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The grain size of sample processed by multi-pass ECAE was reduced with the extrusion number.
The EP shifts to more positive values with increasing the ECAE pass number until four-pass.
It is noted that the grain size of multi-pass ECAE samples decreases with the ECAE pass number.
Effect of the number of ECAP pass time on the electrochemical properties of 1050 Al alloys.
Corrosion resistance of ultra fine-grained Ti.

Performance analysis of feeding device of port pneumatic grain unloader in CFD GUO Liwei1, a, LIU Bo2,b 1, 2 College of mechanism and electron engineering, Central South University, Changsha ,Hunan ,China 410075 alevisguo@qq.com, b liuboyh@126.com, Keywords: CFD; Port pneumatic grain unloader; Feeding nozzle; Secondary air.
Feeding noozle of port pneumatic grain unloader is vital to the whole system, CFD is used to simulate the flow field and optimize the geometry of the vacuum nozzle.
Vacuum nozzle is one of the largest power consumption device components of the port pneumatic grain unloader, the resulting pressure loss account for 1 /3 of the entire system.
There are mainly two types of feeding nozzle in the vacuum device, single tube nozzle which is generally used on small grain suction machine, and large, multi-use twin tube suction nozzle used on medium-grain suction machine.
Numerical simulation of nozzle flow field analysis based on CFD software is a fast, intuitive design approach can significantly improve the efficiency and accuracy of the test study, shorten product development cycles and reduce the number of product trial.

The influence of the number of passes and the type of processing routes (A or C) on the mechanical properties of Armco Iron after ECAP processing is presented in Fig. 2 [3].
This grain size is usually obtained after a few passes and is a result of the equilibrium between grain refinement and grain growth.
Thin sheets with just one or few crystal grains in thickness direction exhibit material flowing difficulties compared to sheets with many grains.
Smaller crystal grains have fewer atoms inside the grain compared to bigger grains and therefore have more surface atoms.
(a) Cylinders machined from the samples upset in various numbers of passes (b) Cracked cylinder specimen machined from the sample upset in eight passes [14] The results of the study showed that material formability was kept high even after a high number of SPD upsetting passes (Fig. 5).

By this method, the material grain size can be refined to 20~200nm, which are nanometer level.
Fig. 5(a) is a line chart of the effective strain of these seven points when the number of torsion is 0.5, 1, 1.5 and 2.
The grain gets finer and more homogeneous when the number of turns increases [7].
This is the reason for the central area owns a larger grain size but edge area owns a smaller one.
This inhomogeneity gets smaller, and the strain increases with the number of turns increases which get the grain refined.

So the multi-pass equal channel angular pressing can achieve good effect of grain refinement and improves the distribution uniformity of grain-size.
The extrusion material is industrial pure aluminum, the diameter of specimen is 30mm, the length of specimen is 260mm, the number of meshing elements is 41490, and the extrusion temperature is 20℃.
This shows that: the extrusions can achieve the effect of grain refinement owing to a strong shear stress in the direction of inside corners of the mold, while uniform distribution of the grains only can be obtained after multi-pass ECAP
The results can confirm that the multi-pass ECAP can effectively achieve the effect of grain refinement, and increases the distribution uniformity of grain.
Acknowledgements This work was financially supported by the Guangxi Natural Science Foundation (Gui Ke Qing: 0832006) and the open foundation of the key laboratory of new processing technology for nonferrous metals and materials, Ministry of Education, Guangxi University (Contract Number: GXKFJ-17).

Grain boundary is defined as in different number of grain orientation between two adjacent grid points.
When the grain orientation of two adjacent points at the same time, the number of phase can be thought of as the adjacent lattice as part of the same grain.
The number of conventional grain-oriented is 32 or 64.
If the number is infinite, there will be a very large amount of calculation, the cost of calculation will be very high.
In front of the MC simulation time step, the average grain size increases quickly with the increases of the simulation time step, number of grain declined sharply with the increase of time step.

It can improve the combining strength among the grains interface, and makes every grain effective during the drilling.
Within the end of drilling process, the drilling spindle direction force decreases along with an increase of the number of drilling holes. 47 36 64 496 485 502 0 100 200 300 400 500 600 Electroplated BrazedDrilling hole number 0 50 100 150 200 250 0 100 200 300 400 500 Drilling hole number Drilling force( N) Electroplated core drill Brazed core drill Fig.4 Tool life of thin-walled electroplated Fig.5 Comparison of the values of forces and brazed core drill 0 50 100 250 350 500 (Numbers mean the drilling hole number) Fig.6 Wear process of brazed diamond grains The observations on tool life and drilling spindle direction force can been better understood if one observes diamond grit fail process during drilling shown in Fig.6 and Fig.7.
For a smaller number and sharper blade of real working diamond grains on the commencement of drilling process, drilling spindle direction forces of thin-walled monolayer brazed diamond core drill and electroplated core drill are the same and smaller.
The thin-walled monolayer brazed diamond core drill has super-excellent machining performance only with a smaller number of diamond grains. 3.
No pulling out and smaller number for the brazed diamond grains are two key factors of longer life and higher machining efficiency of the thin-walled monolayer brazed diamond core drill.

The size effect occur in thin metal foils because of low number of grain.
The surface roughening in coarse grain, increased higher than in fine grain.
The inhomogeneous grain strength in coarse grain is higher than fine grain in SUS 304 thin metal foil.
Conclusion In SUS 304 thin metal foil, the Ra increases higher for coarse grain than fine grain, because of the lower slip band intersection in coarse grain that affect to lower MPT in coarse grain, compared to fine grain.
In SUS 316 thin metal foil, the Ra increase higher for coarse grain compared to fine grain, because of GMO lower in coarse grain compared to fine grain that affect to more inhomogeneous grain strength in coarse grain compared to fine grain.

The number and length of side crack increased with increasing Ca content.
As can be seen in the figure, the number and length of side crack increased with Ca addition.
On the other hand, the number and length of side crack increased with decreasing the preheating temperature and increasing the reduction ratio per pass.
Conclusion The number and length of side crack increased with increase Ca content.
The hot-rolled AZ31-xCa sheets had the equiaxed grains measured to 4∼8µm in average grain size.

Fig.4 shows clearly the abrupt increase of visible ferrite grain number via time due to straining.
However, even a small strain can lead to an increase of ferrite grain number and decrease of ferrite grain size (Fig.5b).
Due to the very limited un-transformed region or strong recovery of ferrite the ferrite grain number can not increase significantly.
However, the dynamic recrystallization of ferrite may lead to an apparent increase of ferrite grain number and further reduction of grain size.
Note that in spite of these two unfavorite factors for ferrite nucleation the dynamic recrystallization of ferrite may contribute to a higher grain number.