You are here: Home » News » industry blog » What is a bi-metal device?

What is a bi-metal device?

Publish Time: 2025-09-19     Origin: Site


You encounter bi-metal screws in many advanced engineering projects. A bi-metal screw combines two different metals to deliver superior performance. The head and body use stainless steel for corrosion resistance, while the drill point uses hardened alloy steel for efficient drilling into tough surfaces.

The use of two metals brings several benefits:

Benefit

Description

Improved Mechanical Properties

Enhanced durability and resistance to fatigue.

Low Resistance

Efficient energy transfer for high-current tasks.

Thermal Stability

Withstands high temperatures without deforming.

Corrosion Resistance

Reliable performance in harsh environments.

Cost-effectiveness

Efficient and budget-friendly for manufacturers.

These screws matter because they offer strength, reliability, and efficiency in modern construction and industrial settings.

Key Takeaways

  • Bi-metal screws combine stainless steel and alloy steel for strength and corrosion resistance.

  • The self-drilling tip allows quick installation without pre-drilling, saving time on projects.

  • These screws resist rust and wear, making them ideal for outdoor and industrial use.

  • Bi-metal screws last longer than traditional screws, reducing maintenance and replacement costs.

  • Choose the right bi-metal screw based on your project's environment and material needs.

Bi-Metal Screw Basics

What Is a Bi-Metal Screw

You see bi-metal screws in many industries because they solve problems that single-metal screws cannot. A bi-metal screw uses two different metals in its construction. This design gives you the best qualities of each metal. The head and shank often use stainless steel, which resists rust and corrosion. The drill point uses alloy steel, which is much harder and can penetrate tough materials.

When you use a bi-metal screw, you get a fastener that works well in harsh environments. You can install it in steel, aluminum, or other metals without worrying about rust or wear. The combination of metals makes the bi-metal screw strong and reliable. You do not need to pre-drill holes because the alloy steel tip can cut through surfaces quickly.

Tip: If you need a screw for outdoor projects or industrial settings, choose a bi-metal screw for better durability and performance.

Materials Used in Bi-Metal Screws

Manufacturers select metals for bi-metal screws based on the job you need to do. The most common combination is stainless steel and alloy steel. Stainless steel gives you excellent resistance to corrosion. Alloy steel adds strength and helps the screw drill into hard surfaces.

Here is a simple breakdown of the materials:

Metal Type

Role in Bi-Metal Screw

Benefit

Stainless Steel

Head and shank

Corrosion resistance

Alloy Steel

Drill point

Strength and penetration

You might wonder how manufacturers make these screws. The process involves several steps to ensure quality and performance:

  1. Manufacturers select high-quality alloy steel and inspect it. They cut the steel into billets.

  2. Workers shape the billets using forging or casting. They machine the parts for precise dimensions.

  3. The screws go through heat treatment, such as vacuum quenching and tempering. This step increases hardness and toughness.

  4. Surface treatments like nitriding and chromium plating improve wear and corrosion resistance.

  5. Each screw passes a final inspection before packaging.

You benefit from this careful process because each bi-metal screw meets strict standards. The result is a fastener that lasts longer and performs better than ordinary screws.

How Bi-Metal Screws Work

Self-Drilling Function

You rely on bi-metal screws when you need a fastener that can cut through tough materials without extra tools. The self-drilling function sets bi-metal screws apart from standard screws. The hardened drill point acts like a drill bit. You can drive the screw directly into metal surfaces, including stainless steel, without pre-drilling. This feature saves you time and effort on the job site.

The drill point penetrates up to two sheets of stainless steel, each 1mm thick. You get a total drilling capacity of 2mm. This capability means you can use bi-metal screws in many applications, from construction to industrial assembly. The combination of a stainless steel body and an alloy steel tip gives you both corrosion resistance and strength. You achieve reliable performance even in demanding environments.

Tip: If you want to speed up installation and reduce labor costs, choose bi-metal screws for their self-drilling ability.

Corrosion Resistance

You face many challenges when working in harsh environments. Corrosion can weaken ordinary screws and shorten their lifespan. Bi-metal screws solve this problem with a stainless steel outer layer. You get high resistance to rust, salt spray, and acid rain. The bi-metal design ensures your fastener lasts longer and maintains its strength.

Here is a table that shows how bi-metal screws perform in corrosive conditions:

Feature

Specification

Salt spray resistance

1500h

Acid rain cycles

25 cycles

Service life in normal conditions

50 years

You see that bi-metal screws offer impressive durability. You can use them in outdoor applications, coastal areas, and industrial settings. The bi-metal construction protects the screw from environmental damage and keeps your projects secure.

When you compare bi-metal screws to stainless steel screws, you notice some important differences:

Feature

Bi-metal Screws

Stainless Steel Screws

Corrosion Resistance

High, due to stainless steel outer layer

Very high, but may gall under pressure

Strength

Superior tensile strength from carbon steel core

Generally lower than bi-metal screws

Cost Efficiency

More economical due to combination of materials

Typically more expensive

Versatility

Suitable for various applications

Limited to specific uses

You benefit from the bi-metal design because it combines the best properties of both metals. You get a screw that resists corrosion, delivers high strength, and fits a wide range of applications. The bi-metal screw stands out as a reliable choice for anyone who values long-lasting performance.

Features of Bi-Metal Screws

Strength and Durability

When you choose a bi-metal screw, you get a fastener built for strength and long life. The key features of bi-metal screws include a unique combination of metals. Stainless steel gives you excellent corrosion resistance, while carbon steel or alloy steel adds impressive strength. This blend helps the screw handle heavy loads and tough environments.

You can see the difference in tensile strength when you compare bi-metal screws to traditional screws. The table below shows how much force each gauge can handle:

Gauge

#6

#8

#10

#12

#14

Value (Kgf)

689

986

1269

1663

2286

You notice that bi-metal screws offer much higher strength than standard options. This makes them ideal for applications where you need reliable fastening under stress. You also benefit from their ability to resist bending and fatigue. The bi-metal design ensures the screw keeps its shape and holds tight, even in demanding conditions.

  • Bi-metal screws combine stainless steel's corrosion resistance with carbon steel's strength.

  • They withstand bending and fatigue, which is crucial for high-stress applications.

  • SS/CS bimetal composite bolts meet high fatigue strength requirements, making them suitable for demanding environments.

Performance Benefits

You gain several performance advantages when you use bi-metal screws. One of the biggest benefits is faster installation. The self-drilling tip lets you drive the screw quickly, saving you time on every project. The table below compares installation speed:

Feature

Bi-Metal Screws

Traditional Screws

Driver Speed (R.P.M.)

Up to 1800

800

Installation Time (seconds)

3.2

8.5

Speed Comparison

>2 times faster

N/A

You can finish jobs in less time and with less effort. The bi-metal screw also lasts longer, which means you replace it less often. The table below shows the difference in lifespan:

Screw Type

Lifespan

Replacement Frequency

Traditional Screws

3-5 years

Every 3-5 years

Bi-metal Screws

8-10 years

Every 8-10 years

You save money on maintenance and reduce downtime. The bi-metal construction, along with surface treatments like hot-dip galvanizing, boosts corrosion resistance. This makes the screw a smart choice for harsh environments and outdoor applications. You get a fastener that delivers strong performance, resists rust, and stands up to tough jobs.

Applications of Bi-Metal Screws

Bi-metal screws play a vital role in many industries. You see these fasteners in places where strength, corrosion resistance, and reliability matter most. Their unique construction allows you to use them in a wide range of common applications.

Industrial Uses

You often find bi-metal fasteners in factories and heavy machinery. These screws meet strict safety standards, making them a trusted choice for demanding jobs. The table below highlights key features that make bi-metal screws suitable for industrial use:

Feature

Description

Material

300 (18-8) stainless steel head and shank

Drill Point

Fused and hardened steel drill point

Coating

Silver-colored Stalgard® GB coating

Corrosion Resistance

Virtually immune to delayed embrittlement failures

Application

Structural steel and aluminum up to ½” thick

You can use bi-metal screws for assembling structural steel frames, joining aluminum panels, and securing equipment. Their performance remains stable even in harsh environments. Bi-metal roofing screws and bi-metal wood-to-metal screws are common in industrial settings, providing secure connections for roofs, walls, and support structures.

Tip: Choose bi-metal screws when you need a fastener that resists corrosion and handles heavy loads.

Construction and Automotive

In construction, you rely on bi-metal screws for their durability and versatility. These fasteners work well for metal-to-metal, metal-to-wood, and even metal-to-other material connections. The table below shows why builders prefer bi-metal screws:

Advantage

Description

Durability

Long-lasting, reliable connections in harsh environments

Versatility

Suitable for many material combinations

High Strength

Exceptional holding power and corrosion resistance

Efficiency

Faster installation with enhanced drilling capacity

You benefit from features like self-healing ability, which helps the screw maintain corrosion resistance after minor damage. The thermal expansion coefficient matches different materials, so you get a stable fit. Good electrical conductivity makes these screws reliable for grounding tasks. Anti-vibration properties prevent loosening under dynamic loads.

In automotive manufacturing, you see bi-metal screws used in seat rails, exhaust pipe fastenings, and battery pack frames. Their resistance to electrolyte corrosion makes them ideal for new energy vehicles. You get strong, reliable connections that withstand high temperatures, vibrations, and rust.

Note: Bi-metal screws outperform traditional screws in both construction and automotive applications, giving you better results and longer-lasting performance.

Choosing the Right Bi-Metal Screw

Types of Bi-Metal Screws

You find several types of bi-metal fasteners designed for different tasks. Bi-metal screws feature helical threads that grip building surfaces tightly, giving you a stronger hold than nails. You use these screws in construction, framing, roofing, and decking. The combination of stainless steel and hardened carbon steel provides high strength and corrosion resistance. Bi-metal self-drilling screws work well for securing metal to wood, metal, or composite panels. You rely on these fasteners for structural applications where reliable performance matters most.

Type

Common Use

Key Feature

Self-Drilling Bi-Metal

Metal-to-metal, roofing

Drills without pre-holes

Wood-to-Metal Bi-Metal

Decking, framing

Strong grip in wood

Composite Panel Bi-Metal

Cladding, facades

Versatile compatibility

Tip: Choose bi-metal construction for projects that need both strength and resistance to harsh environments.

Selection Tips

When choosing the right bi-metal screw, you need to consider several factors. The environment plays a big role. In aggressive settings, select bi-metal fasteners made with Bi-Flex 300 Series Stainless Steel for maximum corrosion resistance. Look at the type of corrosion you expect, the mechanical strength needed, and the durability required.

  • Match the fastener material to the substrate to avoid dissimilar metal corrosion.

  • If matching is not possible, make sure the fastener offers equivalent corrosion resistance.

  • Avoid using galvanized steel fasteners with aluminum cladding systems.

  • Select coatings that protect against salt spray, acid rain, or ACQ-treated wood.

You should also avoid common mistakes:

  1. Use the correct screw length for your material.

  2. Check the thickness of the substrate before installation.

  3. Pick screws designed for outdoor use if exposed to weather.

  4. Align screws properly to prevent weak joints.

  5. Countersink screws to avoid splitting materials.

  6. Do not over-tighten, which can damage threads.

  7. Use quality tools for installation.

  8. Pre-drill holes if needed for a clean fit.

  9. Always follow safety measures.

You get reliable performance when you select bi-metal screws that match your project’s needs. The right choice ensures long-lasting results and reduces maintenance.

You gain many advantages when you choose a bi-metal screw for your project.

  • The hardened tip drills through tough materials, while the stainless steel body resists corrosion and stays ductile.

  • You find longer screws for thicker insulation, making them perfect for construction.

  • The bi-metal design gives you reliable performance, lower maintenance, and secure fastening in harsh conditions.

Future Trend

Description

Advanced Materials

Hybrid alloys boost durability and strength.

Automation

Smart systems and AI improve screw quality.

You should select the right bi-metal screw to ensure your project lasts longer and performs better.

FAQ

What makes bi-metal screws different from regular screws?

You get a unique combination of strength and corrosion resistance with bi-metal screws. Manufacturers use two metals to create a fastener that performs better in harsh environments. You can rely on bi-metal screws for tough jobs where regular screws might fail.

Where should you use bi-metal screws?

You can use bi-metal screws in construction, automotive, and industrial projects. These screws work well for metal-to-metal, metal-to-wood, and composite panel connections. You see bi-metal screws in roofing, framing, and heavy machinery because they last longer and resist rust.

How do you install bi-metal screws?

You install bi-metal screws with a standard power drill. The self-drilling tip lets you drive the screw directly into metal or wood without pre-drilling. You save time and effort. Always check the substrate thickness and use the correct screw length for your project.

Do bi-metal screws resist corrosion?

You get excellent corrosion resistance with bi-metal screws. The stainless steel body protects against rust, salt spray, and acid rain. You can use bi-metal screws outdoors, in coastal areas, or in places with harsh weather. These screws keep your projects secure for years.

Can you use bi-metal screws for electrical applications?

You can use bi-metal screws for electrical grounding and connections. The design offers good conductivity and resists corrosion from electrolytes. You see bi-metal screws in battery pack frames and automotive electrical systems. Always match the screw material to the substrate for best results.

ABOUT US

We have a complete range of processing equipment and production lines, adopts Taiwan manufacture technology and experience.
 

CONTACT US

Email: emily@beyondfastener.com
Tel: +86-15307690280
WhatsApp: +86-15307690280
Wechat: +86-15307690280
Skype: xuanyuan0111
Copyright ©2022 Beyond Industry Groups Co., Ltd. SitemapPrivacy Policy | Supported By Leadong     粤ICP备2023015836号-1