Effects of several casting parameters on slag entrapment in mould( part A: water modeling)

The mechanism of slag entrapment in the mould was analyzed and the water modeling experiment was done according to the industrial manufacturing. The results show that the flow of the liquid steel becomes more active and the level fluctuation in the mould becomes bigger when the casting speed increases from 1.0 m/min to 1.2 m/min. So the control of slag entrapment in the mould becomes more difficult. When the depth of the nozzle increases from 30mm to 42. 5mm and the angle increases from 15~ downward to 30° downward, the level fluctuation in the mould becomes smaller and the slag entrapment in the mould also decreases. But the impact depth increases and the circumfluence vortex center moves downward, which is unfavorable for the flotation of gas bubbles and inclusions. Furthermore, the impact depth with side holes a （ 16.3 × 20mm2 ） and b （ 10 × 10 mm2 ） is almost equal, but a smaller level fluctuation can be obtained with side hole a.

Effects of several casting parameters on slag entrapment in mould (part B:numerical modeling)

Based on the effects of several casting parameters on slag entrapment in the mould （ water modeling）, the numerical modeling was researched. The results show that the flow field with a submerged nozzle section dimension of 65 mm ×80 mm is better than that with a submerged nozzle section dimension of 40 mm × 40 mm and is favorable for avoiding slag entrapment. In this paper, low surface velocity, small level fluctuation and proper impact depth can be achieved with a nozzle of an outlet angle of 25° and an immersion depth of 150 mm, or with a prototype nozzle of an outlet angle of 15° angle and an immersion depth of 150 mm.

Investigation of ductile iron casting process parameters using Taguchi approach and response surface methodology

To find the optimized levels of various casting parameters in the ductile iron casting, various casting defects and the rejection rate were observed from a medium scale foundry. The controlled values of different casting parameters such as pouring temperature, inoculation, carbon equivalent, moisture content, green compression strength, permeability and mould hardness were selected. Three different melts of metal with 0.4wt.%, 0.6wt.%, and 0.8wt.% inoculation （Fe-Si-Mg alloy and post inoculant） were produced using a 1-ton capacity coreless medium frequency induction furnace. L-27 orthogonal array with 3-level settings were chosen for the analysis. Responses for each run were observed. The signal-to-noise （S/N） ratio for each run was calculated using the Taguchi approach, and the optimized levels of different casting parameters were identified based on the SIN ratio. The analysis of variance for the casting acceptance percentage concludes that inoculation is the most significant factor affecting the castings＇ quality with a contribution percentage of 44%; an increase in inoculation results in a significant improvement in acceptance percentage of ductile iron castings. The experiment results showed that with the optimized parameters, the rejection rate was reduced from 16.98% to 6.07%.

Effects of process parameters on morphology and distribution of externally solidified crystals in microstructure of magnesium alloy die castings

During the cold-chamber high pressure die casting(HPDC) process, samples were produced to investigate the microstructure characteristics of AM60B magnesium alloy. Special attention was paid to the effects of process parameters on the morphology and distribution of externally solidified crystals(ESCs) in the microstructure of magnesium alloy die castings, such as slow shot phase plunger velocity, delay time of pouring and fast shot phase plunger velocity. On the basis of metallographic observation and quantitative statistics, it is concluded that a lower slow shot phase plunger velocity and a longer delay time of pouring both lead to an increment of the size and percentage of the ESCs, due to the fact that a longer holding time of the melt in the shot sleeve will cause a more severe loss of the superheat. The impingement of the melt flow on the ESCs is more intensive with a higher fast shot phase plunger velocity, in such case the ESCs reveal a more granular and roundish morphology and are dispersed throughout the cross section of the castings. Based on analysis of the filling and solidification processes of the melt during the HPDC process, reasonable explanations were proposed in terms of the nucleation, growth, remelting and fragmentation of the ESCs to interpret the effects of process parameters on the morphology and distribution of the ESCs in the microstructure of magnesium alloy die castings.

Recent research progress on the phase-field model of microstructural evolution during metal solidification

Solidification structure is a key aspect for understanding the mechanical performance of metal alloys,wherein composition and casting parameters considerably influence solidification and determine the unique microstructure of the alloys.By following the principle of free energy minimization,the phase-field method eliminates the need for tracking the solid/liquid phase interface and has greatly accelerated the research and development efforts geared toward optimizing metal solidification microstructures.The recent progress in the application of phasefield simulation to investigate the effect of alloy composition and casting process parameters on the solidification structure of metals is summarized in this review.The effects of several typical elements and process parameters,including carbon,boron,silicon,cooling rate,pulling speed,scanning speed,anisotropy,and gravity,on the solidification structure are discussed.The present work also addresses the future prospects of phase-field simulation and aims to facilitate the widespread applications of phase-field approaches in the simulation of microstructures during solidification.

Influence of Process Parameters and Sr Addition on the Microstructure and Casting Defects of LPDC A356 Alloy for Engine Blocks

The effects of Sr addition and pressure increase on the microstructure and casting defects of a low-pressure die cast （LPDC） AISi7Mg0.3 alloy have been studied. Metallographic and image analysis techniques have been used to quantitatively examine the microstructural changes and the amount of porosity occurring at different Sr levels and pressure parameters. The results indicate that an increase in the filling pressure induces lower heat dissipation of the liquid close to the die/core surfaces, with the formation of slightly greater dendrite arms and coarser eutectic Si particles. On the other hand, the increase in the Sr level leads to finer microstructural scale and eutectic Si. The analysed variables, within the experimental conditions, do not affect the morphology of eutectic Si particles. Higher applied pressure and Sr content generate castings with lower amount of porosiW. However, as the filling pressure increases the flow of metal inside the die cavity is more turbulent, leading to the formation of oxide films and cold shots. In the analysed range of experimental conditions, the design of experiment methodology and the analysis of variance have been used to develop statistical models that accurately predict the average size of secondary dendrite arm spacing and the amount of porosity in the low-pressure die cast AISiTMg0.3 alloy.

Research methods and influencing factors of interfacial heat transfer during sub-rapid solidification process of strip casting

Interfacial heat transfer behavior between the molten steel and twin-rolls is a key issue in the strip casting process,and it has already attracted wide attention from industrial and academic communities of steel.The research methods and influencing factors on the interfacial heat transfer were summarized.Numerical simulation models,semi-industrial scale,and laboratory equipment have been developed in this field,and these methods were also improved by worldwide researchers based on the development of computer,automatic,and visual technologies.Coating properties,naturally deposited film,and casting parameters are the main factors which affect the heat transfer significantly.Although lots of research has been carried out,the internal relations among these influencing factors,interfacial heat transfer,and the quality of the strip are still worth to be further explored.Keywords Strip casting Interfacial heat transfer Simulation method Coating property Naturally deposited film Casting parameter.