent | ISO 898-1 / ISO 4014 |
| DIN Equivalent | DIN 931 / DIN 933 |
| Primary Standard | ASME B18 |
| Tensile Strength | Standard Commercial Spec |
| Yield Strength | Standard Commercial Spec |
| Hardness | Varies by specific batch |
| Carbon (C) | 0.28 - 0.55% |
| Manganese (Mn) | 0.60 - 0.90% |
| Phosphorus (P) | 0.04% max |
| Sulfur (S) | 0.05% max |
| Bolt Size | Dry Torque (ft-lbs) | Lubricated Torque (ft-lbs) |
|---|---|---|
| M20 | Check Calculator | Reduce by 25% |
| Size / Type | Est. Weight (lbs/100) | Shipping Weight (kg) |
|---|---|---|
| M20 | Varies by dimension | Contact Sales |
| Environment | Rating |
|---|---|
| Indoor / Dry | Excellent |
| Outdoor / Exposed | Moderate |
| Marine / Saltwater | Not Recommended |
| Chemical / Acidic | Not Recommended |
| ❌ Mistake | ✅ Correct Approach |
|---|---|
| Using an incorrect size wrench, leading to stripped hex heads. | Always use a wrench or socket that precisely fits the 21mm head width to ensure proper torque application and prevent damage. |
| Cross-threading the screw due to improper initial engagement. | Start threading the screw by hand for at least two full turns to confirm correct thread alignment before applying mechanical force. |
| Over-tightening the screw, which can lead to thread stripping or fastener failure. | Consult engineering drawings or torque charts for the specific application and use a calibrated torque wrench to achieve the recommended tightening specification. |
A: This Hex Head Cap Screw, Carbon Steel is manufactured from Carbon Steel.
A: Heavy Machinery Assembly, Automotive Chassis Construction, Structural Steel Fabrication.
Conversion factor: 1 ft-lb ≈ 1.356 Nm
| Status | Mating Component | Standard | Torque Spec | Engineering Notes |
|---|---|---|---|---|
| No verified compatibility data found for this component. | ||||