A seminar report onLOW PLASTICITY BURNISHING

OutlineNeed of Surface enhancementWhy LPB?ProcessIt’s BenefitsProcess Design ProtocolAdvantagesApplicationConclusionReferances

Need of Surface enhancement To minimize sensitivity to fatigue

Stress corrosion failure mechanisms

Surface enhancement process• Shot peening• Deep Rolling• Low Plasticity Burnishing (LPB™)• Controlled Plasticity Burnishing• Controlled covrage peening• Laser shock peening

Why should go for LPB?• Surface Treatment Speed Cold work Depth

• Shot Peening Fast High 15-50% ˜0.2 mm  

• Gravity Peening Fast Lower 10-20%

˜0.5 mm

• Low Plasticity Burnishing (LPB)

Moderate Low 2-5% ˜1mm ›7+mm

• Deep Rolling Moderate High 10-50% ˜1 mm+

• Laser Shock Peening (LSP)

Slow Low 5-7% ˜1-2 mm

Low Plasticity Burnishing (LPB™)

SchematicLPB™ uses a patented constant volume hydrostatic tool 

design to "float" the burnishing ball continuously during operation, regardless of the force applied.

Benefits Fatigue Life Extension Damage Tolerance ImprovementManufacturing DamageStress Corrosion Cracking and

Corrosion FatigueWeight Reduction Material SubstitutionPerformance Improvement

Process

Tool is synchronized with the CNC tool positioning, using either CNC machine tools or industrial robots.

Highly repeatablePrecise reproduction in the manufacturing

environment.Minimize operator interactionProcessing accuracy within 0.1%

Process Design Protocol

Total Engineering SolutionsTurn Key Solution for fatigue & stress corrosion

cracking problems.Step 1: Applied Stresses Step 2: Fatigue Design Step 3: Residual Stress Modeling Step 4: Compression ValidationStep 5: Fatigue Life VerificationStep 6: Processing Tools & CodeStep 7: Statistical Quality ControlStep 8: Turn-Key Production

Finite Element Analysis

Lambda provides the design of the optimal residual stress field and the range of compression allowable in production, along with the necessary tooling for LPB™

processing as part of the non-recurring engineering supporting each 

LPB™ application.

Residual Stress

Lambda’s unique combination of residual stress and 

cold work measurement, fatigue design, processing and 

testing capabilities provide the means to select and design

surface enhancement processes for optimal component

performance.

Effect of LPB on HCF Performance and FOD Tolerance:

HCF Result 38% increase in the endurance limit for LPB (>620 MPa

(>90ksi)) compared to shot peening (~448 MPa (~65 ksi)) after exposure to 425°C (795°F) for 10 hrs.

Increase in the HCF fatigue strength at 2x106 cycles for LPB over shot peening for either 525°C or 600°C exposure for 100 hrs.

The deep compressive layer produced by LPB is more effective in retarding crack growth, even after thermal exposure, because of the minimal thermal stress relaxation and the greater depth of the compressive layer.

Lives superior to that of shot peening even without FOD.

Quality Control Process Monitoring

Advantages and Benefits • Low capitalization costs.• Fewer chances for human error.• No specialized or remote facilities. • 100% QA• LPB™ causes no surface damage.• Applicable to arbitrary shapes and

directions.• A deep compressive layer• There is no possibility of internal

fracture• LPB™ can reduce inspection

requirements, achieving maximum safety at a minimal cost.

• LPB™ has the ability to improve HCF and SCC or mitigate damage  

Application Mitigation of Damage Mechanisms Fretting Stress Corrosion Cracking (SCC) Stress Concentrations Corrosion Pitting Foreign Object Damage (FOD) Weld Induced Tension Corrosion Fatigue

Applications by Use and Industry Aircraft Propulsion Aircraft Structures Medical Implants Nuclear/Power Generation

Conclusion From the all study of this , it gives the better

understanding of low plasticity burnishing LPB, and its significance in todays industry.It is most efficient & beneficial suface enhancement process.

Necessary to improve performance & reduce metal fatigue,SCC & corrosion fatigue failures.

Life of component increases.

Referances

Websites:www.lambdatechs.com/html/documents/

Aa_pp.pdfwww.sufaceenhancement.com/techpapers/

729.pdfwww.grc.nasa.govwww.techbriefs.com/index.php?

option=com_staticxt&staticfile=brief/Aug02/LEW17188.html

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