Factors That Influence Almen Strip Arc Height

Author:  P. Bailey and J. Champaigne
Source:  Conf Proc: ICSP-9 (pg 392-399)
Doc ID:  2005115
Year of Publication:  2005
Abstract:  
ABSTRACT Almen strips, developed in the 1940s, are standardized steel coupons whose curvature is used to determine intensity, the impact energy level of a shot stream. Proper application of this system depends on a number of factors related to the strip itself, its mounting block and its use techniques. Specifications contain Almen strip and Almen block dimensional and hardness tolerances. Tests were conducted to determine which of these tolerances significantly affect arc height measurement accuracy. Of factors related to Almen strip use, the use of prebow compensation is shown to be significant. Another factor evaluated was the area of strip coverage. Peening only a central portion of the strip to accommodate small blast pattern peening of small parts was shown in some cases to be an accurate representation of the process. Another study evaluated blocks with different hold down screw placement for potential application to processes in which interference with the screws is an issue. The area factor also relates to measuring intensity of and to applications requiring "shaded strip" determination of intensity in small holes or small slots.