Hardened Flat Washers for High-Strength Bolted Joints

A high-strength bolt deserves more thought than simply grabbing the first washer that fits over the thread. Bremick Metric High Tensile Washers provide hardened washer support for compatible metric bolted connections where the washer needs to suit the strength, dimensions & specification of the fastening assembly.

Also described as high tensile flat washers, metric hardened washers & hardened flat washers, these fasteners are used where a general-purpose mild steel washer may not meet the requirements of the joint. They're particularly relevant when working with compatible Class 8.8 & Class 10.9 high tensile bolts, machinery, fabricated steel & other higher-strength metric fastening assemblies.

Building the complete connection? Compare Bremick High Tensile Bolts & the wider Nuts & Washers range before ordering.

What Are Bremick Metric High Tensile Washers?

Metric high tensile washers are hardened flat washers intended for compatible higher-strength metric bolted assemblies.

They can be positioned beneath a bolt head, nut or both where required by the connection.

A correctly selected high tensile washer can:

► Provide a suitable hardened bearing surface
► Spread clamping force across the connected material
► Support compatible high-strength bolt assemblies
► Reduce concentrated bearing directly beneath a bolt head or nut
► Provide the dimensions required by the specified connection

The important distinction is that a high tensile flat washer shouldn't automatically be treated as an ordinary flat washer with a different finish.

Its dimensions, hardness, material & finish need to suit the assembly.

For everyday applications where a general-purpose washer is specified instead, compare Flat Washer.

Why Choose Bremick Metric High Tensile Washers?

Match the Washer to the High-Strength Fastener

Think of the connection as a complete assembly:

Bolt | Nut | Washer | Connected Material

Each component has a job.

Carefully choosing a Class 8.8 or Class 10.9 bolt while treating the washer as an afterthought can leave an avoidable mismatch in the joint.

Hardened Flat Washer Construction

Australian fastener terminology commonly uses high tensile washer, high tensile flat washer & hardened flat washer for this category.

The hardened construction is what separates these washers from many ordinary commercial flat washers used across lighter general fastening work.

Metric Sizes for Metric Fasteners

These washers are selected around metric bolted connections.

An M12 washer belongs in an appropriately specified M12 assembly, while larger M16, M20 & M24 connections require washers matched to their respective fastener systems.

Don't select from outside diameter alone.

Useful Bearing Surface

Where specified, the washer creates a bearing surface between the rotating fastener component & the connected material.

Correct washer dimensions help distribute bearing forces across the intended area rather than concentrating them immediately beneath the bolt head or nut.

Common Applications

Machinery & Equipment Mounting

Machine bases, frames, guards, brackets & equipment assemblies can use high-strength metric fasteners where substantial clamping forces are involved.

If the assembly calls for a hardened washer, match it to the bolt system rather than substituting a standard flat washer because it happens to fit.

Fabricated Steel Assemblies

Picture a fabrication bench with three washer bins sitting beside the job.

All three fit over the bolt.

Only one matches the drawing.

That's why experienced fabricators check the fastener schedule before deciding that similar dimensions mean interchangeable hardware.

For connections involving specified high-strength steel fasteners, browse Structural Fasteners & Bolts.

Plant Maintenance

Shutdown work has a habit of turning organised hardware into one large bucket.

Avoid it.

When dismantling higher-strength bolted connections, keep bolts, nuts & washers identified by equipment location or joint.

Reassembly becomes much easier when nobody has to work backwards from a pile of unidentified washers.

Heavy Workshop Repairs

Replacing a missing washer from a high tensile bolt?

Look at what's already in the assembly.

Check:

► Metric bolt diameter
► Bolt property class
► Nut specification
► Existing washer type
► Washer dimensions
► Finish
► Connected material
► Equipment requirements

The surviving hardware can provide useful clues, but documented specifications should take priority where available.

Construction & Steelwork

High tensile washers can appear in construction & fabricated steel applications, but that doesn't make every hardened washer a structural washer.

Where a drawing, engineer or bolting specification nominates a particular washer standard, use the specified product.

Agricultural & Industrial Equipment

Frames, machinery supports, guards & fabricated components across agricultural & industrial equipment can use metric high-strength fastening assemblies.

Vibration, repeated maintenance & exposure can make correct hardware identification particularly valuable when replacing fasteners later.

Product Selection Guide

Which High Tensile Washer Do You Need?

Don't start with the washer bin.

Start with the connection.

Identify the bolt diameter

M8, M10, M12, M16, M20, M24 or another metric size?

Check the bolt property class

Is the assembly using Class 8.8, Class 10.9 or another specified fastener?

Confirm washer inside diameter

The ID needs to suit the nominated bolt.

Check outside diameter

OD determines the washer's bearing footprint.

Check thickness

Washers with similar nominal sizes can have different thicknesses depending on type & specification.

Confirm hardness or standard

If a hardened washer is specified, don't replace it with an ordinary commercial flat washer.

7. Confirm finish

Match the finish requirement of the fastening system & service environment.

M8 High Tensile Washers

Looking for an M8 high tensile washer?

Start by confirming that the bolt is actually M8, then check the washer's documented inside diameter, outside diameter, thickness, hardness & finish.

Don't identify an M8 washer from OD alone.

M10 High Tensile Washers

M10 high tensile washers are selected for compatible M10 high-strength fastening assemblies.

Two washers sold for M10 applications can still belong to different washer series or specifications.

Match the complete product requirement rather than nominal diameter alone.

M12 High Tensile Washers

For an M12 high tensile flat washer, check more than whether the bolt passes through the centre.

Ask:

► Is a hardened washer required?
► What OD is specified?
► What thickness is required?
► What finish does the assembly call for?
► Is the bolt Class 8.8, Class 10.9 or another class?

Those questions are more useful than matching appearance.

M16 High Tensile Washers

M16 is common across heavier machinery, fabrication & industrial fastening.

When selecting an M16 hardened washer, check it against the complete M16 bolt & nut arrangement.

If you're replacing existing hardware, don't assume the washer currently fitted is correct simply because the equipment has operated with it.

M20 High Tensile Washers

As fastener diameter increases, incorrect substitution becomes increasingly undesirable.

For M20 high tensile washers, verify the washer dimensions & specification against the connection rather than choosing the largest washer that fits comfortably over the thread.

M24 High Tensile Washers

Large M24 high tensile washers may be used within substantial bolted assemblies.

At this scale, purchasing from a description such as “big hardened washer” isn't enough.

Put the complete specification on the order.

What About Other Metric Sizes?

Metric high tensile washer ranges can extend below M8 & well beyond M24.

The same selection logic applies regardless of diameter.

Metric size first. Washer specification second. Finish third.

If you're measuring unidentified hardware, Calipers (Digital / Manual) can help check physical dimensions, but measurement shouldn't replace a known product specification where one exists.

High Tensile Washers for Class 8.8 Bolts

Class 8.8 bolts are widely used across metric high-strength fastening.

Where the connection requires a hardened washer, choose a washer specified for the assembly.

The fact that a standard washer fits over an M16 Class 8.8 bolt doesn't establish that it has the required properties.

High Tensile Washers for Class 10.9 Bolts

The same principle applies to Class 10.9 high tensile bolts.

Higher bolt strength doesn't mean washer selection becomes less important.

Use the washer required by the joint design, fastener system or equipment specification.

High Tensile Washer vs Standard Flat Washer

From a metre away, they can look almost identical.

That doesn't make them interchangeable.

If the connection calls for a hardened high tensile washer, use one.

High Tensile Washer vs Structural Washer

“High tensile” & “structural” shouldn't automatically be treated as the same product description.

Structural bolting systems can require washers manufactured to particular standards.

Some high tensile washer products in the Australian market comply with structural washer standards, while others are marketed simply as hardened high tensile washers.

If the drawing nominates a washer standard, match that standard specifically.

High Tensile Washer vs Spring Washer

These washers perform different functions.

A high tensile flat washer provides a hardened flat bearing surface where specified.

A spring washer has a different geometry & fastening function.

For assemblies specifically requiring that washer type, browse Spring Washer.

High Tensile Washer vs Large-Diameter Flat Washer

A larger OD doesn't automatically make a washer more suitable for a high-strength joint.

Large flat washers can provide greater bearing area in appropriate applications, but washer hardness, thickness & specification still matter.

Don't replace a hardened washer with a larger general-purpose washer simply because it covers more surface.

Zinc High Tensile Washers

Zinc high tensile washers & zinc plated high tensile washers are common descriptions in the Australian fastener market.

Where the Bremick product selected uses a zinc finish, confirm that finish is appropriate for the complete assembly & environment.

Don't identify a hardened washer purely by its plated appearance.

Plain High Tensile Washers

Plain high tensile washers are also found across high-strength fastening systems.

A plain finish isn't automatically inferior to zinc.

The required finish depends on the specified fastener assembly & operating environment.

Galvanised High Tensile Washers

Galvanised high-strength fastening systems can require compatible washers.

Don't assume a zinc plated, plain & galvanised washer can be exchanged solely because all three fit the same bolt.

Coating thickness, assembly requirements & relevant specifications can matter.

Inside Diameter: The First Physical Check

The washer's internal hole needs to suit the nominated bolt.

But fitting over the thread is only the first check.

A washer can physically fit while still having the wrong:

► OD
► Thickness
► Hardness
► Finish
► Standard

“Fits the bolt” isn't the same as “matches the connection”.

Outside Diameter: Check the Bearing Footprint

OD determines how much area the washer occupies beneath the bolt head or nut.

A bigger OD isn't universally better.

The washer should provide the geometry required by the joint.

Thickness: Don't Judge Strength by Eye

Two metric washers can have similar ID & OD dimensions while differing in thickness.

Likewise, a thick washer isn't automatically a high tensile washer.

Use the documented product specification rather than visual assumptions.

Matching High Tensile Washers With Bolts

The markings on a metric high tensile bolt tell you about the bolt's property class.

They don't identify the washer automatically.

For example:

Class 8.8 bolt + random M16 washer = not enough information

A better purchasing description is:

M16 Class 8.8 bolted assembly + specified hardened washer + compatible nut + required finish

For complete matched bolt & nut requirements, compare Bremick High Tensile Bolt & Nut.

Matching the Nut

Don't stop once the washer is correct.

Nut diameter, thread, property class & finish also need to suit the bolt assembly.

A perfectly selected washer won't correct an incompatible nut.

Should the Washer Go Under the Nut?

Often, but not universally.

Some connections require a washer beneath the nut.

Others can require one beneath the bolt head.

Some assemblies specify washers in both positions.

Follow the connection design rather than applying one universal washer arrangement.

Can You Stack High Tensile Washers?

Don't use a stack of washers as an automatic solution to excessive bolt length.

If the bolt is too long, determine why.

If the fixture has changed, reassess the fastener length.

If the connection specifically permits multiple washers, follow that requirement.

Otherwise, select the correct hardware rather than improvising spacer thickness.

Can High Tensile Washers Be Reused?

Don't assume reuse is acceptable simply because the washer still looks flat.

Inspect removed hardware for:

► Distortion
► Galling
► Corrosion
► Cracking
► Surface damage
► Damaged ID
► Coating deterioration
► Signs of abnormal loading

For specification-controlled joints, follow the applicable inspection & replacement requirements.

Expert Tips

Read the fastener schedule before opening the washer bin. The drawing may specify more than nominal diameter.

Match the bolt size first. Then confirm ID, OD, thickness, hardness & finish.

Keep Class 8.8 & Class 10.9 assembly hardware identified. Don't mix it indiscriminately with general workshop fasteners.

Don't identify hardness by colour. Zinc plating tells you about finish, not the complete mechanical specification.

Separate high tensile flat washers from standard flat washers. Clear storage labels reduce substitution errors.

Don't assume thicker means stronger. Dimensions need to match the washer specification.

Treat structural joints separately. If a structural washer standard is specified, follow it.

Check both sides of the joint. Bolt, nut, washer & connected surfaces all matter.

Don't solve bolt-length problems with a handful of washers. Select the correct fastener length.

Write useful descriptions on purchase orders. “M16 high tensile hardened flat washer, specified finish” is much better than “M16 washer”.

For a broader explanation of matching bolts, nuts, washers & other fastening hardware, read Fastener Guide Bolts Screws Anchors.

Small components deserve the same attention as the tool used to tighten them. Why Good Fasteners Matter More Than the Tool You Drive Them With looks at why fastening hardware shouldn't be treated as an afterthought.

For an industrial maintenance perspective where reliable hardware selection matters during equipment work, read Quarry Crews Crusher Maintenance.