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Controlled Shot Peening Preventing Failures MIC Services INNOVATORS IN TECHNOLOGY Metal Improvement Company Subsidiary of Curtiss-Wright Corporation Controlled shot peening Preventing failures Enhancing the performance of metals and materials www.metalimprovement.co.uk Controlled shot peening - preventing failures Metal Improvement Company (MIC) is a Component failure is often related to residual tensile stress global organisation specialising in metal and DESIGN CONSIDERATIONS - COST OF PERFORMANCE CRITERIA material surface treatments which enhance induced during manufacture. Subsequent severe working performance and extend the life of critical and/or unexpected conditions can eventually lead to Parameter selection - the choice of process have to be accurately and Intensity control components, enabling component designs to shot peening parameters is dependant repeatedly controlled. achieve their maximum potential. premature failure. on a variety of conditions: Shot peening intensity is the measure Controlled shot peening is different of the energy of the shot stream. It is Established in 1945, MIC has over 60 l knowledge of the application of the from most manufacturing processes in one of the essential means of ensuring operating divisions in Europe, USA, Canada Typical examples of premature failure are: The shot peening process - how it component that there is no non-destructive method process repeatability. The energy of the and Asia with on-site processing worldwide. works l component geometry to confirm that it has been performed shot stream is directly related to the We offer a quality controlled and cost l Metal fatigue to the proper specification. Techniques compressive stress that is imparted into l manufacturing method effective service, working in partnership to Controlled shot peening is the such as x-ray diffraction require the a component. Intensity can be increased l Corrosion fatigue meet our customer’s needs. bombardment of a surface with small high l mechanical properties of the base part be sacrificed to generate a full by using larger media and/or increasing l Stress corrosion cracking quality spherical media called shot in a material compressive depth profile analysis. the velocity of the shot stream. MIC division approvals, where appropriate, technically defined and controlled way. l l Intergranular corrosion strain sensitivity of the base material include: FAA, AS9100, NADCAP, ISO To ensure peening specifications are Other variables to consider are the l environment 9001:2000, ISO 9001:2008 plus other l Fretting The shot can be steel, stainless steel, glass being met for production batches, the impingement angle and peening media. specific OEM, company and industry or ceramic. l service conditions, loads and cycles following process controls must be Intensity is measured using Almen test l Galling approvals as required. l cost sensitivity maintained: media intensity, coverage, strips and must be conducted initially Each piece of shot striking the metal acts as l Spalling All the above must be considered shot direction and repetition. Equipment during set up and repeated at approved a tiny peening hammer imparting a small when deciding on parameter selection should be mechanised to ensure the intervals. l Wear indentation or dimple into the surface. and, equally important, maintained motion of component to shot flow is The action of impinging the surface yields Coverage control The services MIC offer induce residual throughout the life of the product in a consistent - hence the term controlled compressive stresses and so extend the material in tension, further movement shot peening. repeatable and consistent manner. Complete coverage of a shot peened component life in a wide range of is restrained by the core and a surface surface is crucial in performing high applications. residual compressive stress results. The Media control magnitude of the compressive stress is quality shot peening. Coverage is the Te nsion 0 Compression Shot peening is the most cost effective directly related to the yield strength of the Controlling shot shape and size will measure of original surface area that has and practical method of inducing surface base material and is approximately equal Stress from result in a residual compressively been obliterated by shot peening dimples. applied load residual compressive stresses which to 80% of that value in compression. Residual stress stressed layer on the surface of uniform Coverage should never be less than from shot peening enhance the performance and extend the Resultant stress magnitude and depth: 100% as fatigue and stress corrosion life of critical components. cracks can develop in any non peened Impact at high speed area that is not encased in residual creates a dimple compressive stress. Some strain sensitive Shot peening influence on applied stress - materials perform better with levels of Dimple algebraic reductions coverage in excess of 100%. Depth of compressive layer - this is the depth of the compressive layer resisting crack initiation and propagation. The layer depth can be increased by increasing the peening impact Metal Improvement Company energy, but section thickness has to be Poor shot shape and size will result in is a subsidiary of the Curtiss-Wright considered. A deeper layer is generally an irregular residual stress profile, stretched surface Corporation, a diversified international desired for crack growth resistance and excessive surface disruption and provider of highly engineered severe environmental condition. potential stress raisers: products and services to the Surface stress - this magnitude is Motion Control, Flow Control and usually less than the maximum Materials Treatment industries. COMPRESSION compressive stress, which is subsurface www.curtisswright.com but can be tailored to suit the application. Controlling the process Shot peening process To ensure reliability and repeatability the variable parameters of the shot peening INNOVATORS IN TECHNOLOGY MIC MARKETS INCLUDE: MIC SERVICES INCLUDE: l Aerospace l Controlled shot peening induces engineered residual compressive stresses l Architectural l Shot peen forming l Automotive creates curvature and corrects distortion l Chemical & food processing l Laser peening induces deeper residual compressive stresses l General & structural engineering l Engineered coatings l Marine improves performance, prevents corrosion and aids lubricity l Medical l C.A.S.E. (isotropic finishing) l Military removes surface asperities reducing friction l Off-road & earth moving equipment l On-site processing provides services on customers’ own premises l Oil, gas & petrochemical l Peentex (architectural finishing) l Power generation creates decorative and aesthetic texturing l Railways l Surface texturing applies a textured engineered finish l Peenflex mouldings protects against processing and handling damage EUROPEAN CORPORATE OFFICE USA COMPANY HQ PARENT COMPANY HQ Metal Improvement Company Metal Improvement Company Curtiss-Wright Corporation Hambridge Lane, Newbury 80 Route 4 East, Suite 310 10 Waterview Boulevard, 2nd Floor Berkshire RG14 5TU, UK Paramus, New Jersey 07652, USA Parsippany, New Jersey 07054, USA Tel: +44 (0)1635 279621 Tel: +1 (201) 843 7800 Tel: +1 (973) 541 3700 Email: [email protected] Email: [email protected] Web: www.curtisswright.com Web: www.metalimprovement.co.uk Web: www.metalimprovement.com Metal Improvement Company Subsidiary of Curtiss-Wright Corporation design/production: www.publicityproject.co.uk.
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