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M21x56mm 316 Stainless Steel Hex Head Cap Screw

Expert Overview

Engineered for superior performance, this M21x56mm hex head cap screw is crafted from high-grade 316 stainless steel. Offering exceptional corrosion resistance and mechanical strength, it ensures reliable fastening in challenging environments.

StandardDIN 933
Material316 Stainless Steel
FinishBlack Oxide
GradeN/A
SizeM21
Length56mm
Head Width18mm

Detailed Engineering Specifications

Specified by design engineers worldwide, this M21x56mm hex head cap screw features an M21 nominal thread size and a length of 56mm. The head is designed with a 18mm width for compatibility with standard tooling. Manufactured from 316 stainless steel, it exhibits superior resistance to pitting and crevice corrosion, particularly in chloride-rich environments. This makes it ideal for marine, chemical processing, and food & beverage applications where material integrity is paramount.

🧊 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 the mating threads are clean and free from debris. 2. Engage the cap screw by hand for the first few threads to prevent cross-threading. 3. Tighten using a calibrated torque wrench to the specified torque value for the application, ensuring even pressure distribution.

Equivalent Standards (Cross-Reference)

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

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)16.0 - 18.0%
Nickel (Ni)10.0 - 14.0%
Molybdenum (Mo)2.0 - 3.0%

Temperature & Environment Rating

Min Operating Temp
-320°F (-195°C)
Max Continuous Temp
1500°F (815°C)
Thermal Expansion
Typical for Material Class

Recommended Torque Values

Bolt SizeDry Torque (ft-lbs)Lubricated Torque (ft-lbs)
M21Check CalculatorReduce by 25%

Weight Reference Table

Size / TypeEst. Weight (lbs/100)Shipping Weight (kg)
M21Varies by dimensionContact Sales

Corrosion Resistance Guide

EnvironmentRating
Indoor / DryExcellent
Outdoor / ExposedExcellent
Marine / SaltwaterExcellent
Chemical / AcidicGood

Common Mistakes & How to Avoid Them

❌ Mistake✅ Correct Approach
Using the wrong size wrench, leading to head stripping.Always use the correct size hex wrench or socket for the 18mm head width.
Over-tightening, which can damage the threads or the components being joined.Adhere to the manufacturer's recommended torque specifications for the application.

Common Applications

  • Marine hardware and shipbuilding
  • Chemical processing equipment
  • Food and beverage processing machinery

⚠️ Engineering Warnings

  • While 316 stainless steel offers excellent corrosion resistance, it can still be susceptible to certain aggressive chemicals at high concentrations and temperatures. Verify compatibility.
  • Ensure proper thread engagement and torque to prevent fastener failure and maintain structural integrity.

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, 316 Stainless Steel made from?

A: This Hex Head Cap Screw, 316 Stainless Steel is manufactured from 316 Stainless Steel.

Q: What are the main applications?

A: Marine hardware and shipbuilding, Chemical processing equipment, Food and beverage processing machinery.

Technical Schematic

HEX BOLT DIAGRAMSAE J429 / ASME B18.2.1HEXHEADLENGTH = 56mmAF18mm1/2"-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.