China Flat Washers Manufacturers Suppliers Factory

Jiangyin Xianggu Hardware Products: a Leading Professional Flat Washers Manufacturer in China

We have specialized in manufacturing various types of Spring Washers for many years. By doing business with us, you can gain:

Complete Product Range

Our company can provide various stainless steel, carbon steel, copper Hex Bolts, Flange Bolts, Hex Socket Head Screws, Hex Nuts, Spring Washers, Flat Washers and other fasteners. We also offer a variety of coating treatments, such as hot-dip galvanizing, Dacromet, blue-white zinc, yellow zinc.

Professional Management System

Our company is committed to integrating the advantageous supply chain system of various fastener products, focusing on the sales staff's mastery of professional knowledge of fasteners, and aims to provide customers with fastener system solutions.

Rich Experience

We have been working with customers from various countries and industries for many years, so the experience is very rich. We are willing to be your partner with first-class product quality, first-class service level and competitive price.

Wide Range of Product Applications

Our fasteners are widely used in automobiles, ships, wind energy, solar energy, boilers, electronic appliances, mechanical equipment, construction engineering and other fields.

Square Flat Spring Washer
Square Flat Spring Washer, also known as Square Spring Washer or Square Section Washer, is a mechanical component used in a variety of applications to provide a secure, tight connection between two
Flat Spring Washer With Square Ends
Flat Spring Washer With Square Ends is a highly versatile and effective tool for any application requiring a safe and secure fastening solution.
Heavy Washer
With our expertise in this field, we are able to manufacture and supply high-quality Heavy washers. Our products are made of high-quality materials sourced from the most trusted and reliable
Flat Washer
A flat washer is a thin ring with a circular outer diameter and a central hole (inner diameter), and its size is only larger than a bolt or screw.
Countersunk Washers
Countersunk Washers are made of stainless steel. These turned washers are ideal for design/aesthetic sensitive applications. Unlike standard flat washers, they have a tapered countersunk hole for the
Spherical Washers
Spherical washers are designed to help uniform tightening between irregularly aligned parts. The top washer (C) has a convex spherical radius for alignment with the concave bottom washer (D).
Hardened Steel Washers
Hardened steel washers provide a smooth bearing surface for use under the heads of bolts and/or nuts.
Stainless Steel Flat Washers
Use these metric washers to evenly distribute the load under bolt or screw heads and nuts when fastening. They can also act as spacers.. Stainless steel washers are more corrosion resistant than
Carbon Steel Plain Washer
Steel washers are stronger and more wear resistant than stainless steel washers. Steel washers without a plating or coating are best for dry environments, since moisture will cause them to rust.
Heavy Washers
Designed for use with A325 structural screws, studs, and nuts, these washers are often used for construction and exterior building applications.. Hot-dipped galvanized washers are corrosion resistant
Oversized Washer
Compared to our general purpose washers, these have exaggerated diameters and/or thicknesses for covering oversized holes or for use as spacers and levelers.. Black-oxide steel washers have mild
Zinc SAE Washers
316 stainless steel washers have excellent resistance to chemicals and salt water. They may be mildly magnetic.. 18-8 stainless steel washers have good chemical resistance and may be mildly magnetic.

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Brief Introduction to Flat Washers

Also known as plain washers, flat washers spread the load on a fastener while reducing heat and friction during the tightening process. Flat washers prevent the bearing surface from sinking under load, especially when the contact area of the fastening object is small and the fastening object is made of soft materials such as aluminum and resin. Flat washers are also used as gaskets, which are common in industrial and household applications. Such washers are available in metal and plastic materials. For electrical insulation, plastic flat washers are often used because metal washers act as conductors.

Key Features of Flat Washers

Strong Reliability

Flat washers are used to increase the bearing surface of a nut or fastener head, thereby spreading the clamping force over a larger area. They are useful when working with soft materials and oversized or irregularly shaped holes. The sturdy metal construction ensures long-term reliability in the application.

Various Materials and Surface Treatments

Flat washers are typically made from a variety of materials, including aluminum, brass, nylon, silicon bronze, stainless steel, and steel. Unplated or uncoated steel (called a "plain finish") has not been surface treated to prevent rust other than a thin layer of oil for temporary protection. Therefore, common steel surface treatments are galvanizing and hot-dip galvanizing.

Strong Durability

After surface treatment, these flat washers become more resistant to corrosion, ensuring long-term durability. For example, in a corrosive environment, stainless steel can form its self-healing, corrosion-resistant chromium oxide film when it encounters oxygen. This feature allows flat washers to play an important role in a variety of harsh industrial applications.

Various Sizes

The washer size refers to its nominal hole size and is based on the screw size. Its outer diameter (OD) is always larger. Dimensions and outside diameters are usually expressed in fractions of inches, but decimal inches may also be used. Thickness is usually listed in decimal inches. These sizes are customizable to your specific needs, meaning you can choose the right size flat washer for different applications.

Benefits of Flat Washers

Load Distribution

By spreading the load on a threaded fastener, flat washers ensure that one particular point is not subjected to excessive stress. This feature is particularly useful when bolts or screws are fastened to soft materials. Spreading the load prevents fasteners from digging into the material or causing potential damage.

Prevent Leaks

In pipes and hydraulic systems, flat gaskets (especially those made of rubber or other flexible materials) act as seals. They prevent liquids from escaping, ensuring the efficiency and safety of the system. Even the smallest leak can escalate into a serious problem, resulting in wasted resources and potential danger.

Protection and Insulation

Flat washers can also act as insulators, especially when they are made of non-conductive materials. In electrical applications, this insulation protects against accidental circuitry or potential short circuits. Additionally, they protect surfaces from being scratched or damaged by the turning action of nuts and bolts.

Enhance Grip and Reduce Vibration

Some flat washers, especially those designed with serrations or spring-like structures, can grip surfaces. This grip reduces the chance of the fasteners coming loose due to vibration. This capability is invaluable for machinery or applications where constant motion is the norm.

Compensating for Oversized or Misaligned Holes

Sometimes, the holes drilled for fasteners may not line up perfectly or may be larger than required. In these cases, flat washers can compensate for such differences, ensuring the fasteners fit snugly and function optimally.

Different Types of Flat Washers

There are different types of flat washers suitable for different applications. See below for descriptions of each.

Fender Washers

Due to their large outside diameter (OD), fender washers provide an extra wide support surface, which is useful when working with oversized or irregularly shaped holes and when fastening soft materials that would benefit from added support.

Machine Screw Flat Washers

Machine screw flat washers are the smallest type of flat washers because their outside diameter (OD) is typically only slightly greater than twice their inside diameter (ID).

Mega Thick Flat Washers

Mega thick flat washers are extra thick, with thicknesses ranging from 0.100" to 0.313", making them useful for spacing applications. It is generally available in SAE and USS models.

SAE Flat Washers

SAE flat washers provide a tighter thread fit, are thinner, and have a smaller outside diameter (OD) than comparably sized USS washers. Hardened SAE flat washers with Grade 5 and 8 hex screws are recommended.

Square Plate Washers

Square plate washers are large, thick, and flat and are typically used in structural bolting applications.

Structural Flat Washers

Structural flat washers are used in exterior construction applications and in the construction of A325 bolts, studs and nuts.

Thick Flat Washers

Thick Flat Washers are thicker than standard washers and range in thickness from 0.072" to 0.146", which allows them to be used as gaskets. They are generally available in SAE and USS models.

T-Slot Washers

T-slot washers are flat washers with a beveled edge and approximately the same outside diameter (OD) as an equivalent SAE washer, but are approximately twice as thick as their SAE counterparts. T-Slot Washers are typically used with T-Slot Bolts but can also be used as gaskets due to their thickness. T-Slot Washers are heat treated (where indicated) for added strength.

USS Flat Washers

USS flat washers offer a looser thread fit, are thicker, and have a larger outside diameter (OD) than comparably sized SAE washers. The oversized holes in the USS washers are too large to properly support the bearing surfaces of Class 5 and Class 8 hex head screw heads, while the smaller one washer size will be too tight and may cause the screw head to fail.

Common Uses of Square Flat Washers

Washers are the fastening industries’ load distributors. When they’re manufactured as conservatively shaped discs, they protect the area around an inserted bolt by augmenting the diameter of that fastener head. Square flat washers serve the same purpose, but they also take that principle in a different direction. They’re shims and turn-resistant anchoring products. Having touched upon a few simple applications, just what are the common uses of square flat washers?

Squarish Shims Fill Space
That’s right, while disc washers are operating solely as load distributors, square flat washers are serving a second role. Their thick metal forms have that standard bolt opening in the centre, plus a wide surface area, a feature that spreads torque and head load, but they also perform as shims. That means the bolt crown can be lifted away from the anchored part. It also means that a multi surface project won’t deform or bend when the fastener is tightened, not when these shimming washers are interposed between more than two anchoring parts. If there is an open space in the coupling join, the zone between the bolt head and the nut at the other end of the fastener rod, the squared shim washers occupy that space and act as a force-countering join segment. Employed in the construction industry and complex parts mating scenarios, this bushing or packing feature keeps multiple join surfaces deform-free.

Non-Rotating Fixtures
When a narrow structural frame employs a restrictive series of elongated channels, there are advantages to be gained when the underlying fastener parts lock. Special locking nuts are half the battle here, yet there’s still that spinning washer disc to deal with, isn’t that right? Well, square flat washers solve that spinning headache by using their flat edges as an anchor. Placed below the bolt head and under the nut, the fastener is already partially locked. Just screw the nut tight to complete the fastener’s journey. Of course, this may sound like a rudimentary product attribute, but it’s one that becomes invaluable when square structural tubing is employed on a building project. Due to their flat sides, square flat washers are also commonly used in complex machine housings. High-vibration machinery, mine screening equipment and commercial washing machines, as just two examples of this application practice, use the flat, square fastener parts in restrictive spaces to ensure anchoring reliability, even when those vibrational forces try their best to loosen the bolt. Narrow vehicle crevices, square tubing, construction frame components, all of these applications and more benefit when shim-capable square flat washers are called into service.

Two Common Standards for Flat Washers

USS

The name USS is derived from the name of the "Unified Standard Series" when coarse threaded fasteners were also called USS bolts. Many people believe that USS flat washers are intended for use with "USS" coarse thread bolts. This is not the case and is incorrect for many applications. USS standard flat washers are suitable for applications involving compressible materials such as wood, thin sheet metal, etc. Their outside diameter is wide enough to provide a large surface area to prevent the bolt head from digging into the material and minimize joint compression. At the same time, their inner diameters are large enough to accommodate bolts with very loose tolerances.

SAE

Since the Industrial Revolution, more equipment and machines are made of steel, which is not as compressible as wood. Therefore, the smaller, more compact SAE standard flat washer was developed and named after the Society of Automotive Engineers. The inside diameter of an SAE flat washer is closer to the diameter of the bolt size it is mated to because today's bolts are manufactured by machine from cold forming to hot heading to tight tolerances. The SAE flat washer also has a smaller outside diameter because it does not require as large a load-bearing surface area to prevent compression as USS washers do for compressible materials.

Factors to Consider When Choosing the Right Flat Washer

When used with bolts and nuts, you should consider the following factors when choosing flat washers:

Material

When selecting gasket materials, attention should be paid to the electrochemical corrosion of different metals. The material of the flat pad is generally the same as that of the connected parts, usually steel, alloy steel, stainless steel, aluminum alloy, etc. Copper and copper alloys can be used when conductive requirements are required.

Size

The inner diameter of the flat washer should be selected based on the larger diameter of the thread or screw. The connection material should be soft (such as composite materials) or matched with spring washers, and a larger outer diameter should be selected.

Installation Location

When the washer is placed on the bolt or screw head, in order to prevent the fillet under the head from interfering with the washer, a flat washer with an inner hole chamfer can be used.

Specific Application

Steel flat washers should be used for important large diameter bolts or when increasing anti-extrusion force. Steel flat washers should also be used for tension bolt or tension-shear composite bolt connections. For special requirements, you should use special gaskets. For example, copper gaskets can be used for conductive parts, and sealing flat washers can be used for applications that require air tightness.

DIY Tips: When and How to Use Flat Washers Effectively

Flat washers might seem like small, inconspicuous pieces of hardware, but they play a crucial role in many DIY projects. Whether you’re assembling furniture, repairing household items or building a treehouse, knowing when and how to use flat washers can make all the difference in ensuring your projects are sturdy and long-lasting. The following content will cover some basic tips to help you use flat washers more effectively.

Understand Their Purpose
At their core, flat washers are designed to distribute the pressure of a nut or bolt evenly over a surface, preventing damage and ensuring a tighter fit. They also help reduce friction when tightening, and in some cases, they can prevent corrosion between dissimilar metals.

Select the Right Material
Flat washers come in a variety of materials including steel, stainless steel, brass, copper and even plastic. Your choice should depend on the application:
●Steel and Stainless Steel: Great for most general-purpose applications. Stainless steel offers better corrosion resistance.
●Brass and Copper: Typically used in situations where corrosion is a concern, or a softer metal is needed to prevent marring a surface.
●Plastic: Ideal for electrical insulation or when a non-conductive washer is required.
We would recommend using Stainless Steel as they offer the most beneficial features and it suits most projects.

Size is Key
Ensure your washer fits snugly around your bolt or screw. The inner diameter of the washer should be slightly larger than the diameter of your fixing. Too big, and it may not serve its purpose; too small, and it might not fit.

Layering Washers
In some DIY situations, you might find it beneficial to use multiple washers. This can provide extra spacing, distribution of pressure, or even added aesthetic appeal.

Use with Wooden Projects
When working with softwoods or thin pieces of lumber, flat washers are essential. They prevent bolts and screws from digging into the wood, which can weaken the material over time.

Prevention of Galvanic Corrosion
If you’re using a bolt of one metal and attaching it to a material of another metal, a washer can act as a barrier, preventing the two metals from reacting with each other.

Re-check Tightness After Time
Over time, as materials settle or are exposed to various environmental factors, the tightness of a bolt can change. Every so often, give a quick check to your bolted connections to ensure they’re still snug.

Storage Tips
Keep an organised collection of washers in various sizes and materials. This ensures you always have the right washer on hand for the job. Little compartmentalised storage boxes or magnetic trays can be handy for this purpose.

Washers in Motion
For any parts that will have movement (like a swinging gate or door), washers can help reduce wear over time by acting as a buffer between the moving parts.

When in Doubt, Use Them
If you’re unsure whether a washer is necessary, it’s typically better to use one. The added distribution of pressure and protection they provide is often worth the minor additional effort.

Difference Between Flat Washer and Spring Washer

Application Advantages

lat Washers

The main advantage of using flat washers is that they help distribute the load evenly across the surface material, thereby reducing the risk of damage or deformation. They are inexpensive and easy to source, making them ideal for low-cost applications. Additionally, they can be stacked together to form thicker gaskets for applications requiring additional thickness.

Spring Washers

The main advantage of spring washers is that they provide superior tension control, maintaining a tight connection even under vibration or movement. They are also better suited for high load applications as they are designed to withstand greater tension. Additionally, spring washers can be reused multiple times, which makes them ideal for repair work.

Design

Flat Washers

Flat washers are simple in design and consist of a flat, thin metal plate with a hole in the center. It is inserted via threaded fasteners. When a fastener is driven into an object, the flat washers will distribute its load. Regardless, they are flat. If the washer is flat, it is considered a flat washer.

Spring Washer

A spring washer is a washer with a curved shape. Unlike flat washers, they are not flat. The spring washer is curved. They can flex in different ways, but all spring washers have a curved shape that prevents them from sitting flush with the surface without load.

Testing Equipment

We use the following equipment to test our products to ensure they meet high quality standards：

productcate-700-1015

Factory Photos

The picture below is our production workshop:

productcate-700-529

Frequently Asked Questions

Q: Should I use spring washers or flat washers first?

A: Install the spring washer onto the bolt first, then the flat washer onto the bolt. When the nut is tightened, the spring washer distributes the pressure over a larger surface area, preventing damage to the softer material.

Q: Can flat washers prevent loosening?

A: Flat washers do not have a locking function but are used to protect the mating surface from damage. They do this by increasing the surface area to help distribute loads, especially on soft materials or on large or slotted holes.

Q: What are the three main types of washers?

A: The three main types of washers are flat washers, spring washers, and lock washers.

Q: Are flat washers necessary?

A: Yes, the main function of the flat washer is to increase the load-bearing surface area of the screw and reduce the surface pressure exerted on the fastened object. Looseness occurs when the bearing surface sinks under surface pressure, so using flat washers to reduce surface pressure is very effective.

Q: What are the most common standard flat washers?

A: USS and flat washers are the two most commonly used flat washers. SAE flat washers are Type A narrow washers with smaller outside diameter dimensions and are thinner than typical USS washers. USS flat washers, on the other hand, are wide A-type washers.

Q: What is a stainless steel flat washer?

A: 304 stainless steel flat washer is a circular outer diameter sheet with a center hole (inner diameter) stamped to the size of a bolt or screw. Used to evenly distribute fastener pressure. A flat surface area that can be used as a nut or bolt to tighten.

Q: Do flat washers have a direction?

A: If one side has serrations, that side should go down (away from the nut). If the washer is slightly domed, it should be dome side up. Standard flat washers should be oriented with the flat side up. These small, circular pieces of hardware play a critical role in fastening applications.

Q: Are flat washers hardened?

A: Some flat washers are hardened to add extra strength and protection and are the recommended washers for any fastener except mild steel bolts.

Q: What are the common materials for flat washers?

A: Common flat washer materials include steel, stainless steel, brass, and plastic.

Q: What are the sizes and specifications of flat washers?

A: Flat washers come in a variety of sizes and specifications, depending on their purpose. Its dimensions include parameters such as inner diameter, outer diameter and thickness.

Q: What is the difference between flat washers and lock washers?

A: Flat washers are primarily used to disperse pressure, while lock washers are designed to provide additional resistance to prevent the fastener from loosening.

Q: Why are flat washers necessary in some applications?

A: In some applications, fasteners may be subject to extreme forces or vibrations, and using flat washers can help mitigate these effects and extend the reliability of the connected components.

Q: What are the applications of flat washers in the automotive industry?

A: In the automotive industry, flat washers are commonly used in fasteners for components such as engines, suspension systems, and braking systems to improve the reliability and durability of connections.

Q: How do you choose the right flat washer for a specific application?

A: When selecting the right flat gasket for a specific application, factors such as material, size, environmental conditions and required performance characteristics need to be considered to ensure it performs effectively. Please refer to the above content for details.

Q: What is the smallest flat washer?

A: Machine screw flat washers are the smallest flat washers. Its outside diameter is usually only slightly larger than twice its inside diameter.

Q: Are there grades for flat washers?

A: Flat washers themselves are not specified by grade, except for structural washers that meet ASTM (American Society for Testing and Materials) standard F436.

Q: What are the dimensions of an M20 flat washer?

A: M20 flat washers measure 20mm x 45mm x 3mm and are commonly used to distribute the load of nuts and bolts.

Q: Why choose flat washers?

A: Flat washers are invaluable components in both mechanical and everyday setups, offering a multitude of benefits despite their simple design. Their primary function is to distribute the load of a bolt head or nut uniformly, preventing it from pulling through softer materials like wood or plastic. Beyond load distribution, they shield surfaces from potential damage during the tightening process, serve as spacers or shims for precise alignment and reduce the adverse effects of vibration, ensuring that fastenings remain secure even with motion or intermittent shocks. Furthermore, when different metals are in contact, washers can deter galvanic corrosion by acting as a protective intermediary. Their utility also extends to aesthetics, providing a polished finish by hiding misaligned or oversized holes, and to functionality by increasing the bearing surface in softer materials and optimising tightening efficiency by minimising friction. In essence, flat washers, though seemingly inconspicuous, play a critical role in ensuring the durability and efficacy of various applications, making them indispensable to both DIY enthusiasts and professionals.

Q: Why are washers used with screws?

A: A screw is a threaded fastener, and it’s here where washers really show their worth. Without a washer, a screw can damage the joint’s bearing surface when its threads dig into the material during tightening. Screw washers distribute the load. This is especially necessary when you’re driving into a soft material, such as wood or aluminium, which is vulnerable to stress-related damage. Washers for screws provide the resistance to the stress caused by the load. Screws with washers not only prevent damage, but also movement and corrosion.

Q: Why are washers used with bolts and nuts?

A: For the same reason they’re used with screws. Nuts and bolts add a particular challenge, however. If you don’t use a washer, the hexagonal shape of the nut and bolt can leave an indentation in the bearing surface. Washers for bolts prevent this from happening. A flange-headed bolt and nut present an alternative to a nut and bolt washer. The flange takes on the job of bolt washers, distributing the load and preventing damage.

Q: How to use washers?

A: The first thing to check when using a washer is that you have chosen one of the right thickness. A thicker washer will help when you have an assembly that needs a little extra tightness - you may even need more than one washer in such cases. When waterproofing is your main aim, a thinner washer may suffice. It is essential to measure the size of the washer. Using one that is either too large or too small will adversely affect the joint. It is also wise to grease your washers. This makes it easier to put the fastener in place, as well as helping to prevent corrosion. The use of washers is generally very easy, provided you follow these simple guidelines. Doing so will go a long way towards securing your assembly and ensuring that it lasts longer.

Q: When not to use washers?

A: ●You have uniform material; fastened components are the same material, and there are no concerns with surface damage.
●Your fastener has a large bearing surface.
●Vibration and other environmental factors aren’t a concern.
●Your joint has limited space for a washer.
●You can use a Place bolt instead.

As one of the most professional flat washers manufacturers and suppliers in China, we're featured by customized hardware products made in China. Please rest assured to buy or wholesale high quality flat washers for sale here from our factory. For price consultation, contact us.

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