OK
The material selection platform
Plastics & Elastomers
The material selection platform
Plastics & Elastomers

Hardness Rockwell M

What is Rockwell Hardness?


Rockwell Hardness test is one possible method to measure the Hardness of Plastics. It is generally used for hard materials, like PA, PC, PS, or POM, where the resilience or creep of the polymer is less likely to affect results.

For rubbers, elastomers & softer plastics, Shore Hardness is often preferred.


How Does Rockwell Hardness Test Work?


The Rockwell Scale determines the hardness by measuring the depth of penetration of an indenter under a large load compared to the indentation made by a pre-load.  There are different scales, denoted by a single letter, that use different loads or indenters. The result is a dimensionless number. Indenters can be diamond tips, steel or Tungsten Carbide balls.

The Rockwell testing procedures used in the Plastic Industry are ASTM D785 and ISO2039-2.



The three most common scales used for plastics are Rockwell E, Rockwell M, and Rockwell R.


Rockwell Hardness Testing Conditions


As the method is extended from metals to plastics, one has to be careful to consider:

  • The effects of temperature: Small changes in temperature can result in first and second order phase transitions which can radically alter the hardness of the material.
  • The effects of viscoelasticity:  Unlike metals, plastics are viscoelastic. The stress-strain relationships are time dependent. The results obtained by dragging the weighted indenter will be rate dependent.


Typical Hardness Rockwell M Values


Click to find polymer you are looking for:
A-C     |      E-M     |      PA-PC     |      PE-PL     |      PM-PP     |      PS-X

Polymer Name Min Value Max Value
ABS Flame Retardant
20.00 70.00
ABS High Heat 20.00 50.00
ABS High Impact 10.00 30.00
ABS/PC Blend - Acrylonitrile Butadiene Styrene/Polycarbonate Blend
50.00 70.00
ABS/PC Blend 20% Glass Fiber 50.00 80.00
ABS/PC Flame Retardant
50.00 80.00
Amorphous TPI Blend, Ultra-high heat, Chemical Resistant (Standard Flow) 112.00 112.00
ASA - Acrylonitrile Styrene Acrylate
10.00 20.0
ASA/PC Blend - Acrylonitrile Styrene Acrylate/Polycarbonate Blend
30.00 60.00
ASA/PC Flame Retardant 30.00 70.00
ASA/PVC Blend - Acrylonitrile Styrene Acrylate/Polyvinyl Chloride Blend 30.00 70.00
CA - Cellulose Acetate
1.00 80.00
CAB - Cellulose Acetate Butyrate
1.00 70.00
CP - Cellulose Proprionate 1.00 75.00
CPVC - Chlorinated Polyvinyl Chloride
40.00 65.00
ETFE - Ethylene Tetrafluoroethylene
1.00 10.00
EVA - Ethylene Vinyl Acetate
1.00 1.00
EVOH - Ethylene Vinyl Alcohol
85.00 104.00
FEP - Fluorinated Ethylene Propylene
1.00 1.00
HDPE - High Density Polyethylene
1.00 1.00
HIPS - High Impact Polystyrene
1.00 1.00
HIPS Flame Retardant V0 1.00 1.00
Ionomer (Ethylene-Methyl Acrylate Copolymer)
1.00 1.00
LCP - Liquid Crystal Polymer
40.00 76.0
LCP Carbon Fiber-reinforced 99.00 99.0
LCP Glass Fiber-reinforced 77.00 87.0
LCP Mineral-filled 63.00 79.0
LDPE - Low Density Polyethylene
1.00 1.00
LLDPE - Linear Low Density Polyethylene
1.00 1.00
PA 11 - (Polyamide 11) 30% Glass fiber reinforced
116.00 116.00
PA 11, Rigid 1.00 25.00
PA 12 (Polyamide 12), Glass Filled 107.00 107.00
PA 46 - Polyamide 46
92.00 92.00
PA 6 - Polyamide 6
30.00 80.00
PA 6-10 - Polyamide 6-10
1.00 50.00
PA 66 - Polyamide 6-6
30.00 80.00
PA 66, 30% Glass Fiber 30.00 80.00
PA 66, 30% Mineral filled 30.00 80.00
PA 66, Impact Modified, 15-30% Glass Fiber 66.00 96.00
PA 66, Impact Modified
50.00 94.00
PAI - Polyamide-Imide
105.00 120.00
PAI, 30% Glass Fiber 95.00 110.00
PAI, Low Friction 95.00 110.00
PAN - Polyacrylonitrile 45.00 78.00
PARA (Polyarylamide), 30-60% glass fiber
110.00 110.00
PBT - Polybutylene Terephthalate
70.00 90.00
PBT, 30% Glass Fiber 90.00 95.00
PC (Polycarbonate) 20-40% Glass Fiber 70.00 95.00
PC (Polycarbonate) 20-40% Glass Fiber Flame Retardant 70.00 95.00
PC - Polycarbonate, high heat
70.00 90.00
PCTFE - Polymonochlorotrifluoroethylene
10.00 40
PE - Polyethylene 30% Glass Fiber
1.00 20.00
PEEK - Polyetheretherketone
55.00 100.00
PEEK 30% Carbon Fiber-reinforced 70.00 107.00
PEEK 30% Glass Fiber-reinforced 70.00 103.00
PEI - Polyetherimide
100.00 110.00
PEI, 30% Glass Fiber-reinforced 90.00 125.00
PEI, Mineral Filled
90.00 120.00
PESU - Polyethersulfone
85.00 88.00
PESU 10-30% glass fiber 90.00 99.00
PET - Polyethylene Terephthalate
50.00 100.00
PET, 30% Glass Fiber-reinforced 70.00 95.00
PET, 30/35% Glass Fiber-reinforced, Impact Modified 62.00 62.00
PE-UHMW
1.00 1.00
PFA - Perfluoroalkoxy
1.00 1.00
PI - Polyimide
110.00 110.00
PMMA - Polymethylmethacrylate/Acrylic
70.00 105.00
PMMA (Acrylic) High Heat 90.00 100.00
PMMA (Acrylic) Impact Modified 35.00 80.00
PMP - Polymethylpentene
100.00 100.00
PMP 30% Glass Fiber-reinforced 1.00 20.00
PMP Mineral Filled 1.00 20.00
POM - Polyoxymethylene (Acetal)
75.00 94.00
POM (Acetal) Impact Modified
35.00 79.00
POM (Acetal) Low Friction 58.00 94.00
POM (Acetal) Mineral Filled
83.00 90.00
PP - Polypropylene 10-20% Glass Fiber
20.00 50.00
PP, 10-40% Mineral Filled 1.00 20.00
PP, 10-40% Talc Filled 10.00 45.00
PP, 30-40% Glass Fiber-reinforced 40.00 50.00
PP (Polypropylene) Copolymer
1.00 20.00
PP (Polypropylene) Homopolymer
1.00 30.00
PP, Impact Modified
1.00 1.00
PPA - Polyphthalamide, 33% Glass Fiber-reinforced
124.00 126.00
PPA, 45% Glass Fiber-reinforced 124.00 126.00
PPE - Polyphenylene Ether
50.00 70.00
PPE, 30% Glass Fiber-reinforced 50.00 70.00
PPE, Flame Retardant 50.00 70.00
PPE, Impact Modified 50.00 70.00
PPE, Mineral Filled 60.00 70.00
PPS - Polyphenylene Sulfide 70.00 85.00
PPS, 20-30% Glass fiber 80.00 103.00
PPS, 40% Glass fiber 100.00 104.00
PPS, conductive 70.00 100.00
PPS, Glass fiber & mineral 66.00 102.00
PPSU - Polyphenylene Sulfone
80.00 80.00
PS (Polystyrene) 30% glass fiber 80.00 91.00
PS (Polystyrene) Crystal 60.00 75.00
PS, High Heat 75.00 85.00
PSU - Polysulfone
69.00 91.00
PSU, 30% Glass fiber-reinforced 87.00 100.00
PSU Mineral Filled 70.00 74.00
PTFE - Polytetrafluoroethylene
1.00 1.00
PTFE, 25% Glass Fiber-reinforced 1.00 1.00
PVC (Polyvinyl Chloride), 20% Glass Fiber-reinforced             
50.00 70.00
PVC, Plasticized
1.00 1.00
PVC, Plasticized Filled 1.00 1.00
PVC Rigid
1.00 70.00
PVDC - Polyvinylidene Chloride
60.00 65.00
PVDF - Polyvinylidene Fluoride
75.00 75.00
SAN - Styrene Acrylonitrile
10.00 80.00
SAN, 20% Glass Fiber-reinforced 80.00 100.00
SMA - Styrene Maleic Anhydride
30.00 40.00
SMA, 20% Glass Fiber-reinforced 30.00 40.00
SMA, Flame Retardant V0 30.00 40.00
SMMA - Styrene Methyl Methacrylate
65.00 75.00
XLPE - Crosslinked Polyethylene
1.00 20.00

Also read:


Disclaimer: all data and information obtained via the Polymer Selector including but not limited to material suitability, material properties, performances, characteristics and cost are given for information purpose only. Although the data and information contained in the Polymer Selector are believed to be accurate and correspond to the best of our knowledge, they are provided without implied warranty of any kind. Data and information contained in the Polymer Selector are intended for guidance in a polymer selection process and should not be considered as binding specifications. The determination of the suitability of this information for any particular use is solely the responsibility of the user. Before working with any material, users should contact material suppliers in order to receive specific, complete and detailed information about the material they are considering. Part of the data and information contained in the Polymer Selector are genericised based on commercial literature provided by polymer suppliers and other parts are coming from assessments of our experts.

Copyright SpecialChem SA
Back to Top