Committee on Steel Approves New Practice for Portable Hardness Testing
Most standard hardness tests for steel, including the Brinell, Vickers and various Rockwell tests, are generally classified as bench testers. This means that the component being tested needs to be taken to the machine for hardness to be determined. In order to test larger pieces, such as forgings, a section would need to be removed from the forging in order for it to be tested. Since this is not always feasible or even possible, ASTM International Committee A01 on Steel, Stainless Steel and Related Alloys has developed a standard for portable hardness testing. The new standard, A 1038, Practice for Portable Hardness Testing by the Ultrasonic Contact Impedance Method, is under the jurisdiction of Subcommittee A01.06 on Steel Forgings and Billets.
The solution is to take the hardness tester to the forging rather than the other way around, says Ed Nisbett, an independent consultant who is chairman of Subcommittee A01.06. This requires the use of portable equipment, and a user must be assured that the test results are accurate and reflect the requirement of the material product specification.
According to Nisbett, A 1038 fills a very real void in the steel industry. The equipment covered by this practice is not new; it has been available internationally for years, says Nisbett. However, use of the equipment has been hampered by the lack of a consensus standard.
A major application of A 1038 will be in the hardness testing of finished components, such as gear forgings and crankshafts, as well as for hardened surfaces. The need is to show that the required hardness has been achieved in the finished part, while not damaging the component in the process, says Nisbett. This is particularly the case when the hardened surface layer is thin.
Nisbett says all interested parties are invited to participate in ongoing revisions of A 1038.
Ed Nisbett, independent consultant, Navarre, Fla.
ASTM staff: George Luciw
Upcoming Meeting: May 16-19,
May Committee Week, Reno, Nev.