Not All Screws Are the Same: How to Choose the Right Material—From Carbon Steel to Inconel 718
- 翰君 陳
- 22 hours ago
- 3 min read
When people choose screws, they usually look at size, thread pitch, and head type first.But in real applications, what truly determines whether a screw will fail is often the material.
Rust, stripped threads, breakage, deformation, or loosening over time—many of these issues are not caused by poor machining, but by choosing the wrong material from the start.
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1. Why Does Screw Material Matter So Much?
In use, a screw typically faces multiple factors at the same time:
Tightening torque during installation
Long-term tensile or shear loads
Temperature changes
Moisture, chemicals, and outdoor exposure
Repeated assembly/disassembly and fatigue
Material selection decides whether the screw can survive these conditions.
If the size is wrong, you can’t assemble it right away.If the material is wrong, problems often appear after some time, and once they happen, they’re usually hard to fix.
--- 2. A Clear Overview of Common Screw Materials
Below are the most common screw materials in real-world use—and the ones most often misunderstood or mixed up.
Screw Material Comparison
Material (CN/EN) | One-line Summary | Best For |
Carbon Steel | Most common, cost-effective | Furniture, general hardware, non-corrosive environments |
Stainless Steel 304 / A2 | Good corrosion resistance | Outdoor use, food equipment, general electronics |
Stainless Steel 316 / A4 | Excellent against seawater & chemicals | Coastal, chemical, medical equipment |
Alloy Steel (Class 8.8 / 10.9 / 12.9) | High strength | Automotive, machinery, structural parts |
Brass | Corrosion-resistant, conductive | Electronics, plumbing/electrical, decorative use |
Aluminum | Lightweight, won’t rust | Lightweight structures, heat dissipation modules |
Titanium | Light, strong, highly corrosion-resistant | Aerospace, medical, high-end equipment |
Nylon / POM | Electrical insulation, non-conductive | Electronics, appliances, lab equipment |
PEEK | High temperature & chemical resistance | Semiconductor, vacuum, medical |
Inconel 718 (Nickel-based superalloy) | Stable under high heat & pressure | Aerospace, energy, extreme environments |
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3. Why Stainless Steel Is Not a “Universal Solution”
Many people think: “If I’m worried about rust, I’ll just use stainless steel.”
That’s only half true.
Stainless steel is great for corrosion resistance, but it has clear limitations:
Strength is often lower than high-strength alloy steel
Higher risk of galling (especially stainless-on-stainless)
Performance can be limited under high temperature or high stress
That’s why in automotive, structural, and heavy-duty equipment, it’s common to choose high-strength alloy steel with proper surface treatment, rather than stainless steel.
--- 4. When Does Material Become the Main Cause of Failure?
Here are the most common scenarios seen in machining and maintenance:
Outdoor equipment using carbon steel → rusts and seizes over time
High-temperature environments using general stainless → insufficient strength
High-torque fastening using 304 → stripped threads
Chemical environments with wrong material → corrosion or fracture
These issues usually don’t happen immediately—they show up after the equipment has been running for a while.
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5. What Level of Material Is Inconel 718?
Inconel 718 is a nickel-based high-temperature superalloy designed for one purpose:
To stay stable under high heat, high pressure, and long-term operation.
Key characteristics:
Retains strength at high temperatures
Excellent fatigue and creep resistance
Strong oxidation and corrosion resistance
Maintains dimensional stability in extreme conditions
Typical applications:
Aerospace engines
Energy and power-generation equipment
High-temperature process equipment
Specialized industrial use
This material isn’t chosen because it’s “better in general,” but because other materials fail in those conditions.
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6. How to Choose the Right Material—Without Overkill or Under-spec
A practical rule of thumb:
General fastening → carbon steel or stainless steel
High strength required → alloy steel
Corrosive environments → 304 / 316 or special materials
High heat / extreme conditions → Inconel 718, PEEK, and other advanced materials
The goal is not “the most premium material,” but the one that matches the real conditions—without unnecessary cost.
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7. Why Choose Sheng Fong Precision?
In practice, the question isn’t “Do you have screws?”It’s “Which material is right for this specific condition?”
Sheng Fong Precision can help you:
Evaluate the real environment and prevent wrong material selection
Provide multiple material options and matching specifications
Support selection for advanced materials and special requirements
Support maintenance, replacements, small quantities, and spare parts planning
📩 LINE: @s9000
Share your application and specs—we’ll help you choose the right material, not just the expensive one.
🛒 Full specification list: https://lihi3.me/f9QxW Screw selection guide: https://lihi3.me/j8UV9
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