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M18 x 138mm 304 Stainless Hex Cap Screw

Expert Overview

This M18 x 138mm Hex Head Cap Screw is precision-manufactured from premium 304 stainless steel. Offering superior corrosion resistance and mechanical strength, it's ideal for critical fastening applications.

StandardISO 9001
Material304 Stainless Steel
FinishPassivated
GradeN/A
SizeM18
Length138mm
Head Width28mm

Detailed Engineering Specifications

Engineered for reliability and performance, this M18 Hex Head Cap Screw features a nominal diameter of 18mm and a substantial length of 138mm, ensuring deep thread engagement. The robust 28mm hexagonal head provides ample surface area for torque application, facilitating secure fastening. Constructed from 304 stainless steel, it exhibits excellent resistance to oxidation and corrosion, making it suitable for marine, chemical processing, and outdoor environments where exposure to moisture and aggressive substances is a concern. Its high tensile strength ensures dependable load-bearing capacity in demanding structural and mechanical assemblies.

🧊 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. Clean mating surfaces and threads of both the screw and the receiving hole. 2. Apply a suitable lubricant or anti-seize compound if recommended for the application, avoiding over-application. 3. Thread the cap screw into the receiving component by hand to ensure proper alignment and prevent cross-threading. 4. Tighten the cap screw to the specified torque using an appropriate wrench or socket on the hex head, employing a calibrated torque wrench for critical applications.

Equivalent Standards (Cross-Reference)

Standard SystemDesignation
ISO EquivalentISO 898-1 / ISO 4014
DIN EquivalentDIN 931 / DIN 933
Primary StandardISO 9001

Mechanical Properties

Tensile Strength75,000 psi (515 MPa)
Yield Strength30,000 psi (205 MPa)
Elongation in 2 in.40% min
HardnessRockwell B95 max

Chemical Composition

Carbon (C)0.08% max
Chromium (Cr)18.0 - 20.0%
Nickel (Ni)8.0 - 10.5%
Manganese (Mn)2.00% max

Temperature & Environment Rating

Min Operating Temp
-320°F (-195°C)
Max Continuous Temp
1400°F (760°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 / SaltwaterGood
Chemical / AcidicNot Recommended

Common Mistakes & How to Avoid Them

❌ Mistake✅ Correct Approach
Cross-threading due to improper alignment during initial insertion.Always start threading the screw by hand to confirm proper thread engagement before applying any torque.
Over-tightening, leading to thread stripping or material deformation.Utilize a calibrated torque wrench and adhere to the manufacturer's specified torque values for the application.
Using the wrong tool size, which can strip the hex head or lead to improper torque application.Ensure the correct size socket or wrench is used for the 28mm hex head to achieve secure fastening.

Common Applications

  • Structural steel connections
  • Machinery and equipment assembly
  • Outdoor and marine applications

⚠️ Engineering Warnings

  • Ensure the mating material can withstand the clamping force generated by this screw.
  • For critical load-bearing applications, consult engineering specifications for appropriate torque values and thread engagement.

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, 304 Stainless Steel made from?

A: This Hex Head Cap Screw, 304 Stainless Steel is manufactured from 304 Stainless Steel.

Q: What are the main applications?

A: Structural steel connections, Machinery and equipment assembly, Outdoor and marine applications.

Technical Schematic

HEX BOLT DIAGRAMSAE J429 / ASME B18.2.1HEXHEADLENGTH = 138mmAF28mm1/2"-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.