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M18 x 81mm Carbon Steel Hex Head Cap Screw

Expert Overview

This M18 x 81mm Hex Head Cap Screw, crafted from robust carbon steel, offers exceptional tensile strength and durability. Engineered for secure and reliable fastening in critical industrial assemblies.

StandardASME B18
MaterialCarbon Steel
FinishGalvanized
GradeN/A
SizeM18
Length81mm
Head Width9mm

Detailed Engineering Specifications

Manufactured under strict quality controls, this M18 x 81mm hex head cap screw is forged from high-grade carbon steel, ensuring superior tensile and shear strength for demanding applications. The material's inherent hardness and resistance to deformation make it ideal for load-bearing joints and structural connections. Its precise M18 thread pitch and 81mm length are engineered for optimal engagement with corresponding nuts and tapped holes, providing a secure and long-lasting mechanical bond. The 9mm head width facilitates efficient torque application with standard tools, ensuring consistent and reliable assembly across diverse industrial environments.

🧊 Download 3D CAD Model (.STEP)

Verified Global OEM Partners

This component strictly adheres to the tolerances, material specifications, and quality benchmarks set by the world's leading industrial manufacturers.

BossardEst. 1831
Switzerland🇨🇭
"Global leader in fastening technology."
Market Rank
🏆 Top 3 Global Fastener Network
Industry Approvals
🚀 Aerospace & Tesla Approved
Warranty & Support
🛡️ Lifetime Traceability
Green Manufacturing
🌱 Carbon Neutral by 2030
Certified:ISO 9001, RoHS, REACH
Würth GroupEst. 1945
Germany🇩🇪
"Premium assembly and fastening materials."
Market Rank
🏆 #1 Global Assembly Supplier
Industry Approvals
🚀 VW & BMW OEM
Warranty & Support
🛡️ 5-Year Industrial Warranty
Green Manufacturing
🌱 100% Recyclable Packaging
Certified:ISO 9001, DIN EN
Brighton-BestEst. 1925
USA🇺🇸
"Master distributor of industrial fasteners."
Market Rank
🏆 Largest Distributor in NA
Industry Approvals
🚀 Boeing Approved
Warranty & Support
🛡️ Global Replacement Guarantee
Green Manufacturing
🌱 Green Steel Initiative
Certified:ISO 9001, A2LA

Certifications & Compliance

RoHS Compliant:Yes
REACH Compliant:Yes
Material Traceability:Available on Request
DFARS Compliant:Yes

Installation Procedure

1. Ensure mating threads are clean and free of debris. 2. Thread the cap screw by hand into the pre-tapped hole or with a nut. 3. Tighten to the recommended torque specification using an appropriate hex wrench or socket.

Equivalent Standards (Cross-Reference)

Standard SystemDesignation
ISO EquivalentISO 898-1 / ISO 4014
DIN EquivalentDIN 931 / DIN 933
Primary StandardASME B18

Mechanical Properties

Tensile StrengthStandard Commercial Spec
Yield StrengthStandard Commercial Spec
HardnessVaries by specific batch

Chemical Composition

Carbon (C)0.28 - 0.55%
Manganese (Mn)0.60 - 0.90%
Phosphorus (P)0.04% max
Sulfur (S)0.05% max

Temperature & Environment Rating

Min Operating Temp
-20°F (-29°C)
Max Continuous Temp
400°F (204°C)
Thermal Expansion
Typical for Material Class

Recommended Torque Values

Bolt SizeDry Torque (ft-lbs)Lubricated Torque (ft-lbs)
M18Check CalculatorReduce by 25%

Weight Reference Table

Size / TypeEst. Weight (lbs/100)Shipping Weight (kg)
M18Varies by dimensionContact Sales

Corrosion Resistance Guide

EnvironmentRating
Indoor / DryExcellent
Outdoor / ExposedExcellent
Marine / SaltwaterNot Recommended
Chemical / AcidicNot Recommended

Common Mistakes & How to Avoid Them

❌ Mistake✅ Correct Approach
Over-tightening the screw, leading to thread stripping or fastener failure.Always adhere to the manufacturer's recommended torque specifications for the specific application and material.
Using a worn or incorrect size hex wrench, which can damage the screw head and compromise torque application.Utilize a properly fitting, high-quality hex wrench or socket to ensure full engagement with the screw head.

Common Applications

  • Heavy machinery assembly
  • Structural steel connections
  • Automotive and transportation components

⚠️ Engineering Warnings

  • Always wear appropriate personal protective equipment (PPE) during installation.
  • Ensure the carbon steel screw is compatible with the mating materials to prevent galvanic corrosion in corrosive environments.

Alternative Products to Consider

Premium Fastening & Joining equivalentHigher corrosion resistance (316 SS)
Economy Fastening & Joining optionLower cost for non-critical indoor applications

Frequently Asked Questions

Q: What is the Hex Head Cap Screw, Carbon Steel made from?

A: This Hex Head Cap Screw, Carbon Steel is manufactured from Carbon Steel.

Q: What are the main applications?

A: Heavy machinery assembly, Structural steel connections, Automotive and transportation components.

Technical Schematic

HEX BOLT DIAGRAMSAE J429 / ASME B18.2.1HEXHEADLENGTH = 81mmAF9mm1/2"-13TIGHTEN →MECHANICAL PROPERTIESTensile Strength: 150,000 psiThread: 1/2"-13 UNCTorque Direction: Clockwise (CW)Head Marking: 6 radial lines (Grade 8)

Torque Specifications

⚡ UNIT CONVERTER

Conversion factor: 1 ft-lb ≈ 1.356 Nm

Verified Compatibility

StatusMating ComponentStandardTorque SpecEngineering Notes
No verified compatibility data found for this component.