Hardness Testing Services

Rockwell & Superficial

Rockwell and Superficial hardness testing shall be performed in accordance with the latest revision of ASTM E18. 

There are two general classifications of the Rockwell test: the Rockwell hardness and the Rockwell superficial hardness test.  In the Rockwell hardness test, the preliminary test force is 10 kgf. Total test forces are 60 kgf, 100 kgf, and 150 kgf. In the Rockwell superficial hardness test, the preliminary test force is 3 kgf and total test forces are 15 kgf, 30 kgf, 45 kgf. The indenter of either test shall be of spheroconical or spherical configuration The standard indenters are the diamond spheroconical and tungsten carbide ball indenters' 1/16, 1/8, 1/4, 1/2 inch in diameter. CMS can report hardness in the following value scales:

  • Rockwell Scales: A, B, C, D, E, and F

  • Superficial Scales: 15N, 30N, 45N, 15T, 30T, and 45T

   After testing the final report will include Rockwell hardness number, scale used, and readings to nearest the whole number by rounding in accordance with ASTM E29.

Vickers Macro Hardness

This type of hardness is very useful for doing weld profiles and determination of hardness in Heat Affected Zones (HAZ). There are several specifications which call out the use of this type of hardness method. The testing method which governs the macro hardness Vickers is ASTM-E-92.

Other specifications which reference the use of Vickers hardness testing are:

  • API 5L

  • ASME Section IX

  • AWS D1.1

  • NACE MRO175

  • ISO 15156-2

Brinell Hardness Testing

Brinell hardness (HB) testing shall be performed in accordance with the latest revision of ASTM E10.

 

Brinell testing is done with the calibrated Brinell machine that applies a predetermined indenting load to a ball in contact with the specimen. The ball is a 10 mm tungsten carbide ball used to apply load of 3000 or 500 kg, depending on the material for 15 seconds. After the load is applied, the indentation on the surface is measured with a scope which measures in millimeters. The dimension of the indentation and the load used is the calculated to give the Brinell Hardness value of the metal. 

Microhardness Testing Knoop

Microhardness testing shall be performed in accordance with ASTM E384 and ASTM E92 unless otherwise specified by the client.

 

Knoop (HK) and Vickers (HV).

Questions: What would I use Microhardness testing for?

Answer: Microhardness testing gives the advantage of testing materials hardness on very thin layers or sheets. It also allows the measurement of case hardness and the depths of the case. It can also be used to determine decarburization depth or verify that limits were not exceeded during the heat treatment process.

CMS uses both Vickers and Knoop for microhardness from 10 gf to 10 Kgf load evaluation. Both Vickers and Knoop values can then be converted to Rockwell, Brinell, or any other desired scale requested. Please remember that some scales may fall out of conversion requested.

Leeb Rebound Hardness

Leeb rebound hardness testing is a hardness testing technique used for field testing or large components that are not readily available for laboratory testing. This type of testing is done following the latest revision of ASTM A956. This hardness testing can be done with minimal indentation remaining on the surface after testing is performed. It can test a variety of base metals, and the hardness can be converted into known hardness scales. 

Wilson hardness conversion chart is a great reference in determining what hardness you currently have to an approximate value in a different scale.