International Conference on Shot Peening ICSP8
The Shot Peening Conference ICSP 8, held every 3 years up to now, was organized this year the second time under Sponsoring Society Deutsche Gesellschaft fuer Materialkund e.V., Frankfurt.
The organization was in the hands of Mr. Peter Paul Schepp, who is responsible for the wide varieties of all specific conferences that are managed by the DGM.
The DGM chose Garmisch-Partenkirchen for its Conference location again. The Alpine Scenery always attracts the visitors and admiring with the old fashioned but functional Lederhosen. However most of those who did attend complained about the poor Internet communication access in most of the Hotels initially, but did adopt the Bavarian Lifestyle pretty soon and took it easy with this shortcoming of internet access directly from the Hotel rooms.
We hope that none of the attendees lost any business because of this.
The selection of the individual technical and scientific contribution to the conference either by lectures or posters was managed by the Organizing Committee under Conference Chairman Prof. Lothar Wagner one of the pioneers in systematic research of the effects of shot peening on the fatigue properties of metallic materials.
In 1981 the first Shot peening Conference was initiated by Dr. Nikulari with his organizing team and held in Paris and the following conferences up to this year were held in 1984 in Chicago, 1987 in Garmisch- Partenkirchen, 1990 in Tokyo, 1993 in Oxford, 1996 in San Francisco and 1999 in Warsaw.
As at the previous conferences there was an opportunity for companies related to the Shot Peening Industries to exhibit on table-top showcases and by display panels as well.
In the first of the Peening Conferences the main focus was concentrated on showing the principal effects of Shot Peening on a wide variety of metals and its specific alloys with regard to the improvement of the performance and service life. The advantages of the basic tools for controlling the shot peening process were introduced as well.
Shot Peening has been proved ever since being an efficient and universal surface treatment process for enhancing the service life for a wide variety of structural and functional elements in mechanical engineering. The resistance of many kinds of material to cyclic loading in neutral and aggressive environments can be increased remarkably, in particular if the cyclic loading is superposed to by wear and/or galvanic corrosion.
Besides, the shaping and stretching of ribbed and non-ribbed sheet metals by means of impacts of shot is showing increased application. In particular the use of sophisticated centrifugal wheel technology has made the Peen Forming Process reliable and affordable for the aerospace industries.
Now since shot peening is very much established as production process, the process optimization and the productivity is coming more to the fore.
Focus of the ICSP8 & High Lights
The main focus during the current conference was to discuss the most important elements for shot peening and peen forming respectively, its optimized application and to urge the interdisciplinary communication and data exchange between the design- and production management.
For instance, the use of Almen Strips still is a very helpful tool for controlling the technological process parameters of specific shot peening treatment, once the parameters have been set but not more.
Every change of the process parameters will result in variations of Almen Strip reading, providing the Almen Strip measurement set-up is sensitive enough.
But the reaction of the work pieces with regard to the fatigue or service life to this variation of the Almen Strip Readings is not known, particularly not to the operator at the work bench and shot peening machine respectively. If the Almen Intensity for instance, that is shifting to the lower level, is “corrected” back towards the mean value simply by longer peening exposure time, this adjustment might not be of any harmful consequence in case of steel components. But in case of Al- or Mg- alloys this exertion of influence at site might be of detrimental consequence with regard to the fatigue and performance properties due to over peening effects.
The Almen Intensity only can be used as a controlling tool to monitor integrally all the parameters that are in use for the particular set-up. The Change of the Almen value always must have a source in changes of the process parameters. Very often the change of the size distribution of a work mix in use is the source of variations of Almen readings with the consequence of a modification of the residual stress profile.
However for better understanding and knowledge of the residual stress profile on the near-surface layers of the material introduced by shot peening the residual stress measurements on a regular basis can not be neglected any longer.
By the knowledge of the residual stress profile the modeling and the FE - Simulation technology to the fatigue properties can be applied already by the engineers at the design-phase
Lightweight design or design with regard to a fatigue-proof layout concept of components are no longer black boxes for structural designers as well as for deflection-proof shape designers in metal forming
The focus on test condition under non-unstable residual stress condition was another interesting part of the sessions.
The retardation of fatigue crack propagation in optimized residual stress fields is the main factor for the enhancement of the service life of components, providing the residual stress profile is showing stable condition as it is the case a “low”temperature application, preferably.
The focus on the surface condition ( surface texture ) is becoming the more important dominating factor of the fatigue properties, the more the thermally activated decrease and shift of the residual stress profile is becoming evident, as is the case at elevated operation or test temperatures.
Every mechanical surface treatment, from mechanical polishing over vibratory burnishing, shot peening to burnish (deep) rolling or laser surface peening is resulting in surface near cold-working effects due to local (micro) plastic deformations as we know. The resulting increase of dislocation density already does have remarkable potential for the increase of the fatigue performance on the one hand, but on the other hand, the components are more receptive to micro and macro notch factors due to increased local embrilement
At elevated operation temperatures the fatigue performance of components mainly is dominated and controlled by the resistance to fatigue crack nucleation that preferably is located at or near the surface for real components. Under this condition as well as in case of selected strain aging (by Short Time Annealing for instance) again the good olde smooth surface texture must not be forgotten for proper fatigue design at the stage of design, already.
While much about the influencing factors that are causing optimized shot peening processes were presented during the sessions and poster shows, all the attendees also had a chance to contact equipment manufacturers, suppliers of measurement devices and suppliers of shot peening media in the foyer of the conference center.
We would like to thank all these exhibitors at this point that sponsored the conference and contributed to a relaxed atmosphere and appropriate decoration of the quite successful event.
The organization of ISPC 9 will go back to its roots and will be held in Paris again in 2005.
We hope to see you all then again.
Submission of Abstracts
MFN would like to ask all the authors of the conference to submit the abstracts of their presentation to the editorial office together with their e-mail address over the Internet.
Since we are distributed over all continents we would like to offer the distribution of all of the short form of contribution also to those colleagues that did not have the opportunity or the budget to attend ISPC 8.
This way the interest in the demand for the proceeding might be enhanced and authors will have the opportunity to submit special prints of their papers to interested colleagues prior to the official publishing by the Main-Sponsor, the DGM.
We also would like all attendees to submit their e-mail address for further mailings with regard to international events related to shot peening.
MFN would like to say thank-you to all of the authors and would be pleased to be of any assistance in arranging international contacts within the International Shot Peening Community.