Stainless Steel Fastener Suppliers

Surface Treatment Process of Stainless Steel Fastener and Its Effect on Service Life

Stainless steel fasteners are widely used in various industrial fields due to their excellent mechanical properties and corrosion resistance. However, even stainless steel is not completely immune to environmental factors such as oxidation, rusting, or surface contamination. To further enhance the durability and service life of stainless steel fasteners, appropriate surface treatment processes play a critical role. This article explores the commonly used surface treatment technologies for Stainless Steel Fastener Suppliers and discusses how these treatments affect their performance and longevity, with special reference to Jiangsu Jiajie Special Screw Co., Ltd., a leading manufacturer in this field.

Overview of Jiangsu Jiajie Special Screw Co., Ltd.
Established in 2008 with a registered capital of 50 million yuan, Jiangsu Jiajie Special Screw Co., Ltd. has grown into a professional enterprise specializing in stainless steel products. The company operates two plants—one new plant covering 40,000 square meters and an older one occupying 20,000 square meters—located in Dainan Town, a renowned stainless steel production hub in China. With more than a decade of experience, the company produces high-quality stainless steel fasteners using materials such as SUS301, SUS304, and SUS316, which are known for their superior corrosion resistance and mechanical strength.

Jiangsu Jiajie offers a comprehensive range of products, including external hexagonal screws, internal hexagonal screws, hexagonal nuts, washers, tapping screws, machine screws, tooth screws, flange fasteners, pipe fittings, non-standard fasteners, and stainless steel wire. All products comply with international standards such as GB, DIN, and ISO. These fasteners are widely applied in industries like photovoltaics, construction decoration, marine engineering, machinery, petrochemicals, shipbuilding, and rail transit. The company’s annual output reaches 80,000 tons, reflecting its strong production capacity and market demand.

Importance of Surface Treatment in Stainless Steel Fasteners
Although stainless steel inherently possesses good corrosion resistance, the surface condition of fasteners significantly affects their long-term performance. Surface treatment processes can improve corrosion resistance, reduce friction, enhance appearance, and prevent galling or seizing during installation. Therefore, choosing the right surface treatment method is crucial for extending the service life of SUS301 Fasteners, especially when used in harsh environments such as high humidity, salt spray, or chemical exposure.

Common Surface Treatment Processes
1. Passivation
Passivation is one of the most common and effective surface treatments for stainless steel. It involves immersing the fasteners in a nitric acid or citric acid solution to remove free iron from the surface and promote the formation of a dense chromium oxide layer. This passive film acts as a barrier against corrosive elements. At Jiangsu Jiajie, passivation is a standard post-processing step for all SUS304 and SUS316 fasteners, ensuring that they meet industry requirements for corrosion resistance and surface cleanliness.

2. Electropolishing
Electropolishing is an advanced electrochemical process that removes a thin layer of metal from the surface, resulting in a smoother and brighter finish. This treatment not only improves aesthetics but also enhances corrosion resistance by eliminating micro-roughness and embedded contaminants. Jiangsu Jiajie employs electropolishing for fasteners used in medical devices and food processing equipment, where hygiene and cleanability are paramount.

3. Black Oxide Coating
Black oxide is a conversion coating formed by a chemical reaction between the steel surface and oxidizing salts. Although it does not provide the same level of corrosion protection as passivation or electropolishing, black oxide improves wear resistance and reduces light reflection. This makes it suitable for applications in machinery and automotive components. Jiangsu Jiajie applies black oxide coatings selectively based on customer requirements and application conditions.

4. PTFE Coating
PTFE (polytetrafluoroethylene) coatings offer excellent anti-galling properties and low friction coefficients. They are often applied to threaded fasteners to facilitate assembly and disassembly while preventing damage to mating surfaces. In industries such as aerospace and rail transit, where precision and reliability are essential, Jiangsu Jiajie provides PTFE-coated fasteners that ensure smooth operation under high-torque conditions.

5. Electroplating
While less common for  SUS304 Fasteners due to their inherent corrosion resistance, electroplating with zinc or nickel may be employed for decorative purposes or additional protection in specific environments. Jiangsu Jiajie performs selective electroplating on certain product lines to meet customized client needs, particularly in architectural and decorative applications.

Impact of Surface Treatment on Service Life
The effectiveness of surface treatment directly influences the service life of SUS316 Fasteners. For example:

Passivated fasteners exhibit significantly better resistance to atmospheric corrosion and mild chemicals.
Electropolished surfaces have fewer micro-cracks and crevices, reducing the risk of pitting and stress corrosion cracking.
Coated fasteners , such as those with PTFE or black oxide, demonstrate improved performance in terms of wear resistance and ease of use.
Properly treated fasteners maintain dimensional stability and mechanical integrity over extended periods, even under cyclic loading or temperature variations.
At Jiangsu Jiajie, rigorous quality control measures are implemented throughout the surface treatment process to ensure uniform coverage, adhesion, and performance consistency. The company conducts regular salt spray tests, tensile strength assessments, and surface roughness inspections to verify the effectiveness of each treatment method.

Surface treatment plays a vital role in enhancing the functional performance and extending the service life of stainless steel fasteners. As a professional manufacturer, Jiangsu Jiajie Special Screw Co., Ltd. integrates advanced surface treatment technologies into its production process to deliver high-quality fasteners that meet the diverse needs of global markets. Whether in photovoltaic installations, marine engineering, or transportation infrastructure, properly treated stainless steel fasteners from Jiangsu Jiajie provide reliable, long-lasting performance, making them a preferred choice for engineers and procurement professionals alike.