For anyone working with hardware, the age-old problem of knowing whether the screws you are using are genuinely stainless steel can be a head-scratcher. Stainless steel screws are prized for their corrosion resistance, making them essential for applications exposed to the elements, like decking, outdoor furniture, and marine environments. However, not all screws labeled as stainless steel are the real deal. This uncertainty can lead to issues from aesthetics to safety and structural integrity.

Here we will clear the confusion around what makes a screw stainless steel, and methods to ensure the screws you're using are truly stainless steel.

Understanding Stainless Steel Grades and Materials

Stainless steel screws come in a variety of grades, with three main grades commonly used in applications. Understanding these grades is essential to select the right one for the task.

302 Grade Stainless Steel

Considered low-quality stainless steel, 302-grade screws offer minimum corrosion resistance. While less prone to rust than regular steel, they are not recommended for applications that demand high anti-corrosion properties.

305 Grade Stainless Steel

A step up from 302, the 305 grade is the industry standard for general-use stainless steel screws, especially for outdoor use in non-marine environments. Offering better corrosion resistance, they handle damp conditions and regular exposure to the elements well.

316 Grade Stainless Steel

The cream of the crop, 316-grade stainless steel screws are the go-to choice for applications in marine settings. They include molybdenum, further enhancing their corrosion resistance and making them less susceptible to pitting and salt damage.

410 Grade Stainless Steel

While technically part of the stainless steel family, the 410 grade is less resistant to corrosion than the other three grades. However, it's notably stronger and is often used when strength is a primary concern over corrosion resistance.

Practical Ways to Identify Stainless Steel Screws

The crucial question remains: how can you tell if a screw is truly stainless steel? Here are some practical tips to help you avoid the imposter screws.

The Magnet Test

Every stainless steel grade, including 316, can be slightly magnetic if the raw stainless steel was formed using a hot process. Some manufacturers choose to hot process their stainless steel to increase tensile strength without sacrificing corrosion resistance. Cold processed stainless steel is inherently non-magnetic.

However, if a screw is highly magnetic, it's not stainless steel. True stainless steel screws will have very low to no magnetic pulling. This simple test can be a good indicator.

Trust the Seller and Quality Checks

A reliable vendor should be your starting point for sourcing stainless steel screws. Look for vendors with a good reputation and ensure they are transparent about the materials they use. You could ask for a certificate of conformance that states the material used for the screws is stainless steel.

Corrosion Resistance in Practice

After using the screws in challenging environments, you should observe their performance over time. If they show signs of corrosion sooner than you'd expect, it may indicate they aren't the grade of stainless steel claimed.

How Are Stainless Steel Screws Made?

Now that you know how to tell if the screws are made of stainless steel you might be curious about how they are made? The wire passes from a mechanical coil through a straightening device. The straightened wire moves into a machine that cuts it to the needed length and shapes the screw head accordingly. After cold heading, the screws are fed to the thread-cutting machine automatically.

Why Choose Fastener USA for Stainless Steel Screws

At FastenerUSA, we offer a vast inventory of screws with a primary focus on quality and customer satisfaction. Our catalog has various options that are available immediately, and if you don't know what type of screw you need, we will happily assist you!

We also offer free shipping, even to far locations like Puerto Rico and Hawaii. This means you can get what you need without additional costs. Contact us today, and let's partner for your next big project!