VALVE DESIGN
Sample model image
Hot spot images after solidification
that did not adversely affect product quality in accordance with the standard requirements .
Casting method development studies
Casting simulations have been conducted to prevent defects such as shrinkage and gas porosity , as well as negative effects like internal stresses , in the body and bonnet parts to be produced using sand casting methods . In addition to these simulations , feeder and feeder distance calculations were completed to maintain a productive Net / Brute ratio and ensure high-quality casting . Solidification gradients and molten steel filling simulations were performed using Novacast . Feeder and runner designs were optimised based on these simulations , leading to the development of an optimal casting method . Improvements were made to the design based on casting simulations to ensure directional solidification and minimise the likelihood of hot spots . All simulation work was meticulously documented and included in the design package .
Images after NDT studies
Additionally , casting method forms were created and documented to define feeders , sand mixtures and cooling systems , aiming to prevent confusion during the production phase . The goal of these efforts is to achieve high-quality production with low scrap rates using the developed model and casting method . Prior to the casting simulation and calculation studies , hot spots and shrinkage cavities were observed in the regions indicated in the visuals of the cast parts . Non-Destructive Testing ( NDT ) was performed on the cast parts before the simulation , and the discrepancies identified in the simulation were concretely detected . Shrinkage cavities occurred in areas distant from feeders and where the module height was high . Additionally , due to turbulence during the filling of the mould , gas cavities were observed at various points on the parts . All these discontinuities were detected through liquid penetrant tests and radiographic inspections performed as part of the NDT work . The relevant areas of the parts were sectioned to confirm these discrepancies . Below , images of the
parts , which were examined using carbonelectron microscopy after the NDT tests , are shared . As a result of the NDT and simulation studies , new model data were generated , addressing issues such as directional solidification that could create defects . Following the creation of the new data , errors such as shrinkage and gas cavities in the cast parts were resolved .
Testing and validation process
After completing the casting , machining and assembly phases , the valves must be tested to ensure they meet the relevant standard requirements . According to the API6D design standard requirements , valves must undergo pressure and leak tests . The prototype valves developed successfully passed pressure and leak tests conducted at 1.5 times the working pressure ( 19.6 Bar ), which is approximately 29.4 ~ 30 Bar . The theoretically calculated opening and closing torque values were also measured and verified during the design calculation phase . In addition to the tests performed on the valve itself , tensile tests , chemical analyses , hardness tests and other tests were conducted on the subcomponents used in the valve assembly to ensure that all standard requirements were met .
Conclusion
This study aimed to explain the contributions of advanced computer-aided engineering applications and the positive effects of modern product development processes , in addition to traditional product development techniques . Design and casting method calculations were validated using simulation programs to create the most suitable design and production method . Data obtained from calculations and simulations were concretely tested and validated after prototype production . As a result of these efforts , high-quality and long-lasting API6D ball valves have been developed , fully meeting standards , market and customer requirements .
www . valve-world . net Valve World October 2024
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