Reading Brinell Impressions
The first thing to consider when choosing a Brinell reading device is: how accurate a Brinell Reading you need and then consider if you want to read the impression manually or automatically? Is a reading to the nearest tenth of a mm sufficient or do you need greater accuracy in your readings?
Manual reading is easy and straightforward. You look through the lenses, focus the optics, position in the lens on the impression and read the result in mm. The result in mm is then converted to HBW (Hardness Brinell) by looking up the mm measurement and the table provides the hardness.
Automatic reading uses a digital camera which shoot the image and does the calculations for you and tells you the diameter of the impression in mm and also the HBW (Hardness Brinell) number. Automatic readers reduce the opportunity for human error and provide greater precision in the readings with readings measured to the .01mm. They also eliminate the need for the Brinell table lookup because the automatic reader does the calculation for you and provides you the Brinell hardness level.
Manual is easier and less expensive up front. However, the other consideration is the potential for human error and the reproduce-ability of results. The human eye and interpretation play a much larger role in handheld results than in automatic results and the time savings may justify the purchase of an automated reading device. Additional considerations come from the ASTM E10 specification which defines two types of devices; type A and type B.
ASTM E10 Considerations
The measurement device used for the measurement of the diameter of Brinell indentations may be an integral part of the hardness machine or a separate stand-alone instrument. The allowable measurement devices are classified into two types.
The Type A device includes microscopes having movable measuring lines with some type of indicator or computerized measuring system, or an image analysis system.
The Type B device is a hand-held microscope with fixed measuring lines. Type B devices shall not be used for measuring indentations made with 2.5 mm and 1 mm ball indenters.
Note the limitations on the use of handheld scopes as it pertains to smaller indentations.
King Tester Readers
King offers both handheld and automatic reading systems. We have two Type A devices; the KingScan which is computerized and fully automatic and the KingScope 100 which is handheld. For Type B handheld we offer the KingScope which has been and continues to be the industry preference for a handheld reader.