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ISO 6310 Compressive Strain Test for Brake Linings

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ISO 6310 Brake Lining Compressive Strain Tester | UnitedTest

ISO 6310 specifies compressive strain test methods for road vehicle brake linings, measuring compressibility, thermal swell, and heat transfer under ambient and high temperatures. UnitedTest manufactures fully ISO 6310 compliant brake pad testing machines for automotive brake performance validation.


ISO 6310 is an international standardized laboratory testing standard for road vehicle brake linings, establishing unified compressive strain test procedures to evaluate key mechanical and thermal performance parameters of automotive friction materials. The standard comprehensively tests brake lining compressibility, compressive strain, thermal swell, permanent thermal growth, and heat transfer performance under mechanical compression across ambient temperature and extreme high-temperature conditions up to 400°C, perfectly simulating actual vehicle braking operating environments. It defines two professional test methods, Method A and Method B, tailored for diverse brake component specimens, including raw friction material coupons, air brake pads, commercial vehicle brake linings, and complete hydraulic passenger car disc brake pad assemblies, covering full-range automotive brake lining testing scenarios.


This standard is distinctly different from ISO 6313. While ISO 6313 only detects passive heat-induced dimensional deformation under no heavy mechanical load, ISO 6310 focuses on real-world working conditions, testing brake lining thickness deformation under simulated brake caliper compression force paired with thermal exposure. This combined load and heat testing mode delivers more accurate, practical performance data for braking system design, material selection, and quality inspection.


UnitedTest designs and manufactures high-precision ISO 6310 compliant brake lining compressive strain testing machines. Our professional test equipment supports accurate measurement of brake lining compressive strain, thermal deformation and heat transfer properties under variable temperature and compression load, ideal for automotive brake factory quality control, friction material R&D, and third-party laboratory performance certification.


Test Principle

The test simulates the actual compressive load applied by brake caliper pistons during vehicle braking, with parallel room-temperature and high-temperature (400 ±10 °C) testing to capture four key material responses:

Ambient compressibility: Reversible thickness compression of friction material under cyclic hydraulic pressure at normal room temperature;

Hot compressibility: Compressive deflection under combined high temperature and mechanical load, reflecting softening of friction composites under braking heat;

Temperature transfer (TT): Heat conduction through the pad from hot friction surface to steel backing plate, calculated as TT=T3-T2;

Thermal swell (dS) & permanent thermal growth (dG): Temporary thickness expansion at 400 °C and irreversible residual thickness change after cooling back to room temperature post thermal compression cycling.

A uniaxial loading frame applies cyclic compression loads matching real brake hydraulic line pressure, while high-precision displacement sensors record sample deflection. Built-in heating platens replicate sustained high braking temperatures, and embedded thermocouples track temperature gradients across the pad assembly. Machine frame deflection is mathematically subtracted to isolate pure friction material deformation, eliminating equipment measurement error.


Two Official Test Methods (Method A vs Method B)

Method A – Coupon & Commercial Vehicle / Air Brake Pads

Target: Raw friction material lab R&D, heavy-duty commercial vehicle disc/drum linings, air brake assemblies

Loading pressure parameters (contact face pressure on friction surface):

Commercial vehicle disc pad: Max 8 MPa; loading ramp rate 4.0 ±0.5 MPa/s

Commercial vehicle drum lining: Max 5 MPa; ramp rate 2.5 ±0.5 MPa/s

Light drum brake lining: Max 3 MPa; ramp rate 1.5 ±0.5 MPa/s

Loading cycle: 3 full load-unload cycles for room-temperature compressibility test.

Hot test hold time: 15 min ±10 s at maximum test pressure on 400 °C platen.

Method B – Hydraulic Disc Brake Pad Assemblies (Passenger Car / Light Truck)

Target: Complete production disc brake pads for hydraulic caliper brake systems

Simulated hydraulic line pressure (two standard options, clearly documented in report):

Standard low setting: 10 MPa (100 bar); standard high setting: 16 MPa (160 bar)

Loading ramp rate: 8 MPa/s (80 bar/s) simulated line pressure; crosshead speed control at 15 mm/min.

Loading cycle: 3 cycles for ambient test; 2 cycles for hot compressibility test.

Hot test hold time: 10 min ±10 s at max pressure on 400 °C heating plate.


Test Specimen Requirements

Sample typesDisc brake pad assemblies or coupon samples cut from friction material
Minimum quantity (room temperature)5 samples
Minimum quantity (elevated temperature)3 samples
Surface conditionFlatness and roughness must match normal production
Anti-noise shims/rubber coatingsShould be removed for friction material property testing (and reported)
Thickness measurement5-point measurement with micrometer; report average d to 0.1 mm accuracy
Contact area A₀Measure actual friction material area; account for slots, chamfers, holes

For Method A coupon samples, the loading ram face must be flat and at least circumscribe the sample periphery. For commercial vehicle pads, the standard ram is an annular piston with 60 mm outer diameter and 50 mm inner ring diameter.


Test Equipment of ISO 6310 Compressive Strain Test for Brake Linings

Recommend UnitedTest UT1058-CSTE Brake lining compress strain & thermal expansion testing machine, fully meet ISO 6313 and mainly consist of: 

Uniaxial Compression Test Stand / Load Frame

Rigid frame providing uniform vertical compression load over sample contact surface; force measurement accuracy within 1% full scale.

Dual loading ram designs:

Flat full-face ram for Method A coupon samples; annular piston ram (60 mm outer / 50 mm inner diameter) for commercial vehicle pads;

Caliper piston-shaped fixture for Method B full pad assemblies, matching actual vehicle caliper piston geometry for test repeatability.

Heated Test Platen

Electric heating plate capable of stable surface temperature at (400 ±10) °C; minimum 30-minute preheat stabilization before hot testing.

Embedded 1.5 mm diameter thermocouple 3 mm below platen surface (center line of loading ram) to monitor heating plate temperature.

Temperature Monitoring Hardware

Two sets of sheathed thermocouples: one for heating plate, a second inserted into pad backing plate to measure heat transfer TT

Displacement Measuring Devices

High-resolution displacement gauge/inductive transducer with 0.001 mm (1 μm) precision, mounted along ram centerline to track sample thickness deflection.

Automatic data logger/PC recording system to log load, pressure, displacement, temperature vs time continuously.


Key Test Parameters & Mandatory Stipulations

Pre-load baseline: 0.5 MPa (5 bar) contact pressure / hydraulic line pressure, held ≤5 seconds before zeroing displacement gauge.

Hot test temperature: Heating plate stabilized at (400 ±10) °C, preheat minimum 30 minutes to eliminate thermal gradient.

Deflection compensation rule: Machine frame deflection Dapp must be subtracted from total measured deflection Dtot to calculate pure sample net deflection: (D=Dtot-Dapp). Compensation can be automated via software or manual post-processing.

Calibration requirement: Monthly machine verification with standardized reference samples; re-calibrate force, displacement and temperature sensors if reference reading deviation exceeds 5 μm.

Post-hot-test measurement: After hot compression cycles, fully cool sample to ambient temperature then re-measure lining thickness to calculate permanent thermal growth dG.


Test Applications (Industry Fields)

ISO 6310 is widely used by:

Brake component manufacturers — product development, material selection, quality control

Friction material suppliers — R&D of new formulations, benchmarking against competitors

Automotive OEMs — pad characterization, predicting brake pedal travel, assessing judder/noise propensity

Independent test laboratories — certification and comparative testing.


Related Standards: 

ISO 6313

Road vehicles; Brake linings; Effects of heat on dimensions and form of disc brake pads; Test procedure

GB/T 22310

Road vehicles—Brake linings—Effects of heat on dimensions and form of disc brake pads test method

SAE J160Swell, Growth, and Dimensional Stability of Friction Materials and Noise Insulators when Exposed to Elevated Temperatures — referenced by ISO 6313
SAE J2581Thermal Transport Properties Germane to Friction Materials and Brakes — referenced by ISO 6313
ISO 6310

Compressive strain and thermal swell test for brake pads;

measures combined compressibility and thermal dimensional growth under load-temperature cycles, overlapping thermal stability evaluation scope with ISO 6313 but with different rig geometry and test loading logic.

ISO 6312Shear strength of full disc brake pad assemblies (bonds friction material to backing plate; post-ISO 6313 thermal test destructive validation).
ISO 15484Brake lining product quality assurance standard; lists ISO 6313 as a mandatory thermal stability test for friction material qualification reports
JIS D4413Automotive parts -- Brake linings and brake pads -- Compressive strain test method


Keywords: ISO 6310 brake lining compressive strain test, ISO 6310 automotive brake pad tester, road vehicle brake lining compressibility test, brake lining thermal swell permanent thermal growth tester, 400°C high temperature brake friction material test equipment, ISO 6310 Method A Method B brake pad testing machine, hydraulic disc brake pad compressive deformation tester, commercial vehicle air brake lining performance test, brake caliper compression load thermal combined test, automotive friction material heat transfer performance tester

Related products and device

ISO 6310 Brake liningCompressive Strain testing machine

Professional Brake Lining Compress Strain & Thermal Expansion Testing Machine by UnitedTest. Compliant with ISO 6310 & ISO 6313. Measure compressive strain, thermal swell and heat conduction of disc/drum brake pads and friction materials.

Related Standard

ISO 6313 Disc Brake Pad Thermal Heat Resistance Test

ISO 6313 Road vehicles - Brake linings - Effects of heat on dimensions and form of disc brake pads - Test procedure

ISO 6313 specifies a combined test method that simultaneously measures: 1, dimensional changes of a disc brake pad as a function of temperature, 2, the pad's resistance to heat transfer in the direction of the applied pressure. 


FAQ: ISO 6310 Brake Lining Compressive Strain Test

UnitedTest — ISO 6310:2009 Compliant Brake Lining Compressive Strain Test Machines


UnitedTest is a leading manufacturer of ISO 6310:2009-compliant brake lining compressive strain test equipment, engineered for friction material manufacturers, automotive OEM braking divisions, and independent testing laboratories worldwide. Our ISO 6310 test machines deliver precise, repeatable measurement of compressive displacement, thermal swell, thermal growth, and temperature transfer — helping you characterize friction materials faster, reduce warranty risk, and meet global automotive safety standards.


Q1. What is the ISO 6310 test?

A: ISO 6310 is an international standard prepared by ISO/TC 22/SC 33 that specifies laboratory test methods to measure the compressive displacement of brake linings or brake pad assemblies caused by mechanical loading and temperature. It also provides a method to assess lining thermal swell and growth at elevated temperatures. 


Q2. Why is ISO 6310 testing important?

A: The compressive response of a brake lining is a fundamental design parameter that directly influences:

Brake fluid displacement during a brake application

Brake pedal travel and overall pedal feel

The propensity of the brake to generate judder or noise

Brake pad characterization for quality control and material selection

If a friction material compresses too much, the pedal travel becomes excessive; if it compresses too little, the initial bite may be too aggressive. By quantifying compressibility at both ambient and 400°C, ISO 6310 helps manufacturers predict real-world braking behaviour before costly dynamometer or vehicle tests. It is also indispensable for screening formulations that might contribute to noise, judder, or thermal degradation.


Q3: What is the core difference between ISO 6310 and ISO 6313?

A: ISO 6310: Measures thickness deformation under simulated brake hydraulic compression load + high temperature, evaluating mechanical compressibility, heat transfer and permanent thermal growth under working braking pressure.

ISO 6313: Measures passive heat-induced dimensional deformation under only light clamping pressure, without heavy caliper compression force.

Data from the two standards cannot substitute each other; brake manufacturers typically run both tests for full thermal-mechanical material characterization.


Q4: Can I test brake pads with anti-noise shims intact?

A4: Yes, but two requirements apply:

Record the presence of shims clearly in the final test report.

If testing pure friction material performance only, remove shims as shims will alter compressibility and heat transfer results and skew material property data.


Q5: Does UnitedTest manufacture fully ISO 6310 compliant compressibility test machines?

A5: Yes. UnitedTest is a professional global manufacturer of ISO 6310 brake lining compressive strain test rigs. Our machines fully comply with all clauses of ISO 6310:2009, supporting both Test Method A and Test Method B in one unit, with integrated heating platens, multi-channel temperature monitoring, automatic cycle control and built-in ISO-standard report generation software.


Q6: What unique advantages does UnitedTest’s ISO 6310 test machine have?

A6: Dual-mode automatic switching: Supports Method A (coupon/CV linings) and Method B (passenger car pads) without manual fixture replacement.

Precise 400 °C heating platen with ±2 °C temperature stability, auto 30 min preheat countdown function.

Built-in automatic deflection compensation function to subtract machine frame deflection \(D_{app}\) and output pure sample net deflection D directly.

1 μm high-resolution inductive displacement transducers for ultra-precise thermal swell and growth measurement.

Custom piston fixture options (annular, single solid, multi-piston adapters) matching all mainstream vehicle caliper designs.

Automated test cycle execution: 3 ambient compression cycles, 2 hot compression cycles, auto hold timer (10 min car pad /15 min CV lining).

One-click standardized test report export fully aligned with ISO 6310 Annex A template, including compressibility, hot compressibility, temperature transfer and permanent thermal growth data.

Global after-sales service: remote operation training, annual force/temperature/displacement calibration, spare parts supply and software upgrade support.


Q7. What is the test procedure?

Step 1 — General Setup

Calibrate the test stand. Measure sample thickness at 5 points, calculate average d. For disc brake pads, subtract backing plate thickness to get friction material thickness only. Measure and record contact area A₀. Place the sample on the platen with the friction surface against the platen, ensuring piston fixture location matches the actual application.

Step 2 — Room Temperature Compressibility Test

Apply pre-load of 0.5 MPa for ≤5 s, zero the displacement gauge, then perform three loading/unloading cycles from pre-load to maximum pressure at the specified ramp rate. Record displacement at maximum pressure on the first and last cycles.

Step 3 — Temperature Transfer & Thermal Expansion

Install thermocouple in the pad backing plate (centre of piston area). Preheat platen to (400 ± 10)°C and stabilize for ≥30 min. Place the ambient sample on the heated platen, record initial backing plate temperature T₂, apply pre-load. After 10 min (PC) or 15 min (CV), record final backing plate temperature T₃ and change in pad thickness (thermal swell dS). Temperature transfer TT = T₃ − T₂.

Step 4 — Hot Compressibility Test

Reset displacement gauge to zero. Perform two compression cycles using the same parameters as the room temperature test. Remove the sample and allow to cool to ambient temperature. Re-measure pad thickness and calculate pad thermal growth dG (permanent thickness change).

Step 5 — Apparatus Deflection Compensation

Subtract apparatus deflection Dapp (measured by loading the ram against the base platen without a sample) from total measured deflection to obtain net sample deflection D = Dtot − Dapp. This can be done automatically or manually.

Step 6 — Test Report

Report must include manufacturer and reference details, sample type, coatings/shims, sample area, number of samples, assembly and friction material thickness, piston size, test method used (A or B), average ambient and hot compressibility/strain values, and environmental conditions.


Q8: Why Choose UnitedTest as Your ISO 6310 Test Machine Manufacturer?

A: As a specialized supplier of full-series automotive friction material testing equipment, UnitedTest independently develops and produces ISO 6310 compressibility test machines fully aligned with ISO 6310:2009 international standard requirements, serving global brake lining manufacturers, automotive OEM laboratories and third-party vehicle safety certification institutions.

Our ISO 6310 compressive strain test rig is designed to replicate the combined mechanical compression and high-temperature thermal load that brake pads experience during real vehicle braking, quantifying five key performance indicators of friction materials: ambient compressibility, hot compressibility at 400°C, heat transfer through pad assemblies, temporary thermal swell and permanent thermal growth after heat cycling.

Factory direct supply: Independent R&D and production workshop, competitive factory price without intermediate dealers, flexible MOQ for lab and batch orders.

Customization service: Custom heating temperature range, special piston fixture adapters, single/dual sample stations and customized test report formats for unique vehicle brand requirements.

Strict quality calibration: Every machine undergoes full force, temperature and displacement calibration before delivery, supplied with calibration certificates matching ISO standard verification rules.

Global full after-sales support: Overseas remote installation guidance, operator training videos, annual precision calibration service, long-term spare parts supply and free software upgrade to align with updated ISO brake lining standards.

One-stop friction testing solution: UnitedTest provides a complete portfolio of ISO brake lining test machines (ISO 6310, ISO 6313, ISO 6312, ISO 6311) to meet all friction material performance testing demands in one purchase.


Q9: Who Uses UnitedTest ISO 6310 Test Machines?

A: Brake pad & lining manufacturers qualifying new friction formulations for passenger cars, light trucks, and commercial vehicles

Automotive OEM braking system divisions characterizing pad behaviour for pedal travel prediction

Independent test labs offering ISO 6310 certification and benchmarking services

Friction material R&D centres investigating compressive response, thermal swell, and heat transfer

Commercial vehicle braking suppliers qualifying heavy-duty drum and disc brake linings

Brake noise & judder research teams screening formulations for NVH propensity

Quality control departments performing incoming and outgoing inspection of brake pad stock.

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