M4 (4mm) Button Head Bolt Allen Socket Screws

M4 Button Head Bolt

Top quality stainless steel button head bolt supplied straight from Warrington, UK.

Apart from our extensive range of button head screws, Speciality Metals stocks a variety of both standard fasteners and specialist fasteners, including both steel and stainless steel fasteners, nuts and bolts, screws and steel washers.

We ensure that we offer a comprehensive range which meets the needs and requirements of each and every one of our customers, whether you are looking for standard fasteners or something a little more unusual.

Speciality Metals offers M4 (4mm) button head bolt Allen socket screws that are made from 304 grade stainless steel. Because they are low maintenance and have hygienic properties, they are ideal for a variety of industries, including food and medicine. They are corrosion-resistant, as well as providing a secure fit, ensuring the safety and integrity of your project. Count on Speciality Metals’ button head bolts to deliver the quality and performance you need.

We also offer washers that will compliment our range of screws and bolts perfectly. 

Key product details:

• Standard – DIN 912
• Fasteners Type – Button Head Allen Socket Bolt Screw
• Shape – Round
• Drive Style – Allen Key
• Thread Diameter – M4 (4mm)
• Screw Length – Various
• Metal – Stainless steel grade 304 (A2)

Why Choose Speciality Metals

• FREE UK delivery on all orders
• Order dispatch within 24 hours of order
• Located in Warrington, UK which is the UK home of mesh and metals
• Our experienced staff are experts in the mesh market and care personally about your customer experience

Furthermore we stock a vast range of plain wire mesh and perforated metal options that compliment our sheet metal range perfectly.

What is a Button Head Bolt Screw?

A button head screw, is a type of fastener that has a rounded or dome-shaped head. The head is typically wider than that of a standard screw, which provides a larger bearing surface and is often used for aesthetic purposes as it creates a neat and finished look. The drive type for button head screws can vary, but common ones include hex, Phillips or Torx. Button head screws are used in a variety of applications including machinery, tools and structural assemblies, and are commonly found in automotive, electronic and furniture applications. They are available in a variety of materials, sizes and thread types, including stainless steel, which is commonly used for its corrosion resistance.

Are Stainless Steel Button Head Bolts Resistant to Corrosion?

Stainless steel 304 grade is one of the most commonly used types of stainless steel and is known for its ability to resist corrosion. The 304 grade contains a significant amount of chromium (18-20%) and nickel (8-10.5%) which allows it to form a passive layer of chromium oxide on its surface that provides a degree of protection against corrosive elements. However, while 304-grade stainless steel button head bolts offer good corrosion resistance in many environments, they are not immune to corrosion. They can be susceptible to pitting and crevice corrosion in chloride environments or when exposed to high temperatures for prolonged periods. Also, in low-oxygen or high-salinity environments, even 304 stainless steel can corrode because the protective oxide layer may not be able to form or maintain itself. Additionally, stress from tension or vibration can lead to stress corrosion cracking in specific conditions. Therefore, while 304-grade stainless steel button head bolts offer good corrosion resistance in many applications, they may not be suitable for all environments, particularly those with high chloride concentrations, high temperatures or low oxygen availability. It’s important to carefully consider the specific application and environmental conditions when selecting the material for your bolts.

Can Stainless Steel Button Head Bolts be Used in Marine Applications?

Stainless steel button head bolts can be used in marine applications, but it is important to select the appropriate grade of stainless steel. The marine environment is particularly challenging due to the presence of saltwater, which is highly corrosive.

Grade 316 stainless steel is often recommended for marine applications due to its higher resistance to chloride corrosion compared to grade 304 stainless steel. Grade 316 contains molybdenum, which enhances its resistance to pitting and crevice corrosion in chloride environments.

However, even 316-grade stainless steel is not immune to all forms of corrosion in the marine environment, particularly in areas with high salinity, low oxygen or high temperatures. For critical applications or harsh environments, it may be necessary to consider even more corrosion-resistant materials, such as duplex or super duplex stainless steels or to apply additional protective coatings.

It is also important to consider other factors, such as mechanical stress and galvanic corrosion, when selecting fasteners for marine applications.

What are the Common Applications of Stainless Steel Button Head Bolts?

1. Architectural and Structural Applications: Used in buildings, bridges and other structures where both aesthetic appeal and resistance to the elements are important.

2. Automotive Applications: Used in vehicles, particularly in parts exposed to the elements or where a smooth, low-profile head is desired.

3. Equipment and Machinery: Used in the assembly of equipment and machinery, particularly in the food and beverage, pharmaceutical and chemical industries where corrosion resistance is important.

4. Electronics: Used in the assembly of electronic devices and equipment where a smooth, low-profile head is desired.

5. Outdoor Applications: Used in outdoor structures, such as decks, fences and playground equipment, where resistance to the elements is important.

6. Aerospace: Used in the assembly of aircraft and other aerospace equipment where strength, weight and resistance to the elements are important.

What types of driver are used for stainless steel button head screws?

Stainless steel button head screws commonly use an Allen (hexagonal) wrench for installation and removal. This is because the hex socket drive allows for higher torque application compared to other drive types. However, stainless steel button head screws can also be found with other drive types such as Phillips, Torx (star) or slotted, depending on the manufacturer’s design. The choice of drive type will depend on the application and the tools available. Hex and Torx drives are generally preferred for applications requiring higher torque.

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