Fastener Materials

Technical Office丨1/09/2018

Fasteners are manufactured in a wide range of materials from common steel to titanium, plastic and other exotic materials. Many materials are further separated into different grades to describe specific alloy mixtures, hardening processes, etc. In addition, some materials are available with a variety of coatings or platings to enhance.

Stainless steel, an alloy known for its corrosion resistance, strength, and durability. Stainless steel is one of the soft steels due to the low carbon content, therefore most stainless steel bolts are cold-formed and not heat treated. Stainless steel fasteners are typically in a clean silver color, which also makes them common in finishing and decorative applications. Stainless Steel should never be used with aluminum, galvanic corrosion is likely to occur. Here are the main types of stainless steels used for fasteners:

● 18-8 Stainless Steel: 18-8 stainless steel is a type of steel with 18% Chrome, 8% Nickel. This series may also be known as austenite steel or 304 grade steel. This cost effective version is a great choice for commercial food processing applications, refrigerators, dishwashers, as it offers good resistance to corrosion. The 304 grade is a general grade, but two other sub grades are available. These include the 304L, which is low carbon grade and can handle somewhat high temperatures, and the 304H, which is high carbon grade and offers extreme high temperature tolerance.

● 316 Stainless Steel: The chemical composition of 316 stainless steel is somewhat different in comparison to the 18-8. SS 316 contains 16% chromium and 10% nickel as well as minute amounts of other elements. SS 316 has various versions as well, such as 316L, which is a low carbon grade. There is also 316F free machining grade and 316N, which is high nitrogen grade. All are suitable for marine environments or any areas that contain high salinity.

● 410 Stainless Steel: 410 stainless steel contains a minimum of 11.5% chromium which is just sufficient enough to demonstrate corrosion resistance properties in mild atmospheres, steam, and many mild chemical environments. It is a general purpose grade that is often supplied in the hardened but still machineable condition for applications where high strength and moderate heat and corrosion resistance are required.

Carbon steel is a type of steel that contains carbon as the main alloying element, with other elements present in smaller amounts. This metal is commonly used in the manufacturing of many products and structures due to its strength, cost-effectiveness, versatility, heat treatability, availability, and ease of fabrication. Carbon steel can be further classified into various grades based on its chemical composition and mechanical properties, such as low carbon steel (mild steel), medium carbon steel, high carbon steel and ultra high carbon steel. Each grade has its own specific uses and applications, depending on the desired properties of the final product. Different fasteners grades depends on the use of different carbon steel, through heat treatment process.

● Low Carbon Steel: Low-carbon steel, also known as mild steel, has a comparatively low radio of carbon to iron compared to other steel types. Typically, its carbon content is within the range of 0.05% and 0.32% by weight. This gives low-carbon steel low strength while making it more malleable and ductile compared to high-carbon steel. Low carbon steels used in bolts manufacturing in include various grades such as AISI 1006, 1008, 1010, SAE J429 Grades 1 and 2, and European equivalents like C4C, C7C, C10C, and EN 1.0038. These steels are chosen for their good formability, ductility, weldability, and adequate strength for non-critical applications.

● Medium Carbon Steel: Contains 0.3% to 0.6% carbon content, making it stronger and harder than low-carbon steel but also more brittle. Medium carbon steels used in bolt manufacturing include various grades such as AISI 1030, 1040, 1045, SAE J429 Grade 5 and 8, and their European equivalents like C35E, C40E, C45E, and EN 1.0503. These steels offer enhanced strength and durability, making them suitable for a wide range of demanding fastener applications.

● High Carbon Steel: High carbon steel contains 0.6% to 1.5% carbon content and is known for its high strength and hardness. High carbon steels used in bolt manufacturing include grades such as AISI 1050, 1060, 1080, SAE J429 Grade 8, and their European equivalents like C55E, C60E, C70E, and EN 1.1274. These steels offer superior strength, hardness, and wear resistance, making them suitable for high-stress and high-wear applications in various industries.

Stainless Steel

Carbon Steel

Aluminum

Aluminium is a silvery-white, lightweight metal. It is soft and malleable. Aluminum is used in fastener manufacturing due to its nature, excellent corrosion resistance, good mechanical properties, and ease of fabrication. Its high strength-to-weight ratio, combined with superior thermal and electrical conductivity, makes it ideal for aerospace, automotive, marine, and electronic applications. Additionally, aluminum is non-magnetic, aesthetically appealing, recyclable, and cost-effective compared to other high-performance materials. These properties ensure aluminum fasteners are versatile, durable, and suitable for various demanding environments and applications. Aluminum alloys commonly used in fastener manufacturing include 2024, 6061, 7075, 5052, 6063, and 1100.

Brass/Bronze

Brass is used in fastener manufacturing due to its excellent corrosion resistance, which makes it ideal for environments exposed to moisture and chemicals. Its superior machinability, especially in alloys containing lead, allows for the precise and efficient production of fasteners. Brass also offers a combination of strength and ductility, ensuring durable and reliable fasteners. Additionally, its aesthetic appeal, with a natural luster that can be polished, makes it suitable for decorative applications. Brass’s good electrical conductivity further extends its use to electrical and electronic applications, making it a versatile and widely preferred material for fasteners. Brass alloys such as C360, C385, C377, C464, and C482 are commonly used in fastener manufacturing.

Plastic

Plastic fasteners are the ideal solution for fastening applications where the use of metals may cause corrosion or electrical problems. Plastic fasteners are also cost-effective, easy to produce, and can be manufactured in a variety of shapes and colors. They provide good resistance to chemicals and moisture, making them suitable for environments with exposure to these elements. Additionally, plastic fasteners are non-magnetic and have a lower risk of causing damage to delicate materials, making them suitable for use in electronics, consumer goods, and various industrial applications.

Titanium

Titanium is used in fastener manufacturing for its exceptional strength-to-weight ratio, providing high strength while remaining lightweight, which is crucial for aerospace, automotive, and high-performance applications. It offers excellent corrosion resistance, making it ideal for harsh environments, including marine and chemical industries. Titanium also has high temperature stability, maintaining its properties at extreme temperatures, and is biocompatible, making it suitable for medical implants and devices. Despite being more expensive, its durability, reliability, and specialized properties justify its use in critical and demanding applications.