MPa and Relationship to Almen Strips

Almen Strip Comparator

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 requirements for these checks, are specified in standards.

The aerospace industry applies the most rigid of standards when using Almen strips and checking devices.

How to Measure Residual Stress

Measurements – Imperial and Metric explanation

Imperial
Ksi means kilopound per square unit and is derived from psi(lbs/square inch).  Kilo, which is often used in the metric system basically means a thousand (1000).  It comes from the Greek word for 1000. Therefore, a kilopound is 1000 pounds.

Metric
A Megapascal (or MPa) is a variation on a pascal.   Mega in this case means 1,000,000 and again it means “great”.  As you may guess, when using MPa you are usually working with something heavy or with a high pressure!

Both ksi (kilopound per square inch) and megapascal (MPa) are units of pressure measurement – the former is an Imperial unit of measurement and the latter a metric unit.
Ksi values are commonly converted to MPa, as the metric system is the more widely used system of measurement.

Measurement Of Compressive Residual Stress Using X-ray Diffraction

A sub-surface compressive residual stress profile is measured using x-ray diffraction measuring equipment.

The X-axis is the measurement of the depth in mm or inches the Y-axis is measure of residual stress in ksi or MPa.

What Will Peening Do For My Components?

Shot peening is a cold work process used to enhance the life of metal components, to prevent fatigue, stress corrosion failures and prolong the product life for the component part.

Fatigue is the weakening of a material caused by repeatedly applied loads.  It is the progressive and localised structural damage that occurs when a material is subjected to a cyclic loading.

Fatigue occurs when a material is subjected to repeated loading and unloading.   If the loads are above a certain threshold point microscopic cracks will begin to form at the stress concentration points, such as the surface, sharp points in the deviation in shape and the internal grain structure. Eventually a crack will reach a critical size, the crack will elongate suddenly, and the component will break.

Process Water Recycling Systems

Industrial process water  re-circulation is the preferred water treatment method for so many applications.  Process water recycling systems can be connected to virtually any wet processing machine (and multiples of) and can make significant savings by way of reduced volumes of water (and compounds) used and their associated disposal costs.