Browse Topic: Surface enhancement

Items (219)
This Aerospace Standard covers components of rotary flap assemblies to be used with portable equipment for peening of metal parts.The flap assemblies consist of a flap attached to a mandrel and shall be of the following sizes.
AMS B Finishes Processes and Fluids Committee
Shot peened components present a challenge for the structural analyst when nicks, scratches and gouges are discovered. A common repair scheme calls for blending away of the defect with an appropriate grit abrasive. Though the blending operation removes the defect, it also takes away a portion the beneficial compressive layer as well as the cold-worked material. Large repair facilities may have touch-up shot peen capability but technicians in a field repair setting typically do not. If the shot peen cannot be restored, the structural analyst must have a method to quantify the effect on fatigue life of the repaired part. The purpose of this technical paper is to substantiate analytical techniques for evaluating the fatigue life of a shot peened part after a blend operation. In addition to practical methods to estimate the magnitude of the residual stresses, a numerical method is introduced using finite element modeling of shot peen impacts with non-linear finite element code and validation by a simulated Almen strip.
Conklin, CraigFlores, RicBarrett, Arild
This specification covers the requirements for electrodeposited low-stressed nickel.
AMS B Finishes Processes and Fluids Committee
Study on Effect of Laser Peening on Inconel 718 Produced by DMLS Technique *CSP Meta Testing 2*2019-28-014610/11/2019
In Additive manufacturing, Direct Metal Laser Sintering (DMLS) is a rapid manufacturing technique used for manufacturing of functional component. Finely powered metal is melted by using high-energy fiber laser, by Island principle strategy that produces mechanically and thermally stable metallic component with reduced stresses, thermal gradients and at high precision. Inconel is an austenitic chromium nickel-based superalloy often used in the applications which require high strength and temperature resistant. It can retain its properties at high temperature. An attempt is made to examine the effect of laser shot peening (LSP) on DMLS Inconel 718 sample. Microstructure shows elliptical shaped structure and formation of new grain boundaries. The surface roughness of the material has been increased due to the effect of laser shock pulse and ablative nature. Macro hardness increased to 13% on the surface. Depth wise microhardness was investigated, found to be 17% increase on the sub-layer of the material due to the effect of a hardened matrix formed by precipitation hardening and grain size refinement attributed by laser shock peening. SEM analysis shows larger grains are being refined into smaller grains. The residual stress analysis result shows compressive residual stress values have increased.
Navin Kumar, NattuduraiYadav, Aditya ChandrakantRaja, KumarPrabhakaran, SubramanianNaiju, Chooriyaparambil DamodaranKalainathan, Sivaperuman
This specification covers the characteristics of glass beads used for peening, and provides for standard glass bead size numbers.
Surface Enhancement Committee
This SAE Recommended Practice Specification provides the procedures for using test strips per SAE J442 for peening processes.
Surface Enhancement Committee
ABSTRACT This paper presents the results of an experimental test program aimed at the investigation of the effect on fatigue life of blending surface damage on shot-peened parts. The test program was performed on shot-peened aluminum specimens where a surface damage was introduced on the specimen by machining a notch after the shot-peening operation. This notched area was then blended to a smooth surface before performing a four point bending fatigue test. The results showed little detrimental effect of the blending operation and, in some cases, improvement on the fatigue life of the specimen compared to a baseline shot-peened and undamaged specimen. These results were investigated with fractography, residual stress measurement using X-ray diffraction and a Discrete Element Model (DEM) - Finite Element Model (FEM) to simulate the blending and assess the redistribution of the residual stresses in the specimens.
Lapalme, MaximeOuellet, MarcBiron, Guillaume
ABSTRACT Accounting for effects of damage on the fatigue strength of metallic principal structural elements (PSE) is a requirement for fatigue tolerance evaluation of transport category rotorcraft. Parallel to the current structural test approach for showing regulatory compliance, an analysis method is sought. However, developing and executing an analytical compliance methodology has many challenges. One example is the stress state at the root of a flaw, and how that stress state interferes with the residual stress induced by specific processes such as shot peening. This paper presents an analysis method to determine the stress state at the root of a flaw with the presence of residual stresses. The method can quantify the effect of the residual stress on various flaw shapes and sizes, to avoid overly conservative assumptions in certification analysis.
Rajagopal, BalajiGreen, W.Reddy, ManjunathaLi, Xiaoming
This SAE Recommended Practice covers a high-quality corrosion-resisting steel wire, cold drawn, formed, and heat treated to produce uniform mechanical properties. It is magnetic in all conditions. It is intended for the manufacture of springs and wire forms that are to be heat treated after forming to enhance the spring properties. This document also covers processing requirements of the springs and forms fabricated from this wire.
Materials, Processes and Parts Council
This SAE Recommended Practice covers a high-strength corrosion-resisting steel wire, uniform in mechanical properties, intended for the manufacture of springs and wire forms. It also covers processing requirements of springs and forms fabricated from this wire.
Materials, Processes and Parts Council
Convection from a Simulated NACA 0012 Airfoil with Realistic Ice Accretion Roughness Variations2015-01-20976/15/2015
Changes in convection coefficient caused by the changes in surface roughness characteristics along an iced NACA 0012 airfoil were investigated in the 61-cm by 61-cm (24 in. by 24 in.) Baylor Subsonic Wind Tunnel using a 91.4-cm (36-in.) long heated aerodynamic test plate and infrared thermometry. A foam insert was constructed and installed on the wind tunnel ceiling to create flow acceleration along the test plate replicating the scaled flow acceleration the along the leading 17.1% (3.6 in.) of a 53.3-cm (21-in.) NACA 0012 airfoil. Two sets of rough surface panels were constructed for the study, and each surface used the same basic random droplet pattern created using the Lagrangian droplet simulator of Tecson and McClain (2013). For the first surface, the roughness pattern was replicated with the same geometry over the plate following a smooth-to-rough transition location noted in historical literature for the case being replicated. For the second surface, the heights of the roughness elements were scaled along the streamwise direction to match the roughness variations measured in the Icing Research Tunnel at NASA Glenn Research Center using laser scanning for an unswept 53.3-cm (21-in.) NACA 0012 airfoil exposed to a supercooled large droplet icing condition. The measured convective enhancements are comparable to historical measurements of convection from airfoils with simulated ice roughness.
Shannon, Timothy A.McClain, Stephen T.
STRESSONIC® Ultrasonic Shot Peening provides an economical shot peening solution to FAA Part 145 Repair Stations including Maintenance, Repair, and Overhaul facilities. This technology brings shot peening repairs to the shop floor, which eliminates the need to ship components to approved Conventional Shot Peening vendors, reducing shipping cost and turnaround time for a repair, as well as reducing the likelihood of damaged components due to shipping. Through a Small Business Innovative Research project with the U.S. Army, Avion and SONATS-Empowering Technologies qualified the use of the Ruggedized StressVoyager® on repairs for flight Critical Safety Items. Testing revealed that Ultrasonic Shot Peening induces a compressive residual stress comparable to Conventional Shot Peening methods used by Original Equipment Manufacturers, eliminating the concern of creating any stress concentration gradient when using this technology for repairs.
McClurg, KellyBuckner, RandyBrier, OlivierChateau, Frederic
The Digital Image Correlation Technique Applied to Hole Drilling Residual Stress Measurement2014-01-08254/1/2014
The residual stresses found in components are mainly due to thermal, mechanical and metallurgical changes of material. The manufacturing processes such as fabrication, assembly, welding, rolling, heat treatment, shot peening etc. generate residual stresses in material. The influence of residual stress can be beneficial or detrimental depending on nature and distribution of the residual stress in material. In general, the compressive residual stress can increase the fatigue life of material because it provides greater resistance for crack initiation and propagation. A significant number of improvements for residual stress measurement techniques have occurred in last few decades. The most popular technique of residual stress measurement is based on the principle of strain gage rosette and hole drilling (ASTM E837-01, destructive). Although this technique is effective for some applications, strain gages provide the localized or averaged data and cannot capture the peak or high resolution data when this technique is applied on high strain gradient areas. The measured strains are also highly influenced by the position of strain gages around the drilled hole. The improved measurement technique of 3D-Digital Speckle Pattern Interferometry (DSPI) with hole drilling can capture the full-field, high resolution and high accuracy in-plan and out-of-plan deformation data. However, DSPI is easily affected by environmental noises and it cannot measure in-plane and out-of-plane deformation simultaneously. The needs of Digital Image Correlation (DIC) techniques from industry have been increasing, especially in micro- and nano-scale mechanical testing applications mainly due to its relative easy implementation and utilization. Although DIC has a lower sensitivity than DSPI, it is more robust on spot measurements. Full field contour, displacement and strain data of specimens in any shape can be easily evaluated by DIC. This paper presents a new comprehensive residual stress measurement technique using 3D-DIC and hole drilling mechanism. In this, the residual stress measurement is performed in a full-field and no contact approach.
Chen, Yi-HsinChen, XuXu, NanYang, Lianxiang
This SAE Recommended Practice describes chemical composition and physical characteristic requirements for high-carbon cast-steel shot to be used for shot peening or blast cleaning operations.
Surface Enhancement Committee
This SAE recommended practice provides some procedure for determining shot peening coverage and relating coverage to part exposure to the media stream. Effectiveness of shot peening is directly dependent on coverage. Either incomplete or excessive coverage can be detrimental to fatigue strength and life.
Surface Enhancement Committee
This SAE Recommended Practice provides uniform procedures for using the standard shot peening Almen strips reported in SAE J442. Standard Almen strips are used to establish saturation, determine intensity, monitor repeatability of the shot peening machine operations, and can be used to predict a desired result on a part. It is recommended that the standard Almen strip A be used for intensities that produce arc heights of 0.10 mm A (0.004 in A) to 0.60 mm A (0.024 in A). For intensities below 0.10 mm A (0.004 in A), the standard N strip is recommended, and for intensities above 0.60 mm A (0.024 in A), the standard C strip is recommended. Use of SAE 2597 Computer Generated Shot Peening Saturation Curves is voluntary, existing shot peening processes that do not take advantage of computer generated saturation curves need not be changed to meet the requirements listed herein. The process of shot peening, in common with many other processes, cannot at present be adequately controlled by nondestructive inspection of the peened parts, therefore, it is necessary to control the process itself to achieve consistent, reliable results.
Surface Enhancement Committee
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