Newsletter 3 January 2017

Transcription

1 Newsletter 3 January 2017 Editorial It is a very exciting time in the WRIST project, with 18 months of the project now over, and 18 left to go. We have just had our 4th consortium meeting, in Leipzig, Germany, at the premises of Goldschmidt Thermit, where the new aluminothermic welding process was demonstrated on their prototype, named ALFONS! As you can see from the photographs, this was very impressive and the partners look forward to the detailed tests. For the new orbital friction welding the designs have at last been finalised and the parts are being machined, and with deliveries due in the next few weeks, it is hoped that we can have the prototype up and running in the new year, ready for testing. In this issue we have an interview with Dr. Ing. Jan Hantusch, Head of Pre- Development at the GTG Technology Innovation Center, who explains more about the developments they have made. I hope you enjoy this, and I look forward to writing to you all again with our next issue, and where hopefully we will have photos and more information on the orbital friction welding prototype. Warmest wishes Koen Faes WRIST Project coordinator On-going status Once again, during the first 18 months, four main technical workpackages have been running. Below you will find the on-going status and achievements for each of these WPs. For an overview of the project, please see the article "WRIST in a nutshell' in previous newsletters WP1 Requirements Analysis WP1 has built on the existing state-of-the-art, to independently demonstrate the benefits of more sophisticated finished weld geometry controls, with respect to rail forces and subsequently on rail damage. In doing so associated deficiencies in the existing relevant Euro Norms have been highlighted and consequently recommendation for the review of the geometric controls of finished weld geometry in the relevant Euro Norms have been made. The workpackage has derived two possible methods for assessing currently uncontrolled aspects of finished weld geometry and a number of welds have been measured in unprecedented detail, using an advanced 3D laser measurement prototype developed within the project. The use of such measurements can open the door for a more advanced and reliable control of the weld geometry by accounting for the true wheel-rail motion across the width of the weld. Bespoke tests, additional to those mandated in European specifications, have been recommended to better assess the resistance of the welds produced by the proposed welding process developments to the known degradation mechanisms. WP2 New aluminothermic welding process Within WP2 four key technical deliverables and prototypes are expected from the work here and three prototypes have been delivered in the past six months. Below is a short summary of these three achievements, as the followed by an interview with Dr. Ing. Jan Hantusch. 1

2 Process Control System The process and machine control system collates all the incoming data from the welding process and it must generate and document the manual inputs of the operator, the specified process parameters and the measured values from sensors during the sequence of the automated process steps. Furthermore, it needs to record the consumables in order to enhance quality assurance and traceability. This prototype of the process control module can be seen in the images below Controlled Compressive Forces Process Control tool and interface This is the main development of the work in WP2 and the first prototype (Module 1) has been delivered. The task of achieving the relative geometric alignment of the rail ends to each other, the introduction of directed pressure forces for compression or forging of the weld joint and the shearing of excess weld material has been achieved with the development of an automated rail alignment unit, forging unit and shearing unit (module 1.0). The final module consists of a metallic, highly rigid supporting skeleton, a hydraulic for generating the necessary drive and pressing forces as well as a sensor system for controlling the process. This module 1.0 has also been designed so that in addition to tests for welding, development tests can be performed. In this way it is possible to later amend the concept of the clamping cylinder to provide less clamping force, thereby reducing the number of clamping units and thus approaching more closely to a manageable final weight for in the field. Based on its uses (ALigning, FOrging and Shearing) it has been nicknamed ALFONS. ALFONS (module 1) 2

3 Weld Finishing Technology The weld finishing technology is a machine that ensures the contours and surfaces are restored following the alumina-thermic welding process to comply with standards, and the accelerated cooling of the welded joint. Moreover, the profile must be monitored during the process, and the surface must be monitored and evaluated afterwards. The weld finishing tool being hoisted into place Enhanced Cooling System The final prototype of the enhanced cooling system has been delivered, as pictured below. This new cooling system brings several benefits to welding teams in the field in order to enhance productivity as it helps to create a geometrically stable joint enabling accurate profile grinding. It also allows for the ability to complete final weld inspection within a welding shift. It enables a shorter time in application and removal of hydraulic tensors when restoring SFT (i.e. Closure welds) and ensures high integrity weld with fully pearlitic microstructures. Finally, as it is portable and robust it is simple to use and easy to train welders in its use. 3 Nozzle Mist Spray Enhanced Cooling Head (Module 1.1) 3

4 Interview with Dr. Ing. Jan Hantusch, Head of Pre-Development at the GTG Technology Innovation Center. Q: The Goldschmidt Thermit Group has been providing thermite welding for over 120 years and the Goldschmidt process still represents the state of the art for the welding of rails. How will the advances in WRIST improve the process? A: The WRIST project should serve to help develop basic technologies designed to mechanize and automate work processes which are today manually carried out by the welder so that on the one hand the welder is relieved from heavy routine work and also on the other hand that the Jan Hantusch quality of the weld is less dependent on the abilities of the respective welder. Furthermore, the WRIST project should also review whether subsequent forging with a thermite weld has a positive influence on the mechanical characteristics of the thermite weld. An additional goal is the recording and provision of data during and for the welding process. For this purpose a system is to be developed which can control such a forging manipulator, but which is also able to record process data and make such data available for subsequent analysis. Q: How have these requirements been addressed? A: In WP 2 a number of different prototypes were developed. The main system is realized as a hydraulically driven forging manipulator to enable the aligning of the rail, the shearing process after the weld, and the forging process. The main system was therefore given the name ALFONS. ALFONS stands for ALigning, FOrging and Shearing. In order to control this ALFONS in action (1) 4

5 Partners inspect ALFONS in Leipzig system, a control unit was developed which allows the input of information and uses other marginal information to generate a control and report data record of the weld. The data record can be saved or made available to other users via internet to a database (still to be created). In addition to the work steps realized by the main ALFONS module, a further system named GRIMLI was developed which as a module is added to ALFONS and automatically grinds the weld. GRIMLI stands for GRInding, Milling und Linishing. A further protoype was also realized for the selective and accelerated cooling of the weld using sprayed on water. Q: The first protoype has now been contructed. What tests have taken place? A: At present within WP 2, ALFONS is being used to carry out welding processes in our welding laboratory. These serve to gain experience with ALFONS and carry out the first parameter studies to improve the forging process. In further tests welds for subsequent static and dynamic tests such as 3-point bending tests or pulsation are planned which will then be analyzed by other project participants. Q: The prototype equipment also contains automatic control equipment for enhanced cooling and additional forging of the weld. How do these work? A: The system for the accelerated cooling is positioned after the welding process above the weld and then sprays the weld with a cloud of spray consisting of water and air. The use of the automated system enables the setting of the flow rate. The accelerated cooling, however, must be matched to the rail steel to be cooled due to the fact that a radical cooling down can lead to a martensitic structure. Correct application can shorten the waiting time to the final grinding process and with the welding of bainitic steels can contribute to a selective cooling to realize the required structure. Using ALFONS the weld can be compressed during the welding process or after 5

6 solidification has taken place, whereby a transformation of the cast thermite steel takes place. This can be set and monitored via the ALFONS control panel. On the control panel it is possible to set different parameters including the forging force, forging path or time of the forging. Sensors on the hydraulic cylinders record the resulting forces and paths. The control panel can record these parameters during the testing process so that they are available for further analysis. Q: One of the practical major issues faced by welding teams is the quality control of finished welds. The new system has integrated process quality monitoring and a webbased data management system. What information is provided and how will this help welders? A: In WP 2 a database is ultimately planned for the provision of the weld parameters and saving of process data. This information is to be made available via the internet. The development in WP 2 should verify the technical feasibility of such a system. It is planned that the welder will scan the barcode on the Thermite portion to enable the system to obtain information relating to the portion from the internet and that this information in combination with further input of the marginal conditions will allow the system to provide the appropriate welding recommendations to the welder. During the welding the process, the system ALFONS in action (2) records the parameters and these can be saved to a database with a clear weld identification. Subsequently all the data connected to the weld such as geometrical data from position measurements or grinding, etc. can be recorded in a type of sequence record of the welding process and can also be recorded in a database and analyzed. Q: When would you think that a final commercial system may be available and what risks will you need to overcome before this will be possible? 6

7 It has to be considered that all the systems mentioned concern prototypes and functional samples which are currently being developed in the laboratory and are also only tested there. Numerous technical challenges have to be clarified with corresponding practical solutions before a commercial application can be made available. Depending on the market requirements, estimated costs and potential user benefits, it is expected that only individual technologies will be commercially realized after completition of the WRIST project, that means in 2018 at the earliest. The weld finishing tool used with ALFONS (Module 1) Q: What type of savings do you envisage that a commercial system would bring in terms of saved time and costs? A: Almost all of the technologies to be realized in the project in connection with aluminothermic welding are designed to reduce the influence of humans and create better documentation. It is to be expected that the realization will increase the consistent quality of the welds and that the costs for reworking and complaints will be reduced. Depending on the work organization, in a number of countries time saving is conceivable through the application of accelerated cooling. On the other hand, however, the increase in investment costs for such a mechanized/automated welding process would also have to be taken into account. Q: How has the funding through the H2020 project helped make this development possible? A: The funds made available through the H2020 project enable the realization of basic tehnological tests which due to financial reasons would otherwise not have been carried out. Furthermore, such projects facilitate the networking between universities and the private sector. 7

8 WP3 - Further development of the new orbital friction welding method All the components for the mechanism have been designed as individual components by specialists to deliver the performance as required in accordance with the analysis of the integrated design. The components are currently in the process of being machined and checked prior to assembly and testing as a mechanism core system before being integrated into the gearbox, where again the overall assembly will be tested as a whole to ensure effective integration. The machine has been designed to be capable of generating the parameters necessary to achieve an orbital friction weld over the cross-sectional area of a UIC 60 rail with an interface normal stress of 100 N/mm2 and a tangential velocity of 1m/s. The first testing of the final machine will be taking place in March 2017 and a report and images will be available in the next newsletter. WP4 - Finite-element modelling of the welding processes Finite Element (FE) models have been created for the two welding processes (orbital friction / aluminothermic). For the orbital friction welding (OFW) modelling thermal and mechanical models have been set up in ABAQUS. The process includes three modelling steps: welding, forging and cooling. Equipment set up, process parameters and (partly) material data for the R260 grade were obtained and a qualitative study of heat generation models, in particular models for the friction coefficient μ have been carried out. A material model for R260 grade with temperature dependent properties and effects of phase transformations has also been developed. Initial FE-calculations on OFW of a bar with square cross section demonstrates that it is possible to capture the large deformations present during the forging phase. It was also found that the desired microstructure can be obtained using anticipated values for process parameters. The numerical FE-model for aluminothermite welding (ATW) has been developed and verified against measured temperatures in a rail during preheating and welding. Material data for R260 grade, temperature dependent thermal and mechanical properties and CCTdiagrams have been collected and a material model for R260 grade with temperature dependent properties and effects of phase transformations established. For more information about WRIST please visit our website or subscribe to latest news and updates by sending an to sympa@eurtd.com with the subject 'subscribe wrist_list@eurtd.com' 8 WRIST has received funding from the European Union's Horizon 2020 research and innovation programme under agreement No