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The ferrite grain sizes were measured through the comparison method described in UNI 3245.
The examined steels exhibit homogeneous fine-grained ferritic microstructures which were characterized by the ASTM grain size number (Table 2).
The ferrite grain sizes in the microalloyed steels with simultaneous presence of Nb and V are slightly finer than the ones belonging to the other studied steels.
The final coiling temperature seems not to have significant effects on the ferrite grain size, except for the mild steel grade.
Table 2 - ASTM grain size number of the investigated steel sheets. 1 2 3 4 5 6 7 8 9 10 11 12 ASTM Grain Size Nr. 10 10 9 10 10 10 10 10 10 >10 10 >10 Mechanical Properties of the Steels.

However, it has to be pointed out that the wave propagation in granular system can be quite complicated due to the interaction between grains, especially when some grains are damaged and fractured.
Apart from the abovementioned problems, many people are curious about the relevant problems such as how impact-induced stress wave will result in failure in a multi-grain system, which grain will experience the largest tension stress and is thus prone to damage and what kind of failure patterns granular media will form under high strain rate impact.
Studying the response of a chain of spheres under impact loading can be a simple and effective way to address the multi-grain system problem.
Fig. 3 The evolution of damage in the brittle bead chain under impact velocity of 10 m/s with the initial damage threshold of 62.5 Pa1/2 and the fracture energy of 2.6 J/m2 (Case 3) The total weighted damage in each brittle bead, bead damage, is plotted in Fig. 4 and is defined by: (4) where is the total number of material points in each bead and  is the bead number, from 1 to 10.
Fig. 5 The damage in the third bead with different fracture energies Conclusion A rate-dependent elasto-damage model is applied to simulate how brittle grain chain fails under high velocity impact.

The importance of aluminum lithium alloys are derived from the fact that a large number of investigations have been carried out in USA, UK and France in last 10-15 years.
A small amount of zirconium is added for grain size control and retarding recrystallization.
Equilibrium phase δ (AlLi) forms mainly at grain boundaries [23] and can lead to void nucleation and intergranular fracture [24].
The fine β' particles act to pin grain boundary movement, thereby resisting grain growth [25]. β' particles also act as preferential nucleation sites for δ'.
With over-aging, the T2 phase starts to nucleate at grain boundaries.

A good uniformity and corrosion resistance of zinc (tin) layer can be obtained by adding grains, no inclusion of zinc (tin) tablets to supplement the zinc (tin) ion in the bath.
Therefore, new or renovated electroplating zinc (tin) production line all over the world is adapting the method by adding the majority of zinc (tin) to add grain to replace the previous zinc (tin) tablets ways to add zinc the bath (tin) ion.
Zhang Jianpei et al [2] introduced a grain of tinplate tin plating preparation method, the metal tin ingots after melting, drip through a gate into cans, tin liquid by mouth or infusion drops condensing the bath, cooling bath that has the oil, water, cooling liquid layer, melted tin solution is first instilled the upper oil bath, and then into the lower cooling water bath made of granulated tin grain coagulation.
The shortening of the ingot melting will help to reduce and prevent the oxidation of molten metal, and to reduce the number of metal oxide melt inclusions, and to obtain the not slag of the metal particles.
Chinese invention patent: 03114561.2, open number: CN1438085, 2003.03.21

A study on electron beam melted Ti-6Al-4V reported by Foramnoir [16] reveals that the highly anisotropic columnar grains are along building orientation.
Cain [4] thought the columnar grain structure was a result of the epitaxial growth caused by the successive layer deposition.
It is distinct that the microstructure of SLM Ti-6Al-4V is characterized by predominantly columnar grains, which are near-parallel to the building direction.
This columnar grain structure is the result of sustained cooling rates experienced by previously deposited layers during manufacturing.
The S-N plots of maximum stress vs. log number of cycles to failure of the SLM Ti-6Al-4V specimens in different building-directions are shown in Fig. 4.

Before annealing, in addition to Feα peaks, we notice a number of Cr pecks of the film (Fig. 1. a).
Where the annealing is happened during the annealing at 600 °C, the formed grain grew gradually and take the mid-size equal 25 µm (fig. 2. b).
The increase of temperature and extend of annealing led to a development of islets and a remarkable diminution in its number.
The clear region is the places which pointed both sides of grain boundary in contrast; the dark region pointed the location of grain’s remains.
The same of the results are remarked by punctual faults has depart the apparition of   grains boundaries [4].  

The results showed that: between the coating and the substrate is metallurgical bonded; The microstructure of coating layer was compact actinomorphous structure with plentiful nubby and strip eutectics; Actinomorphous structure was mixed structure of martensite and γ alloy solid solution covered with a large number floriform and dendrite eutectic; The coating has high hardness and good wear resistance.
From figure 1 can be seen, cladding coating is divided into three areas: coating, substrate and binding layer.The combination of coating and substrate for the metallurgical bonding.White band is a mixture with the cladding metal and the base metal, it is plane austenite grain along heat flow direction low-speed epitaxial growth, and keep straight interface with the heat affected zone.
Due to the binding layer is plane austenite grain, there is no eutectic, carbides and borides precipitation, the microstructure constituted by the solid solution, the hardness is lower.
(3) Phase analysis showed that: Actinomorphous structure was mixed structure of martensite and γ alloy solid solution covered with a large number floriform and dendrite eutectic

Though number of alloying elements have been imparted in this steel to stabilize the microstructure for high temperature application [1], the alteration in microstructure is inevitable due to the contribution of time dependent damage mechanisms.
A large number of data have been generated on the resultant mechanical properties including that of creep and low cycle fatigue behavior of these steels [2-7].
The average initial grain size was measured and found to be 35 μm.
Precipitation of chromium and molybdenum carbides at grain boundaries is clearly evident in these figures.
Present investigation indicated that in 2.25Cr-1Mo steel as the ageing temperature or time is increased, molybdenum and chromium carbides get precipitated in the sequence of M3C, M7C3, M23C6 and M6C at the grain boundaries and within the grains.

It is found that the larger and more uniform the grains of the phosphor, the higher the emission efficiency.
Chromaticity coordinates and relative brightness of LBE with phosphors Phosphor sample number Chromaticity coordinates of LBE with phosphor Relative phosphor brightness, [%] No.1 x = 0.284 y = 0.319 86.2 No.2 x = 0.299 y = 0.344 88.5 No.3 x = 0.298 y = 0.343 75.6 No.4 x = 0.284 y = 0.315 91 No.5 x = 0.305 y = 0.344 100 The emission chromaticity coordinates of LBE with filled phosphor correspond to white color.
It is found that the larger and more uniform phosphor grains are, the higher emission efficiency is.

It is found that in a large number of engineering applications, single metal and alloy brush plating do not present ideal tribological properties [12-15].
The narrower the peak is, the larger the grains are.
The addition of PTFE can remarkably refine coating grains.
Conclusion Grains are refined significantly in PTFE coatings.
The 10g/L PTFE coating has the minimum grains and the maximum microhardness.