FAQs
Frequently Asked Questions (FAQs) About Laser Peening
Why is LaserPeen® processing more effective than shot peening?
The compressive residual stresses developed by LaserPeen® processing are much deeper than those produced by shot peening (typically in the range of 0.040″ to 0.060″ from the surface versus about 0.005-0.010″ for shot peening – up to ten times deeper. The deeper compressive residual stresses provide impressive gains in fatigue strength and fatigue life. Also, LaserPeen® processing does not roughen the surface of the part like shot peening, where aggressive peening can actually reduce fatigue life.
How much are fatigue strength and fatigue life improved?
The benefits of LaserPeen® processing depend somewhat on the part geometry, materials, and processing parameters. Greater benefits are achieved when the processing conditions are tailored for the specific part. Typical improvements in fatigue strength in thick parts after LaserPeen® processing are 25-50% higher than for untreated or shot peened parts, and can be much higher in thin sections. Therefore, fatigue life (number of cycles to failure) is often orders of magnitude longer compared with untreated or shot peened parts.
What does LaserPeen® processing do to the surface finish?
The opaque overlay coating used in LaserPeen® processing prevents any surface melting. Surprisingly, LaserPeen® processing is a mechanical process (shock hardening) rather than a thermal treatment. The surface finish is not roughened. Typically, the Ra finish is preserved after LaserPeen® processing. After LaserPeen® processing, the treated surface typically has a slightly wavy appearance from the pulsed laser spots. Although slightly visible, the waviness is typically only about 0.0002-0.0003″ deep. This is not a problem for most applications, even on machined surfaces. The visible indications of LaserPeen® processing may be removed with a light glass bead blast or other mild media polishing techniques when required, while the compressive residual surface stresses are retained. Also, the deep residual compressive stresses from LaserPeen® processing are not lost after subsequent finishing operations as is the case with shot peening where the effect is superficial.
Are the LaserPeen® process and equipment patented?
Yes, LSP Technologies, Inc. has an extensive portfolio of patents, which are available for license, covering many aspects of laser peening and laser peening equipment.
Do you LaserPeen® process the entire surface?
Because LaserPeen® processing is accomplished by a series of directed laser pulses, it is seldom necessary to treat the entire surface. Parts are treated cost-effectively and efficiently by LaserPeen® processing the specific areas prone to premature failures.
How fast is LaserPeen® process?
The time to process a part depends on the number of pulses required to cover the area to be treated. This may range from less than a minute for relatively small areas to a few hours for complex parts with large areas to be treated. Processing time can be expedited considerably when part handling is automated for production.
Is LaserPeen® processing affordable?
Yes! LaserPeen® processing is now very affordable for most applications.
We are constantly improving the LaserPeen® process and expect that the cost of LaserPeen® processing will continue to fall as the technology matures and broader use of the technology is made throughout industry. The cost of LaserPeen® processing depends on a number of factors, including: the size of the areas to be treated, the production quantity, and the extent of automation of material handling steps, among others. In the near term, the cost of LaserPeen® processing will not be as low as the cost of shot peening — where the benefits are modest. However, LaserPeen® processing is most applicable for fatigue-prone components in critical applications where gains in reliability and performance, or opportunities to make design improvements are desired.
How can LaserPeen® processing improve strength and durability for the following metals?
Click alloy below for residual stress data:
Ti-6Al-4V Laser peening Ti-6Al-4V Residual Stress Plot
IN 718 Laser peening IN 718 Residual Stress Plot
Aluminum 2024-T3 Laser peening Aluminum 2024-T3 Residual Stress Plot
Click items below for fatigue data:
Fatigue Curve for Aluminum Alloy 7050 Laser Peening aluminum fatigue data
Crack Initiation and Propagation for Aluminum Alloy 7075 Laser Peening Aluminum Crack Initiation and Propagation
Fatigue Crack Growth Rate for Ti-6Al-4V Laser Peening Fatigue Crack Growth Laser Peening Fatigue Crack Extension
Fatigue Testing of Ti-8-1-1 F101 Blades with FOD Damage Fatigue Siren Tests of Titanium Blades
Fretting Fatigue for Ti-6Al-4V Laser Peening Fretting Fatigue Plot
How can I learn whether LaserPeen® processing will work for my application?
Please contact us, and we will be happy to discuss how we can work together to explore LaserPeen® processing for your applications.
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