垫圈类型说明：用于工业紧固的平垫圈、弹簧垫圈和锁紧垫圈

简介

Washers are small parts, but they often decide whether a bolted joint stays stable, protects the mating surface, or fails because of preload loss, vibration, corrosion, or wrong hardness matching.

For industrial buyers, the key question is not simply “Do I need a washer?” The real question is: which washer type should be used under this bolt or nut — flat washer, spring washer, lock washer, tooth washer, conical washer, or a custom washer?

This guide explains washer types, flat washer uses, spring washer limitations, lock washer selection, material choices, hardness matching, and common purchasing mistakes. It is written for buyers, contractors, distributors, and engineers who need to select washers for real industrial applications rather than only compare part names.

主要内容

What Is a Washer and Why Does It Matter?

A washer is a plate-shaped fastener component placed under a bolt head, screw head, or nut. Its job may look simple, but in a bolted joint it can affect several things:

• Contact pressure under the bolt head or nut
• 表面保护
• Hole coverage
• Preload stability
• Resistance to embedding
• Corrosion compatibility
• Anti-loosening performance
• Electrical contact or insulation
• Sealing or spacing

A common mistake is treating washers as “cheap accessories.” In practice, a washer should be selected together with the bolt, nut, base material, tightening method, and working environment.

For example, a soft washer under a high-strength bolt may deform after tightening. A tooth lock washer may damage a painted surface. A split spring washer may be specified out of habit even when it is not suitable for severe vibration. These are not theoretical problems; they show up as loose assemblies, coating damage, rust marks, uneven clamping, and warranty claims.

XZ Fastener lists industrial washers as a dedicated product category, including flat washers, spring washers, lock washers, fender washers, tooth washers, square washers, conical washers, sealing washers, and custom washers. The available options include carbon steel, stainless steel, brass, aluminum, nylon, rubber, and special materials. You can review washer categories here: Industrial Washers.

Main Washer Types at a Glance

垫圈类型	主要功能	典型用途	Key Risk If Misused
平垫圈	载荷分布和表面保护	General bolted joints, soft materials, slotted holes	Does not lock the joint by itself
Fender / Large OD Washer	更大的承载面积	Thin sheet, wood, plastic, oversized holes	Too large OD may interfere with assembly space
弹簧垫圈	Provides spring effect during tightening	Light-duty assemblies, older designs, non-critical use	Often overestimated as an anti-vibration solution
分体锁紧垫圈	Traditional low-cost locking washer	General hardware, non-critical joints	Poor choice for serious vibration locking
Tooth Lock Washer	Bites into surface	Electrical bonding, grounding, small screws	Damages coating or mating surface
Serrated Washer	Increases friction by serrations	Flange bolts, machinery, moderate vibration	Can mark soft or decorative surfaces
Belleville / Conical Washer	Maintains load with spring deflection	Thermal cycling, preload retention, limited space	Needs correct load-deflection design
Wedge Lock Washer	Mechanical locking by wedge effect	High vibration, dynamic load, heavy machinery	Higher cost; surface marking may occur

The first selection rule is simple: choose the washer by function, not by habit.

Flat Washers: Uses, Strengths and Selection Logic

What Is a Flat Washer?

A flat washer, also called a plain washer, is the most commonly used washer type. It has a flat circular shape with a central hole.

Its main purpose is not to stop loosening. A flat washer mainly provides a stable bearing surface between the fastener and the connected part.

Main Uses of Flat Washers

1. Distributing Load

When a bolt or nut is tightened directly against a soft or thin material, the contact pressure may be too concentrated. A flat washer spreads the load over a larger area.

This is useful for:

• Aluminum parts
• 塑料部件
• Wood assemblies
• 薄金属板
• Painted surfaces
• 长孔
• Oversized clearance holes

If the washer is too small, the bolt head or nut may still bite into the surface. If the washer is too soft, it may deform and reduce preload.

2. Protecting the Mating Surface

Flat washers reduce direct friction between the nut or bolt head and the connected part. This helps protect:

• Painted surfaces
• 镀锌表面
• Stainless steel equipment
• Aluminum frames
• Machinery mounting plates
• Decorative metal parts

This matters when the assembly will be removed and reinstalled, or when visible surface damage is unacceptable.

3. Supporting Oversized or Slotted Holes

Flat washers are often used where holes are larger than the bolt diameter. For slotted holes or soft materials, a larger outside diameter washer is often better than a standard OD washer.

例如：

Hole Condition	Better Washer Choice
Normal clearance hole	标准平垫圈
Large clearance hole	大外径垫圈
长孔	Large OD or structural washer
薄金属板	Fender washer or large OD washer
High-strength joint	硬化垫圈

Flat Washer Standards and Hardness

Common flat washer standards include DIN 125, DIN 9021, ISO 7089, ISO 7090, ISO 7091, ASTM F436, and ASTM F844. XZ Fastener’s washer supply page lists these as common washer standards and also shows hardness options such as HV100, HV140, HV200, HV300, 45H, and 300HV.

The important point for buyers is not only the standard number. It is also the hardness.

一个实用的规则：

Bolt / Screw Strength	Washer Selection Direction
Low-strength general bolt	Standard carbon steel or stainless flat washer
8.8级螺栓	Normal washer may be acceptable depending on design
Class 10.9 or high-preload joint	Consider 300HV or hardened washer
Structural bolt assembly	Follow project standard, such as ASTM F436 or drawing requirement
软质基材	Use larger OD washer, but still check washer hardness

ISO 7089 includes 200 HV and 300 HV plain washer hardness classes, and its scope links washer hardness suitability to different bolt property classes. In simple purchasing language: do not put a soft washer under a high-strength bolt unless the drawing allows it.

When to Choose Flat Washers

Choose flat washers when the goal is:

• 负载分布
• 表面保护
• Stable bearing surface
• Hole coverage
• Reducing embedding
• Matching bolts and nuts in normal assemblies

Do not choose a flat washer if your only goal is vibration locking. A flat washer improves bearing contact, but it does not stop thread rotation by itself.

Spring Washers: What They Can and Cannot Do

What Is a Spring Washer?

A spring washer is designed to provide elastic force. In many markets, the term “spring washer” is used to describe split spring washers, but it can also include wave washers and Belleville washers.

Common spring washer types include:

类型	形状	主要用途
Split Spring Washer	Cut ring with helical form	Traditional low-cost tension support
Wave Washer	Wavy profile	Light preload or axial play compensation
Belleville Washer	Conical disc	Preload retention, thermal expansion compensation

Practical Uses of Spring Washers

Spring washers may still be useful in:

• 轻型组件
• Non-critical equipment
• Low-cost hardware
• Applications following old drawings
• Light vibration where engineering risk is low
• Assemblies where a small spring effect is useful
• Situations where the customer specification requires them

However, a spring washer should not be selected automatically whenever the buyer says “anti-loosening.”

The Important Limitation: Split Spring Washers Are Often Overrated

This is where many general articles avoid making a clear judgment. From a fastener selection point of view, the traditional split spring washer is often misunderstood.

NASA’s Fastener Design Manual explains that a typical helical spring lock washer acts as a spring during tightening, but is normally flat once the bolt is fully torqued; at that point it is equivalent to a solid flat washer and its locking ability is described as nonexistent.

This does not mean every spring washer is useless in every assembly. It means buyers should not rely on a split spring washer as the only locking method for serious vibration, shock load, safety-critical equipment, or high-preload bolted joints.

When Spring Washers Make Sense

Use spring washers when:

• The application is not critical
• The design already specifies them
• The load is light to medium
• Vibration is low
• Cost control matters
• The washer is mainly used as a traditional hardware component

Avoid using split spring washers as the only locking method when:

• The equipment vibrates heavily
• The joint is safety-critical
• The fastener is high-strength and fully torqued
• The surface is hard and the washer cannot bite
• The joint will be inspected for long-term preload reliability

Lock Washers: Not All “Lock” Washers Work the Same Way

What Is a Lock Washer?

A lock washer is a washer intended to reduce loosening. But the word “lock” can be misleading because different lock washers work in different ways.

ASME B18.21.1 covers inch-series helical spring-lock washers, tooth-lock washers, and plain washers, and it specifically notes that “lock” is a historical product term and does not imply permanent locking in every application.

This is a useful warning for buyers: do not assume a washer locks the joint just because the product name includes “lock.”

分体锁紧垫圈

A split lock washer is the most common low-cost lock washer. It is often used in general hardware kits and older machinery designs.

适合于

• General non-critical assemblies
• Light-duty equipment
• Low-cost maintenance
• Existing drawings that specify split washers
• Applications where failure risk is low

Not Suitable For

• High-vibration machinery
• Safety-critical joints
• Heavy dynamic loads
• 精密设备
• High-preload structural bolting

专家判断

Use split lock washers when the specification requires them or when the assembly is low-risk. Do not sell or select them as a serious vibration-locking solution without explaining the limitation.

Tooth Lock Washer

A tooth lock washer has internal or external teeth. The teeth bite into the bolt head, nut, and mating surface.

适合于

• Electrical grounding
• Bonding applications
• 小螺丝
• 薄金属板
• 轻型组件
• Applications where surface damage is acceptable

Not Suitable For

• Painted surfaces
• Decorative stainless steel
• Aluminum surfaces where marks are unacceptable
• Corrosion-sensitive surfaces
• High-strength fatigue-sensitive parts

NASA’s manual notes that tooth lock washers provide some locking action, but they damage mating surfaces; the scratches may increase crack formation risk in highly stressed parts and increase corrosion susceptibility.

专家判断

Tooth washers are useful when biting into the surface is part of the function, such as grounding. They are a bad choice when the surface finish must remain intact.

锯齿锁紧垫圈

A serrated washer has ridges that increase friction under the nut or bolt head.

适合于

• 法兰螺栓
• 机械罩
• Bracket assemblies
• 适度振动
• Applications where surface marks are acceptable

Not Suitable For

• Painted surfaces
• Soft aluminum
• Sealing faces
• Finished visible parts
• Frequently removed assemblies

专家判断

A serrated washer can improve friction, but it still depends on surface hardness, tightening torque, coating, and whether the joint loses preload. It is better than choosing a split washer blindly, but not equal to an engineered vibration-locking solution.

Belleville Washer / Conical Washer

A Belleville washer is a conical spring washer. It is not mainly a “lock washer” in the traditional sense. Its value is in maintaining load when the joint experiences relaxation, thermal expansion, or limited space.

NASA’s manual describes Belleville washers as conical washers used more for maintaining uniform tension load than for locking; unless serrated, they have no significant locking capability.

适合于

• 热循环
• High-temperature assemblies
• 法兰接头
• Battery connections
• Equipment with joint relaxation
• Space-limited preload design
• Assemblies needing controlled spring deflection

Not Suitable For

• Random replacement of flat washers
• Assemblies without load-deflection calculation
• Applications where the washer is flattened beyond its working range

专家判断

Belleville washers are not “better spring washers.” They should be selected by load, deflection, stack arrangement, material, and working temperature.

Wedge Lock Washer

A wedge lock washer uses a pair of washers with cams and serrations. It resists loosening through wedge action rather than relying only on friction.

适合于

• 震动大
• Rail equipment
• Mining machinery
• Wind power equipment
• 工程机械
• Heavy vehicles
• Dynamic load assemblies

Not Suitable For

• Low-cost general hardware
• Decorative surfaces
• Very small assemblies with space limits
• Applications where surface indentation is not allowed

专家判断

If the customer’s main complaint is “bolts keep loosening under vibration,” a wedge lock washer, prevailing torque nut, threadlocker, double nut, safety wire, or redesign may be a better answer than simply adding a spring washer.

Flat Washer vs Spring Washer vs Lock Washer: Practical Comparison

选择点	平垫圈	弹簧垫圈	Lock Washer
主要功能	负载分布	Elastic spring effect	防松动支撑
Best Used For	一般螺栓连接	Light preload support	Loosening-prone joints
Surface Protection	好	有限公司	Often poor if biting type
Vibration Resistance	否	有限公司	Depends heavily on type
可重复使用性	Usually good	Limited after deformation	Depends on design
成本	低	低	Low to high
Best Buyer Question	“Do I need bearing support?”	“Do I need spring deflection?”	“What kind of loosening risk do I have?”

A professional selection should not ask only “flat or spring?” It should ask: What problem is the washer solving?

Washer Material Selection

Carbon Steel Washers

Carbon steel washers are economical and widely used in general construction, machinery, and equipment assembly.

Common Finishes

• 平原
• 镀锌
• 黑色氧化
• 热镀锌
• 磷酸盐
• 达克罗
• 锌铝涂层

最适合

• 室内设备
• 通用机械
• 钢结构
• 建筑五金
• Cost-sensitive projects

注意

Carbon steel washers need suitable coating when used outdoors or in humid environments. Plain steel washers are not suitable for long-term corrosion exposure.

Stainless Steel Washers

Stainless steel washers are used where corrosion resistance matters.

通用等级

• 304 不锈钢
• 316 不锈钢
• A2 stainless steel
• A4不锈钢

最适合

• 户外装备
• Food machinery
• 化工设备
• 沿海环境
• Stainless steel bolt and nut assemblies

专家判断

Use 304 for general corrosion resistance. Use 316 when chloride, seawater, or stronger corrosion risk is present. For stainless assemblies, consider galling risk and avoid unnecessary serrated biting surfaces unless required.

Hardened Washers

Hardened washers are used with high-strength bolts where ordinary soft washers may deform.

最适合

• Class 10.9 / 12.9 bolt assemblies
• 重型机械
• 结构连接
• 高预载接头
• Bolted joints needing stable bearing support

专家判断

If the bolt is high-strength but the washer is soft, the washer becomes the weak point. The joint may lose preload even if the bolt itself is correct.

Brass, Copper, Nylon, Rubber and Plastic Washers

These washers are chosen for special functions, not high-strength clamping.

材质	主要用途
黄铜	Electrical, decorative, corrosion-resistant light-duty use
Copper	Conductivity, sealing, soft bearing surface
尼龙	Insulation, spacing, non-metal contact
橡胶	Sealing, vibration damping, waterproof support
Engineering Plastic	Lightweight, insulation, corrosion separation

Do not use these materials in structural bolting unless the drawing clearly requires them.

如何选择合适的垫圈

Step 1: Define the Real Function

Ask what the washer must do:

要求	推荐方向
Spread load	平垫圈
Protect surface	平垫圈
Cover large hole	Fender or large OD washer
Match high-strength bolt	硬化垫圈
Resist mild loosening	Serrated or tooth washer, if surface damage is allowed
Resist serious vibration	Wedge lock washer or engineered locking method
Maintain preload under thermal cycling	Belleville washer
Provide sealing	Bonded sealing washer or rubber washer
Provide insulation	Nylon or plastic washer
Custom thickness or OD	定制垫圈

Step 2: Match Washer Hardness with Bolt Grade

This is one of the most overlooked details in washer purchasing.

A simple judgment table:

Bolt Grade / Class	垫圈风险	更好的选择
4.8 / 5.8 级	低预载	Standard washer usually acceptable
8.8 级	Medium preload	Check washer hardness and base material
10.9 级	Higher preload	300HV or hardened washer recommended
12.9 级	Very high preload	Hardened washer or specified washer required
Stainless A2/A4	Corrosion focus	Stainless washer, check strength and galling risk
Structural bolt	Safety-critical	Follow project standard exactly

XZ Fastener’s washer page lists washer hardness options including HV100, HV140, HV200, HV300, 45H, and 300HV, which is important when matching washers to different bolt grades and project requirements.

Step 3: Match Coating with Environment

Do not choose washers only by price. Coating should match the actual working environment.

环境	Washer Finish Direction
Dry indoor	普通、黑色氧化、镀锌
General outdoor	Hot-dip galvanized, Dacromet, zinc-aluminum coating
Coastal / marine	Stainless steel 316 or suitable anti-corrosion coating
化工设备	Stainless steel, duplex stainless, or special alloy
High-temperature area	Avoid coatings with unsuitable temperature limits
Electrical grounding	Tooth washer may be used where surface bite is required

NASA’s Fastener Design Manual also warns that plating or coating can become a limiting factor in fastener service temperature and corrosion performance.

Step 4: Consider Surface Damage

Some washers protect the surface. Others intentionally damage it to create grip.

垫圈类型	Surface Effect
平垫圈	Protects surface
大外径垫圈	Protects and spreads load
Tooth washer	Bites into surface
Serrated washer	Marks surface
Wedge lock washer	Serrations may mark surface
Belleville washer	Depends on smooth or serrated type

If the part is painted, polished, passivated, anodized, or decorative, do not use a tooth or serrated washer without approval.

Step 5: Confirm Whether Standard Washer Is Enough

Standard washers are suitable for many applications. But custom washers are needed when the project requires:

• Special outside diameter
• Special inside diameter
• Special thickness
• Non-standard shape
• Special hardness
• 特殊涂层
• 特殊材质
• 承载面积大
• 电气绝缘
• Sealing function
• Drawing-based tolerance

For drawing-based or working-condition-based washer projects, use the 定制紧固件服务. The custom service page lists options such as special materials, corrosion-resistant fasteners, special surface treatments, custom dimensions, and production based on drawings, samples, or working conditions.

Practical Selection by Application

应用	Recommended Washer Choice	原因
通用机械	Zinc plated flat washer	Load distribution and low cost
High-strength bolt joint	Hardened flat washer	Prevent washer deformation
钢结构	Hardened or structural washer	Stable preload and bearing support
Soft aluminum part	Large OD flat washer	Reduce surface indentation
Slotted bracket hole	大外径垫圈	Cover slot and improve bearing area
Electrical grounding	Internal or external tooth washer	Teeth bite through coating for contact
Decorative stainless assembly	Stainless flat washer	Protect surface and corrosion resistance
户外施工	HDG or stainless washer	更好的耐腐蚀性
震动大	Wedge lock washer or lock nut system	More reliable anti-loosening method
热循环	Belleville washer	Helps maintain tension
Waterproof assembly	Bonded sealing washer	Sealing under screw or bolt head

买家应避免的常见错误

Mistake 1: Ordering Only “M10 Washer”

“M10 washer” is not a complete specification. It does not define type, standard, hardness, material, finish, OD, thickness, or function.

Better examples:

• M10 Flat Washer, ISO 7089, 300HV, Zinc Plated
• M12 Spring Washer, DIN 127, Carbon Steel, Black Oxide
• 1/2″ Hardened Flat Washer, ASTM F436, Hot-Dip Galvanized
• M8 External Tooth Lock Washer, Stainless Steel 304
• Custom Large OD Washer, 316 Stainless Steel, Drawing Required

Mistake 2: Using Spring Washers for Every Anti-Loosening Requirement

This is one of the most common procurement habits. Spring washers are cheap and familiar, but they are not a universal vibration solution.

If the application involves high vibration, use a proper locking method rather than simply adding a split washer.

Mistake 3: Ignoring Washer Hardness

A washer that looks correct may still be wrong if it is too soft. Under high bolt preload, a soft washer can embed, flatten, or deform.

This causes:

• Reduced preload
• Loose joint
• Uneven clamping
• Retightening problems
• Possible fatigue risk

Mistake 4: Mixing Coatings Incorrectly

A zinc plated bolt with a plain washer in outdoor use may rust at the washer first. A stainless bolt with a carbon steel washer may create corrosion problems in wet environments.

Washer material and coating should match the bolt, nut, and service environment.

Mistake 5: Using Tooth Washers on Finished Surfaces

Tooth washers work by biting. If the customer does not want coating damage, tooth washers are the wrong choice.

Mistake 6: Treating Washers as Reusable Forever

Some washers can be reused if undamaged. Others should not be reused after deformation, biting, or heavy preload.

Do not reuse:

• Cracked washers
• Flattened spring washers
• Deformed hardened washers
• Tooth washers with damaged teeth
• Corroded washers
• Washers from critical bolted joints without approval

RFQ Checklist for Washer Purchasing

在请求报价之前，请准备以下内容：

项目	需要确认什么
垫圈类型	Flat, spring, lock, tooth, serrated, Belleville, sealing
标准型	DIN, ISO, ASTM, ANSI, JIS, BS, GB, or drawing
尺寸	M6, M8, M10, 1/4″, 3/8″, 1/2″, etc.
内径	Standard or custom
外径	Normal, small, large, oversized
厚度	Standard or custom
材质	Carbon steel, stainless steel, brass, nylon, rubber, etc.
硬度	HV100, HV200, HV300, 45H, hardened, etc.
表面处理	Zinc plated, HDG, black oxide, Dacromet, plain, PTFE
Matching fastener	Bolt, nut, screw, threaded rod, anchor
应用	Machinery, construction, electrical, outdoor, marine, vibration
证书	MTC, inspection report, CO, EN 10204 3.1 if required

XZ Fastener’s main product page states that it supplies bolts, nuts, washers, screws, rivets, anchors, threaded rods, and custom fasteners in DIN / ISO / ASTM / ANSI / EN standards, with materials and coatings including carbon steel, stainless steel, alloy steel, zinc plating, hot-dip galvanizing, black oxide, Dacromet, PTFE, and phosphate. You can browse the full product range here: 所有产品.

For project orders, send the washer type, standard, size, material, hardness, finish, quantity, and application environment through the 联系我们 页。

要点

1. Flat washers are mainly for load distribution and surface protection, not locking. Use them when the joint needs a stable bearing surface or when the base material is soft, thin, slotted, or painted.
2. Spring washers are often overused. A split spring washer may be acceptable in light-duty assemblies, but it should not be treated as a reliable anti-vibration solution for critical joints.
3. Lock washers must be selected by locking mechanism. Split, tooth, serrated, Belleville, and wedge lock washers do not work the same way.
4. Washer hardness must match bolt strength. High-strength bolts often require hardened washers to prevent embedding and preload loss.
5. 材料和涂层应与环境相匹配。 Outdoor, marine, chemical, and electrical applications require different washer choices.

常问问题

1. What is the difference between a flat washer and a spring washer?

A flat washer spreads load and protects the surface. A spring washer provides limited elastic force during tightening. A flat washer is usually better for bearing support, while a spring washer is used in some light-duty or traditional anti-loosening designs.

2. Do lock washers really prevent bolts from loosening?

It depends on the type. Split lock washers have limited locking ability in many fully torqued joints. Tooth washers can provide some locking by biting into the surface, but they damage the surface. For high vibration, wedge lock washers, lock nuts, threadlocker, safety wire, or engineered locking methods are usually more reliable.

3. When should I use a hardened washer?

Use a hardened washer when the bolt preload is high, especially with high-strength bolts such as Class 10.9, Class 12.9, or structural bolt assemblies. A soft washer may deform and reduce clamping force.

4. Are stainless steel washers better than zinc plated washers?

Not always. Stainless steel washers are better for corrosion resistance, especially outdoors, marine areas, or chemical environments. Zinc plated washers are more economical for indoor or mild environments. The best choice depends on exposure, cost, and matching fastener material.

5. Can I use a tooth lock washer on painted surfaces?

Only if surface damage is acceptable. Tooth lock washers work by biting into the surface. They can damage paint, plating, anodizing, or stainless finishes. For painted or decorative surfaces, consider a flat washer with another locking method.

结论

Washer selection should start from the joint problem you need to solve. If the problem is load distribution, choose a flat washer. If the problem is soft material or oversized holes, choose a large OD flat washer. If the problem is high preload, choose a hardened washer. If the problem is thermal expansion or joint relaxation, consider a Belleville washer. If the problem is vibration loosening, do not automatically choose a split spring washer; evaluate tooth, serrated, wedge lock, lock nut, threadlocker, or another engineered locking solution.

For industrial purchasing, the safest washer specification includes type, standard, size, material, hardness, surface finish, and application environment. A washer is not just an accessory. It is part of the complete fastening system, and the wrong washer can make the right bolt perform poorly.

For standard and custom washer sourcing, review Industrial Washers, browse 所有产品, or submit special dimensions and working conditions through 定制紧固件服务.