Comparing with conventional mechanical shot peening SP technique, water cavitation peening WCP experiments of Almen strips were carried out on a self-manufactured equipment. The results show that WCP demonstrates a wide range of standoff distance SD that from the nozzle to the surface of the object. By measuring the colour changes of the Fuji pressure sensing film, over MPa impacting pressure was detected, which is resulted from the bubbles blasting on the sample surface when the SD is from 65 to mm under 40 MPa of operating pressure. The highest residual stress appears in the top surface layer, while in case of SP it appears in the subsurface.
Electronics Inc. EI can provide strips to any specification, from standard MIL to rigid aerospace specifications. These features add value to a quality shot peening process. They differ in their thickness but have the same width and length. The type of strip is usually specified by the part designer. Grade 3 strips are economically priced and bulk packaged. Excess oil is removed from the Grade 2 Standard strips.
Advanced Almen gauge continues to be the finest gauge on the market. It has all the features needed to satisfy the most stringent specifications for the 2 type Almen gauge. The strip is mounted for accurate measurement so no spring or finger holding force will corrupt the reading accuracy.
This test is widely used on the shop floor as they are comparator measurements, calibrated originally from the MPa measurement results of the x -ray diffractometer. The aerospace industry applies the most rigid of standards when using Almen strips and checking devices. The SAE standard defines the requirements for equipment and supplies to be used in measuring the shot peening arc height and other surface enhancement processes.