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Showing papers on "Peening published in 1991"


Journal ArticleDOI
21 Oct 1991-Wear
TL;DR: In this paper, the authors investigated the effects of cavitation on steel samples made of steel and found that the changes observed in the material are similar to the events produced by flow cavitation or shot peening.

46 citations


Journal ArticleDOI
30 Nov 1991-Wear
TL;DR: In this paper, a series of rolling contact fatigue tests has been done using a carburized steel with and without shot peening and continuous observations were carried out on the initiation and propagation of cracks.

32 citations


Journal ArticleDOI
TL;DR: In this paper, a general method of determining the optimal peening intensity pattern required to produce an arbitrary aerodynamic contour while controlling in-plane displacements is presented, using the finite element method to model the effects of shot peening.
Abstract: Shot peening is a viable method for the forming of aircraft wing skins. Presently, geometric methods used to calculate peening intensity patterns are approximate. These methods are based on simplifying assumptions which are not valid for complex contours. The scope of the work presented in this paper is to develop a more accurate method of predicting peening intensity patterns. A general method of determining the optimal peening intensity pattern required to produce an arbitrary aerodynamic contour while controlling in-plane displacements is presented. The finite element method is used to model the effects of shot peening. Inversion of the equations to determine an exact solution for the peening intensity pattern is impossible. An approximate solution is found through numerical methods taking into account contour accuracy and peening intensity magnitudes. The resulting procedure produces accurate and reasonable results for the test cases presented, (computer simulations). Verification of the procedure will be completed when the system is field tested on an actual wing skin.

26 citations


Patent
26 Nov 1991
TL;DR: In this article, a steel wire is subjected to coiling, nitriding, and shot peening, and the produced coil spring is given a residual stress, wherein the shot-peening processes is composed of a first shot-penalization process, a low-temp. annealing process, and a second shot-petrol peening process which uses smaller shots than those used in the first shotpeening process.
Abstract: PURPOSE: To provide a coil spring, whole fatigue strength is enhanced by giving a large residual stress through a simple process by means of optimization of the conditions under which a spring with high anti-fatigue property is subjected to the shot peening process. CONSTITUTION: A steel wire is subjected to coiling, nitriding, and shot peening, and the produced coil spring is given a residual stress, wherein the shot peening processes is composed of a first shot peening process, a low-temp. annealing process, and a second shot peening process which uses smaller shots than those used in the first shot peening process. COPYRIGHT: (C)1993,JPO&Japio

20 citations


Journal ArticleDOI
TL;DR: In this paper, an investigation of the influence of hammer peening on fatigue crack initiation and propagation in high-strength steel has been performed using edge notch specimens, and the results have been used to develop an analytical model to predict the fatigue crack growth rate in peened materials, based upon the compressive residual stress effect.

20 citations


Journal ArticleDOI
TL;DR: In this article, the effect of shot-peening on the fatigue behavior of the tested components, both theoretical and experimental techniques were considered, and the results of both materials reveal that a life improvement of up to 50% can be attained at 35% coverage level.
Abstract: The achievement of full-coverage during the application of shot-peening to critical components represents a major concern in the aerospace and power generation industries. It has been accepted, for many years, that full-coverage of such components is needed to attain the beneficial fatigue-life effects of the treatment. It has also been proposed, by a number of industrialists, that partial-coverage may apparently shorten the fatigue-life of the component because of the presumed presena of tensile residual stresses in the uncovered areas. Three aspects of the investigation were accordingly examined. The first deals with the accurate nirasurcnwnr of peening coterage using a three-dimensional surface profilometer arrangement. The second deals with the development of fatigue crack growth data for fully- and partially-peened components using an instrumented rotating-bend fatigue rig. The third deals with monitoring the residual stress field associated with different peening-coverage using the dissection method. In order to highlight the effect of the treatment upon the fatigue behaviour of the tested components, both theoretical and experimental techniques were considered. In the theoretical work, three-dimensional finite element analysis of circumferentially cracked notched and un-notched cylindrical components was considered in the development of the corresponding stress-intensity factor (K,) under bending loads. The stress-intensity factor vs crack length relationship was subsequently used in the experimental determi- nation of fatigue crack growth rate data at the different stress levels examined. Accordingly, room temperature rotating-bend fatigue tests were conducted on specimens made from medium carbon steel 080 M40 (En 8) and aluminium alloy (707ST6). Surprisingly, the results of both materials reveal that a life improvement of up to 50% can be attained at 35% coverage level.

19 citations


Journal ArticleDOI
TL;DR: In this paper, the influence of prior surface condition and shot peening treatment on the bending fatigue strength of a standard Si-Cr spring steel (SS 2090) was investigated.
Abstract: The influence of prior surface condition and of a shot peening treatment on the bending fatigue strength of a standard Si–Cr spring steel (SS 2090) has been investigated. This steel was initially h...

15 citations


Patent
23 Sep 1991
TL;DR: In this article, the authors proposed a method for measuring shot peening coverage, which employed an automated computer analysis of the peened surface coverage by analyzing surface line traces to determine when a particular surface has been surface hardened enough.
Abstract: This invention relates to methods for measuring surface treatment coverage, and more particularly, to such methods for measuring shot peening coverage. Such methods generally employ an automated computer analysis of the peened surface coverage by analyzing surface line traces to determine when a particular surface has been surface hardened enough.

14 citations


Patent
25 Jan 1991
TL;DR: In this article, a steel wire rod is cold drawn and an oil tempered steel wire is formed by executing quenching and tempering treatment, then shot peening is executed.
Abstract: PURPOSE: To improve fatigue resistance and durability by successively applying coiling formation low temp. annealing, bearing surface grinding, gas nitriding, shot peening and low temp. annealing to a steel wire rod. CONSTITUTION: The steel wire rod is cold drawn and, after that, an oil tempered steel wire is formed by executing quenching and tempering treatment. A coiled spring is formed by cold coiling it after electrical polishing. After annealing the coiled spring at a lower temp., the bearing surfaces are ground. After that, gas nitriding is applied. Then, shot peening is executed. Next, low temp. annealing is executed. These stages are successively executed. The shot peening is constituted of 1st shot peening and 2nd shot peening in which shots having diameters smaller than them used in the 1st shot peening are used. In this way, compressive residual stress is imparted to a deeper part. COPYRIGHT: (C)1995,JPO

13 citations


Patent
23 May 1991
TL;DR: In this paper, the authors considered a method for using the nozzle for sandblasting or shot peening a workpiece consisting of a base and a finger, the finger having diameter small enough to allow it to be inserted into an aperture in the workpiece and the base having a bypass orifice therein which allows excess shot to exit the nozzle so that the nozzle will not clog with shot.
Abstract: A nozzle for sandblasting or shot peening a workpiece comprises a base and a finger, The finger having diameter small enough to allow it to be inserted into an aperture in the workpiece. The finger has a lateral opening therein to allow peening fluid to exit and impinge an interior wall of the aperture. The base has a bypass orifice therein which allows excess shot to exit the nozzle so that the nozzle will not clog with shot. A method for using the nozzle is contemplated wherein the nozzle is reciprocated and rotated within the aperture so as to subject the entire interior wall to the peening process.

12 citations


Patent
10 Jun 1991
TL;DR: In this article, the authors proposed a residual stress improvement by striking the surface of a metallic material by the impact of cavitation generated by a water jet under water or the underwater environment created in the atm. air, thereby imparting the residual stresses of surface compression to this metallic material.
Abstract: PURPOSE: To execute a residual stress improvement by striking the surface of a metallic material by the impact of the cavitation generated by a water jet under water or the underwater environment created in the atm. air, thereby imparting the residual stresses of surface compression to this metallic material. CONSTITUTION: The high-pressure water fed via a hose 2 and a conduit 15 from a high-pressure pump 1 is ejected into the water from a horn type nozzle 3 toward the metallic material 4 placed in the water in a tank 16 to positively generate the cavitation. The metallic material 4 is striken by the impact force generated by the collapse of the air bubbles to locally generate the strain above the yield point, by which the residual stresses of the surface compression are imparted to the metallic material. The nozzle 3 is moved along the material 4 by a moving mechanism 44. In another embodiment, the metallic material is placed in the atm. air and high-pressure water flow is ejected from the central ejection port of the nozzle into the local underwater environment formed by the water flow ejected from the ejection port in the outer peripheral part of the nozzle to generate the cavitation in same way, by which the residual stress improvement is similarly executed. COPYRIGHT: (C)1992,JPO&Japio

Patent
30 Jul 1991
TL;DR: In this article, tools and dies are made from a master pattern by making a hard chromium electroformed shell from the pattern and filling it with tool steel which is applied by spray deposition of molten particles, the deposit being continuously densified by peening as it is made.
Abstract: Tools and dies are made from a master pattern by making a hard chromium electroformed shell from the pattern, supporting the pattern and filling it with tool steel which is applied by spray deposition of molten particles, the deposit being continuously densified by peening as it is made.

Patent
20 Sep 1991
TL;DR: In this paper, a circular direction shifting carriage was used to shift in the circular direction of the nuclear reactor pressure vessel to give a compressive residual stress by using water jet to the internal structure in a nuclear reactor as the object in the water.
Abstract: PURPOSE: To effectively give a compressive residual stress by using water jet to the internal structure in a nuclear reactor as the object in the water and peening the surface of the internal structure in the nuclear reactor. CONSTITUTION: This device is provided with a circular direction shifting carriage arranged at the upper part of a nuclear reactor pressure vessel 1 so as to shift in the circular direction of the nuclear reactor pressure vessel 1, a diameter direction shifting carriage as shiftable in the diameter direction of the nuclear reactor pressure vessel 1, masts 7, 9 hung on this diameter direction shifting carriage and divided into plural steps so as to vertically expand/shrink, a compressive residual stress giving means fitted to the lowest end parts of the masts 7, 9 and giving the compressive residual stress to the internal structure in the nuclear reactor and a residual stress measuring means. The residual stress in the internal structure in the existing nuclear reactor pressure vessel is changed into the compressive stress from tension stress in the water by the remote operation and the stress corrosion cracking in the internal structure in the nuclear reactor pressure vessel is prevented from happening. COPYRIGHT: (C)1993,JPO&Japio

Patent
28 Jan 1991
TL;DR: In this paper, a nozzle holder and a sensor for a pressure pot peening system is described, and the holder includes a 90° bend which is provided so that substantially the entire momentum of the mass of shot and air ejected from the nozzle can be sensed by the sensor.
Abstract: A nozzle holder and sensor for a pressure pot peening system is disclosed. The holder includes a 90° bend which is provided so that substantially the entire momentum of the mass of shot and air ejected from the nozzle can be sensed by the sensor and mass of shot and air ejected is not adversely affected if the hose from the shot peening system is moved. Also the holder can be oriented into a variety of positions and locations.

Patent
26 Feb 1991
TL;DR: In this article, a compression residual stress is imparted simultaneously with selectively removing a cementation abnormal layer only with a shot grain whose grain size is ≤ 0.3 and whose hardness is 600-750 Hv being projected at ≥200% coverage on the surface of a cemented part.
Abstract: PURPOSE: To improve the fatigue strength of a cemented part without deteriorating a product accuracy. CONSTITUTION: A compression residual stress is imparted simultaneously with selectively removing a cementation abnormal layer only with a shot grain whose grain size is ≤0.3 and whose hardness is 600-750 Hv being projected at ≥200% coverage on the surface of a cemented part. After this shot peening under special conditions, an ordinary shot peening for increasing the compression residual stress further as occasion demands is executed. COPYRIGHT: (C)1992,JPO&Japio

Journal ArticleDOI
TL;DR: Investigations show that residual stresses resulting from shot peening are reduced by additional bending of the plates, which means an improvement in quality of surgical implants.
Abstract: Shot peening can increase the fatigue strength of commercially available surgical plates made of 1.4435 alloy by 40% even in a corrosive environment. Our investigations show that residual stresses resulting from shot peening are reduced by additional bending of the plates. In such plates smaller tensile residual stresses were found than after polishing of the plates. Bending of polished plates results in considerable tensile residual stresses. The hardening achieved by shot peening is not reduced by bending. As the fatigue strength of soft materials depends mainly on the hardening and less on the residual stresses, only little influence of the changed residual stresses on the fatigue strength can be expected. Shot peening of surgical implants thus means an improvement in quality.

Patent
06 Nov 1991
TL;DR: In this article, an improved high-intensity rotary peening particle support of the type having a plurality of peening particles metallurgically secured to an exposed face thereof is presented, the support having a base composition consisting essentially of from about 0.08 to 0.34 weight percent carbon, the balance iron and a Ni-enriched layer which provides a hard, wear resistant surface.
Abstract: An improved high-intensity rotary peening particle support of the type having a plurality of peening particles metallurgically secured to an exposed face thereof is presented, the support having a base composition consisting essentially of from about 0.08 to about 0.34 weight percent carbon, the balance iron, and a Ni-enriched layer which provides a hard, wear resistant surface. A method of producing such a support is also described, the method including cold forming a peening particle support base composition as described, stress relieving, brazing peening particles to an exposed face of the support, austenitizing, quenching, and tempering the support to form a support having a Ni-enriched layer which is harder than the base composition.

Patent
17 Apr 1991
TL;DR: In this paper, the authors proposed to enhance the fatigue resistance by applying a compressive load in the tooth trace direction of a gear, thereby inducing tensile stress in the form direction corresponding to Poisson's ratio.
Abstract: PURPOSE:To enhance the fatigue resistance by applying a compressive load in the tooth trace direction, of a gear thereby inducing tensile stress in the tooth form direction corresponding to Poisson's ratio together with applying shot-peening in this state. CONSTITUTION:When a compressive load is given to a gear 1 in its tooth trace direction, using a loading jig 2, tensile stress is induced in the tooth form direction. In this state, shot-peening by means by shot-particles 3 is applied to the gear 1. As a result, the compressive stress, which is greater than the case of ordinary shot-peening, remains in the gear 1. In such a gear 1, since this residual compressive stress cancels out the tensile stress due to the load applied to the gear, the fatigue limit can remarkably be increased.

Patent
10 May 1991
TL;DR: In this paper, the sensor shaft is heated above a transformation point A2 and residual stress is redistributed to make the permanent deformation larger than before the shaft was heated, which improves the sensor characteristics.
Abstract: PURPOSE:To improve the sensor characteristic of the sensor shaft after carburization, quenching, tempering, etc., by heating the sensor shaft above a transformation point A2 after a process wherein tensile permanent deformation is generated in the surface of the sensor shaft. CONSTITUTION:The process wherein the tensile permanent deformation is gener ated in the surface of the sensor shaft by shot peening, rolling, etc., is applied and then the permanent deformation generated in the shaft surface balances with the internal part of the shaft which is not deformed permanently to obtain balance with deformation less than the give permanent deformation. Then the sensor shaft is heated above the transformation point A2 and residual stress is redistributed to make the permanent deformation larger than before the shaft is heated. Consequently, even the sensor obtained merely by short peening like the sensor shaft after carburization, quenching, tempering, etc., is improved in hysteresis and sensor characteristics.

Patent
03 Apr 1991
TL;DR: In this article, the authors proposed a shot pre-accelerating device which is positioned before a main mixing chamber and makes use of an induction principle and an internal structure for multi-time shot induction to enable shots obtain a high speed as soon as getting away from the nozzle.
Abstract: The utility model belongs to the improvement of a nozzle for air-operated shot-peening equipment. The utility model adopts a shot pre-accelerating device which is positioned before a main mixing chamber and makes use of an induction principle and an internal structure for multi-time shot induction to enable shots obtain a high speed as soon as getting away from the nozzle. Compared with an ordinary nozzle, shot-peening by the improved nozzle is provided with a stable amount and a stable speed. The utility model which has the advantages of simple structure, compactness and practicality is particular suitable for sealing inner cavity shot-peening with a small diameter, a deep hole and a small opening, and is suitable for occasions in need of high peening intensity but unavailable to use a large geometric sized nozzle or an air source with high gas supply pressure.

Journal ArticleDOI
TL;DR: In this paper, the merits of the peening effect in improving the fatigue resistance of compounds and the machines that perform the task are discussed. But there is a lack of information about the process but now a significant increase in studies dealing with peening is helping to overcome problems.
Abstract: This paper discusses the merits of the peening effect in improving the fatigue resistance of compounds and looks at machines that perform the task. There is a lack of information about the process but now a significant increase in studies dealing with peening is helping to overcome problems.

Patent
28 Aug 1991
TL;DR: In this paper, a shot pressure hose is attached to a shot inlet of a pipe shaft, and an oblique projecting nozzle is formed by the axis of a projection shot on the vertical plane, so as to become a range of 30-40 deg, through which the vertical planes of the workpart and the horizontal plane orthogonal with the former are subjected to shot-peening at the same time.
Abstract: PURPOSE:To enable it to peen both vertical and horizontal planes of a workpart in the same degree as well as to improve the workpart in quality by performing the peening work for the vertical plane and the horizontal plane orthogonal with the former in a way of making a vertical-plane projection angle, being formed by the axis of a projection shot on the vertical plane, so as to become a range of 30-40 deg.. CONSTITUTION:A shot pressure hose 21 is adjoined to a shot inlet 19 of a pipe shaft 3, and an oblique projecting nozzle 25, forming a bending passage 28 capable of projecting a shot to the vertical plane of a workpart W in an oblique direction of 30-40 deg. at the tip end side, is connected to a shot outlet 24 of the pipe shaft 3. With this constitution, a vertical-plane projection angle being formed by the axis of a projection shot on the vertical plane, is set to a range of 30-40 deg., through which the vertical plane of the workpart and the horizontal plane orthogonal with the former are subjected to shot-peening at the same time.

Patent
29 Jan 1991
TL;DR: In this paper, the authors proposed a method to easily clean the surface of a metallic material and to form a chemical conversion coating excellent in rust-preventing property and adhesion by carrying out peening treatment by using an abrasive material or blasting material where specific chemical coating material is allowed to adhere at the time of applying treatment of rust prevention, coating, plating, etc.
Abstract: PURPOSE:To easily clean the surface of a metallic material and to form a chemical conversion coating excellent in rust-preventing property and adhesion by carrying out peening treatment by using an abrasive material or blasting material where specific chemical coating material is allowed to adhere at the time of applying treatment of rust prevention, coating, plating, etc., to the surface of a metallic material. CONSTITUTION:At the time of carrying out surface treatment for the purpose of improving rust-preventing property at the surface of a metallic material and improving the adhesion of plating film and paint film in plating and coating, blasting or peening treatment is exerted by using a granular grinding or blasting material, such as grits and glass beads, in which one or >=2 kinds among phosphate, chromate, oxalate, and silicate are stuck to the surface by means of a pressure sensitive adhesive. Since the surface of the metallic material can be cleaned by a simplified process and a chemical conversion coating due to the salts can be formed, a chemical conversion treated surface excellent in rust-preventing property and adhesion of plating film and paint film can be obtained.



Journal ArticleDOI
TL;DR: The compressive strength of hard-alloy balls depends mainly on the peening regimes; it is therefore necessary to inspect the products thoroughly at the given production stage as mentioned in this paper, and therefore it is necessary to perform a thorough inspection at any stage of the production process.
Abstract: The compressive strength of hard-alloy balls depends mainly on the peening regimes; it is therefore necessary to inspect the products thoroughly at the given production stage.

Journal ArticleDOI
21 Oct 1991-Wear
TL;DR: In this paper, a comparative study of the degradation of S-460 shot due to target hardness was carried out by impacting the shot against white and gray cast iron targets in a laboratory testing machine and against a WTB6 production blasting machine.

Journal ArticleDOI
TL;DR: In this article, the structural defect elimination model is proposed to explain the origin of the tensile stress as well as the relations between the stress and the deposition conditions, and the defect elimination is explained qualitatively.
Abstract: Co-Cr alloy thin films are considered as an applicable perpendicular magnetic recording medium, and their mechanical properties such as internal stress can not be neglected. In this experiment, Co-Cr films are deposited on glass substrates by D. C planar magnetron sputtering, and the effects of film thickness, Ni-Fe underlayer as well as substrate temperature on the stress are studied respectively. The stresses are all tensile in all cases, and the stress existing at the film-substrate interface is very small. According to the above experimental results and the structure analysis of the films, the atomic peening effect produced by the rebounded working gas atoms can be negligible, and the stress is thought to originate from the film growth process but not from the inter-facial effect. Therefore, the structural defect elimination model is proposed (here the defects mainly include vacancies and grain boundaries). With this model, the origin of the tensile stress as well as the relations between the stress and the deposition conditions are explained qualitatively.

Book ChapterDOI
01 Jan 1991
TL;DR: In this paper, the influence of shot peening over corrosion, stress corrosion, corrosion fatigue and fracture behavior of carbon steel has been studied, and a laboratory equipment for stress corrosion testing vas designed and fabricated (vertical type).
Abstract: The influence of Shot Peening over corrosion, stress corrosion, corrosion fatigue and fracture behaviour of carbon steel has been studied. A laboratory equipment for stress corrosion testing vas designed and fabricated (vertical type). Further, it was modified into ‘horizontal type’ for easier loading and unloading of the test specimen. Test specimens were peened manually. The controlled peening showed that there was reduction in loss of weight, improvement in stress corrosion resistance and corrosion fatigue resistance when combined with carburising treatment. Shot peening alone did not show any appreciable improvement in corrosion fatigue resistance. It was also observed that shot peening delayed rate of crack propagation for notched specimens.

Book ChapterDOI
01 Jan 1991
TL;DR: In this article, the residual stresses induced by peening are modelled as a function of impact characteristics: the impact energy, the nature of the peening medium and the mechanical behavior of the processed material.
Abstract: Modelling the residual stresses induced by peening requires the applied stress field to be known as a function of the impact characteristics: the impact energy, the nature of the peening medium and the mechanical behavior of the processed material. Shot size, material, and velocity and in some instances the impingement angle and the coefficient of friction of the contacting bodies are the main factors which have been taken into account.