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Hardness

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Get in touch
“We have been working with you since more than 10 years. During this period your quality & delivery performance found is very good. Even when we arranged a supplier meet in 2012 we awarded you as a best supplier of the year in Bought out item category. Whenever we had any new developments your support was perfect. Overall your performance was very good & we hope the same in future too, We wish you all the best for your business growth.”
Sidel India Pvt. Ltd.
“We are working with Harkesh Rubber since 3 years. Our initial development of few seals for one of the important project developed and supplied by them as per the schedule. We found the quality and commitment for overall business is good. The response and technical support for our need is fair and on-time. Overall the services and co-operation found to be satisfactory. We wish the young and energetic Harkesh Rubber team a very best in all the future endeavours.”
Festo India Pvt Ltd.
“Harkesh Rubber Industries has been our co-partner for the supply of the rubber and its allied products from past 2 years which we used in our daily final product made for Indian Railways. We find the quality of product supplied by them in superior quality which lowest lead time. Overall the services and cooperation found out to be satisfactory in all key areas.”
Crompton Greaves Limited
“Harkesh Rubber Industries has been our co-partner for the supply of the rubber and its allied products from past 2 years which we used in our daily final product made for Indian Railways. We find the quality of product supplied by them in superior quality which lowest lead time. Overall the services and cooperation found out to be satisfactory in all key areas.”
Crompton Greaves Limited
“In all honesty I have to say that for us it's really a pleasure to do business with you now already more than 5 years. In the whole time you had never let us down, your delivery performance is nearly perfect, the service which we get is quicker than quick. The product quality has been never a problem and when we had an issue you help us always to solve it. This reliability is where we trust in and what makes our decision to work with you also in the future very easy.”
ARCA Regler GMBH
“Dear Harkesh Rubber Team, We have been working with you since last 6 years. During this period your Quality, Delivery and Performance found very good and consistent. During the development of new products specially FKM/FPM gaskets, we had very good technical support by your team, and we hope in future it will remain same. We wish you all the best for your business growth. Thanking you,”
Georg Fischer Piping Systems Pvt. Ltd.

Hardness (DH)

The Hardness (DH) of an elastomer is the quantification of its resistance to perpetual indentation. A durometer is commonly used for testing rubber samples. It consists of 12 scales that can be used to specify the hardness of the following rubber samples:

Type Examples of Materials Durometer Hardness
A Natural rubber, thermoplastic elastomers, and soft vulcanized rubber. 20-90 A
B Moderately hard rubber and thermoplastic elastomers. Above 90 A and Below 20 D
C Medium-hard rubber and thermoplastic elastomers. Above 90 B and Below 20 D
D Hard rubber and thermoplastic elastomers. Above 90 A
DO Moderately hard rubber and thermoplastic elastomers. Above 90 C and Below 20 D
M Thin rubber and thermoplastic elastomers. 20-85 A
O Soft rubber and thermoplastic elastomers. Below 20 DO
OO Extremely soft rubber and thermoplastic elastomer. Below 20 O

Hardness Measurement

The durometer can measure the depth of an indentation in the sample. The measurement is achieved by applying force on a presser foot. The depth depends on the:

  • The shape of the presser foot
  • Duration of the test
  • The hardness of the sample
  • The viscoelastic properties of the sample

ASTM D2240 durometers can measure the original or indentation hardness over a certain period of time. The test requires constant force, without shock, and measuring the depth of the indentation. For a timed hardness, the force needs to be applied for a specific period, before taking the measurement.

The hardness of a sample can be determined by using one of twelve durometer scales. The test is based on the penetration of a certain type of indentor. The indentation hardness is inversely proportional to the penetration and depends on the viscoelastic behavior and the elastic modulus of the sample.

Note that the:

  • Applied force and the geometry of the indentor can influence the measurement. The test method is intended mainly for control purposes.
  • The calculated indentation hardness is not related to the fundamental property of the sample tested.

ASTM D2240 Hardness & Elastic Modulus
Measuring the DH of a sample can be achieved using the following specific formula:
Where,
SA – Type A hardness
SD – Type D hardness
E – Young’s modulus

Hardness (DH)

The Hardness (DH) of an elastomer is the quantification of its resistance to perpetual indentation. A durometer is commonly used for testing rubber samples. It consists of 12 scales that can be used to specify the hardness of the following rubber samples:

Type Examples of Materials Durometer Hardness
A Natural rubber, thermoplastic elastomers, and soft vulcanized rubber. 20-90 A
B Moderately hard rubber and thermoplastic elastomers. Above 90 A and Below 20 D
C Medium-hard rubber and thermoplastic elastomers. Above 90 B and Below 20 D
D Hard rubber and thermoplastic elastomers. Above 90 A
DO Moderately hard rubber and thermoplastic elastomers. Above 90 C and Below 20 D
M Thin rubber and thermoplastic elastomers. 20-85 A
O Soft rubber and thermoplastic elastomers. Below 20 DO
OO Extremely soft rubber and thermoplastic elastomer. Below 20 O

Hardness Measurement

The durometer can measure the depth of an indentation in the sample. The measurement is achieved by applying force on a presser foot. The depth depends on the:

  • The shape of the presser foot
  • Duration of the test
  • The hardness of the sample
  • The viscoelastic properties of the sample

ASTM D2240 durometers can measure the original or indentation hardness over a certain period of time. The test requires constant force, without shock, and measuring the depth of the indentation. For a timed hardness, the force needs to be applied for a specific period, before taking the measurement.

The hardness of a sample can be determined by using one of twelve durometer scales. The test is based on the penetration of a certain type of indentor. The indentation hardness is inversely proportional to the penetration and depends on the viscoelastic behavior and the elastic modulus of the sample.

Note that the:

  • Applied force and the geometry of the indentor can influence the measurement. The test method is intended mainly for control purposes.
  • The calculated indentation hardness is not related to the fundamental property of the sample tested.

ASTM D2240 Hardness & Elastic Modulus
Measuring the DH of a sample can be achieved using the following specific formula:
Where,
SA – Type A hardness
SD – Type D hardness
E – Young’s modulus

NEED HELP?

Speak with a human to filling out a form? call corporate office and we will connect you with a team member who can help.

Get in touch
“We have been working with you since more than 10 years. During this period your quality & delivery performance found is very good. Even when we arranged a supplier meet in 2012 we awarded you as a best supplier of the year in Bought out item category. Whenever we had any new developments your support was perfect. Overall your performance was very good & we hope the same in future too, We wish you all the best for your business growth.”
Sidel India Pvt. Ltd.
“We are working with Harkesh Rubber since 3 years. Our initial development of few seals for one of the important project developed and supplied by them as per the schedule. We found the quality and commitment for overall business is good. The response and technical support for our need is fair and on-time. Overall the services and co-operation found to be satisfactory. We wish the young and energetic Harkesh Rubber team a very best in all the future endeavours.”
Festo India Pvt Ltd.
“Harkesh Rubber Industries has been our co-partner for the supply of the rubber and its allied products from past 2 years which we used in our daily final product made for Indian Railways. We find the quality of product supplied by them in superior quality which lowest lead time. Overall the services and cooperation found out to be satisfactory in all key areas.”
Crompton Greaves Limited
“Harkesh Rubber Industries has been our co-partner for the supply of the rubber and its allied products from past 2 years which we used in our daily final product made for Indian Railways. We find the quality of product supplied by them in superior quality which lowest lead time. Overall the services and cooperation found out to be satisfactory in all key areas.”
Crompton Greaves Limited
“In all honesty I have to say that for us it's really a pleasure to do business with you now already more than 5 years. In the whole time you had never let us down, your delivery performance is nearly perfect, the service which we get is quicker than quick. The product quality has been never a problem and when we had an issue you help us always to solve it. This reliability is where we trust in and what makes our decision to work with you also in the future very easy.”
ARCA Regler GMBH
“Dear Harkesh Rubber Team, We have been working with you since last 6 years. During this period your Quality, Delivery and Performance found very good and consistent. During the development of new products specially FKM/FPM gaskets, we had very good technical support by your team, and we hope in future it will remain same. We wish you all the best for your business growth. Thanking you,”
Georg Fischer Piping Systems Pvt. Ltd.
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