The David L. Ellis Co., Inc. is getting a lot of calls about Ultrasonic Hardness Testers. The problem is "How do you calibrate the tester?" The answer is "Special Material" Blocks. We can help you. Give us a call.
If you have a "Leebs" tester we can calibrate it for you. We recommend you have dual calibration on the blocks. Example: If you use HRC, get the block calibrated to HRC NIST and LD. If it is another scale (HRB Vickers, etc.) we can do dual calibration.
If you use Leebs, the standard blocks that come with the tester is HRC 58. If the tester is used to check HRC 25, HRBW AL, etc., you should get a block close to what you are testing. We have LD & LG blocks from HBW AL to HRC 58.
Industry News
Acton, MA
Direct Verification of Hardness Testers and Documentation
By now some of you have heard rumors about testers failing direct verification and are not allowed to be used for qualifying parts or test items. This requirement can be found in ASTM E18-17e1 appendix A1. Please look at Table A1.1. It states that new testers must have direct verification. The basic issue is that old testers may not have ever had direct verification even when new, or there are no documents to prove it was ever done.
As a result now some accreditation bodies may require this direct information. If it cannot be shown, then direct verification can be attempted. At issue is whether the old tester meets ASTM E18-17e1 appendix A1. It is a near 100% certainty that the old testers will fail. Usually the forces and depth measurements are incorrect. In addition, it is virtually impossible to control the dwell times of the testing cycle as they are controlled by individuals.
Having said all that, it is an option to have the tester directly verified. It is a time consuming and an expensive undertaking. If it still fails, which it probably will, you will have spent a significant amount of money and still need to buy another tester that meets ASTM E18-17e1 appendix A1. This requirement has existed since 2007, but it has not been enforced by auditors until recently.
— Robert Ellis, Quality Manager
Acton, MA
Hardness — An Overview
Hardness testing of metals, composites and minerals is the resistance to indentation, introduced by diamond or tungsten ball, and it is determined by measuring the permanent depth of the indentation. The hardness test is a fast and cost effective method for determining the condition of a material following heat treatment, ease of machining, or to provide insight into strength and wear resistance.
Rockwell, Brinell and Vickers/Knoop hardness testing is the most widely used method for determining the hardness of a material. Generally, the surface should be flat and sanded smooth to obtain an average of three of more readings.
The Brinell Hardness Test is utilized to measure hardness over a larger sample areas. Brinell hardness is particularly useful for castings and forgings that have a rough surface or micro structure too coarse for other hardness testing methods. The most common test in the USA is the Rockwell HRC for hard steel and HRBW for soft alloys.
Brinell testing is often performed with a high test load (500 to 3000 kg most common in the USA) and a 10mm size indenter so the resulting indentation averages out most surface and sub-surface inconsistencies. The resulting impression is measured across at least two diameters and results averaged. The averaged diameter measurement is then converted to a Brinell hardness number.
— David L. Ellis Co., Inc.
Is hardness important in everyday life?
Yes, it is.
If you want to know how and why, rent and see CSI "Chasing The Bus" (Season 2, Episode 18, 2002). Sometimes hardness is a life or death situation!
Product Sales Specials
David L. Ellis Co., Inc. is offering the following product specials at deal pricing while supplies last:
4" × 4" × 3/4" Brinell Blocks
Now at same price as the 6" × 2 × 3/4" Blocks with dual certificates (ASTM & ISO). Call for hardness range and availability.
New 6" × 4½" × 3/4" Blocks
Available at special price. Grids and circle patterns available while supplies last.
