An Almen strip is a thin strip of
SAE 1070
SAE or Sae may refer to:
Science and technology
:
* Selective area epitaxy, local growth of epitaxial layer through a patterned dielectric mask deposited on a semiconductor substrate
* Serious adverse event, in a clinical trial
* Simultaneous Auth ...
steel
Steel is an alloy made up of iron with added carbon to improve its strength and fracture resistance compared to other forms of iron. Many other elements may be present or added. Stainless steels that are corrosion- and oxidation-resistant ty ...
used to quantify the intensity of a
shot peening
Shot peening is a cold working process used to produce a compressive residual stress layer and modify the mechanical properties of metals and composites. It entails striking a surface with shot (round metallic, glass, or ceramic particles) with ...
process.
Developed and patented by John O. Almen, the strip was originally supported by 2 knife edges; later improvements see it being supported on 4 small balls. The strip is placed in the chamber in place of the item to be shot peened, usually near to an area of the item where the result is deemed critical, sometimes located by a special fixture. Compressive stress introduced by the peening operation causes the strip to deform into an arch, which is measured using a gauge.
Almen strips are classified into 3 types: 'A', 'N', and 'C'. They differ in their thickness, while they have the same width and length.
*Almen strip of "A" type is predominantly used for shot peening with cast shot or
cut wire shot
Shot peening is a cold working process used to produce a compressive residual stress layer and modify the mechanical properties of metals and composites. It entails striking a surface with shot (round metallic, glass, or ceramic particles) with ...
.
*"N" type strips are used usually for glass bead peen and ceramic bead peen.
*"C" type almen strips are used more rarely and are thicker than the other types.
Although similar, the specification for Almen strip dimensions of the same type slightly vary from one company/organization to another. The Almen strips are made from
plain carbon steel SAE 1070
SAE or Sae may refer to:
Science and technology
:
* Selective area epitaxy, local growth of epitaxial layer through a patterned dielectric mask deposited on a semiconductor substrate
* Serious adverse event, in a clinical trial
* Simultaneous Auth ...
and have
hardness about 45
HRC.
This test is widely used and the requirements for check are specified in standards.
The most rigid requirements are applicable for Almen strips and checking devices (Almen gauges) used in the aerospace industry. The generic requirements can be found in
SAE
SAE or Sae may refer to:
Science and technology
:
* Selective area epitaxy, local growth of epitaxial layer through a patterned dielectric mask deposited on a semiconductor substrate
* Serious adverse event, in a clinical trial
* Simultaneous Auth ...
specifications.
Another operation to gauge the intensity of a shot peening process is the use of an
Almen round, developed by R. Bosshard.
External links
Shot Peening Universe FAQIndustrial Metal Finishing, Inc. Glossary
Comprehensive glossary of Metal Finishing terms and process descriptions, including Almen Strip
Peening Accessories GmbH:
Comprehensive information about peening, including Almen strips
About Almen strips
*Certified Almen Strip Supplier https://pgmetalcomp.com/capabilities
Shot peening
Measurement
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