Stainless Steel Flat Washer

Product Introduction

A stainless steel flat washer (also called a stainless steel flat washer or washer) is an annular metal plate placed between the head of a bolt, nut, or screw and the connected part. It is usually made of austenitic stainless steel (such as 304/A2 or 316/A4) and conforms to standards such as GB/T 97.1 (standard type), GB/T 96 (large series), and GB/T 97.2 (chamfered type), with nominal sizes covering M1.6–M64. Its core function is to use its own elasticity and rigidity to increase the contact area between the fastener and the connected part, distribute pressure, protect the surface of the connected part from damage, and serve as an important auxiliary component in a stainless steel fastener system, providing excellent corrosion resistance matching that of bolts and nuts.

I. Product Features

Corrosion resistance inherent to the material: Made of 304 (A2) or 316 (A4) stainless steel, it resists corrosion through the dense passive film on the material surface. The surface is usually a clean natural finish or has been passivated, with no additional electroplating required.

No risk of hydrogen embrittlement: Because no electroplating process is used, the hidden risk of hydrogen embrittlement fracture in high-strength fasteners (such as grade 10.9 and above) caused by electroplating is completely avoided.

Good surface quality: After stamping, the edges are smooth and the surface is clean. Burrs are not easily generated during tightening, reducing scratches on the paint or soft materials of the connected parts.

Diverse types and specifications: Common types include standard type (moderate outer diameter), large series (larger outer diameter, wider bearing surface), chamfered type (inner hole with chamfer to prevent stress concentration), as well as square and special shapes, adapting to different assembly requirements.

Non-magnetic/weakly magnetic characteristics: Austenitic stainless steel flat washers are usually non-magnetic or weakly magnetic, making them suitable for electronic or medical equipment sensitive to magnetism.

II. Product Advantages

Excellent weather resistance and maintenance-free performance: In outdoor, humid, or mildly corrosive environments, stainless steel flat washers will not rust and produce yellow water like carbon steel washers, avoiding contamination of connected parts. They have a long service life and are almost maintenance-free.

Protection of connected parts: By distributing the local compressive stress of the bolt head or nut, they effectively prevent wood, aluminum alloy, plastic, or painted thin plates from being crushed or scratched during tightening.

Anti-loosening cooperation: When used with stainless steel bolts and nuts, the flat surface of the washer provides a stable friction surface, helping to transmit torque stably. When used with spring washers, it prevents the spring washer from scratching the workpiece.

Low whole-life cost: Although the unit price is higher than zinc-plated carbon steel washers, in outdoor or corrosive environments (such as photovoltaics, curtain walls, ships), the cost of frequent replacement and anti-corrosion maintenance is eliminated, resulting in higher overall benefits.

III. Scope of Application

Food, medical, and pharmaceutical equipment: 304 or 316 material is preferred; the surface is smooth and easy to clean, resistant to disinfectant corrosion, and meets hygiene standards.

Marine engineering and ships: Offshore platforms, ship fittings, yacht hardware, etc. It is recommended to use 316 (A4) material to resist high salt-spray environments.

Photovoltaics and outdoor construction: Photovoltaic support connections, curtain wall keels, outdoor railings and handrails, etc., balancing corrosion resistance and aesthetics.

Chemical and environmental protection equipment: Fastening points such as reactors and pipeline flanges that come into contact with chemical media such as acids, alkalis, and salts.

Precision electronics and instruments: Equipment sensitive to magnetism, electronic instruments, and cleanroom environments requiring contamination prevention.

General industrial assembly: Fixing of components in various stainless steel equipment, and use in combination with stainless steel bolts and nuts.