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The pouring temperature could not be too high to cause coarse grains.
It also is the reason why the grain of fig.1(a) is relatively coarse and a phase presents dendritic characteristics compare to the grain in fig.2(b).
ε-phase which distributed in the boundaries of grain and the effect of Cu on grain refinement effectively improve the strength and hardness of the material.
Therefore, with the content of Al increasing, the number of α phase gradually increased and the expansion coefficient is gradually decreased [9].
In the process of crystallization, these compounds were pushed to the dendrite and boundaries of the grain, which formed a compound of the netted and discontinuously distributed along the grain boundary to inhibit the development of dendrite and refine the organization and network.

Fig. 2 (b) shows that the heat affected zone consists of the coarse grained region, fine grained region and incomplete recrystallization region.
Therefore, the size of the HAZ is narrow and the grain size in the HAZ is relatively small.
(a) Fusion zone (b) Coarse grained region (c) Fine grained region (d) Incomplete recrystallization region Fig. 3 Microstructures of laser welded joint Hardness.
Hardness in the HAZ shows a progressive decrease in the direction from the coarse grained region to the base metal
Fig.7 (a) shows that the fracture surface of the shear area in the fusion zone is mainly composed of a considerable number of uniform equiaxed dimples that were formed by microvoid coalescence.

Non-diamond carbon has been found on the polished surfaces and polishing debris, but it has not been verified whether they formed directly from the polished diamond grain or transformed after detaching from the grain.
However, a number of non-closed irregular pores ranging from submicron to a few microns were disclosed, as shown in Fig. 1(b).
Fig. 3 A high resolution TEM image of a polished diamond grain.
Fig. 3 shows a cross-sectional image taken at the interface between the diamond grain and attached layer.
The atomic lattice of the diamond grain is clearly observable in contrast to the amorphous nature of the attached layer.

In heat resisting steels, creep cavities are formed at grain boundaries through long time use at high temperatures and stresses.
These creep cavities grow along grain boundaries, lead to grain boundary cracks by linking up each other, and cause the low ductility and premature fracture.
During the long time exposure at elevated temperatures, creep cavities nucleate and grow at grain boundary in most of the heat resisting steels.
The physical properties are the energies of and diffusivities along, both grain boundaries and creep cavity surfaces [1,2,3].
The standard 304 steel was subjected to a solution heat treatment at 1130� for 30min, whereas the modified 304 steel was heated at 1180� for 20min to arrive at grain sizes having ASTM grain number of around 5.

The figure shows that the laser melted layer can be divided into two regions: surface layer dendrites region and inner layer fine-grained region.
The coating layer hardness gradually increases from dendrites region to inner, and reach peak (HV680) at the fine-grained region.
The reason why micro hardness reach the peak at the fine-grained region is that grain size of the region is finer and distribution of the hard phase is more uniform in comparison with dendrites region.
After laser remelting, the number of micro-convex body reduces and the micro-structure is fine, surface condition is better.
(3)After laser re-melted the coating surface obtained fine grain and homogeneous microstructure.

PY – radial component of cutting force; PZ – tangential component of cutting force; PYS, PZS – specific components (per length unit of the grain cutting edge) of the total resultant R of the cutting and friction forces; PYFR – specific component of the force PY, occurring as a result of the stresses action on the blunting platform; PZFR – specific component of the cutting force PZ, occurring as a result of the friction of the grain` blunting platform on the metal.
Component force from the blunting platforms occurs due to the presence of contact pressure (refer with: Eq. 3): PYFRj=ρk∙fj; (3) ρk – contact pressure on the blunting platform, equal to ρk=Ϭi/3; fj – area of the blunting platform on the grain of the wheel.
Total area F of the blunting (refer with: Eq. 4) on the grains of the wheel is equal [5, 6, 7]: F=∑fj=η∙Fc; (4) η – degree of grinding wheel blunting, which is equal to ratio of total area of blunting platforms of all wheel grains (on its entire surface) to geometrical area of all wheel working surface, i.e. the value of η determines the relative reference surface of the wheel on the blunting platforms of the grains [8, 9].
For grinding with radial feed, the speed of metal removal (refer with: Eq. 5) is equal to [10, 11, 12]: Q=π∙dср∙n∙∆tf∙le; (5) DSf=n∙ Dtf; n – number of revolutions of the part per minute; DSf – actual axial feed, mm/min.
This model establishes a functional interrelation with cutting modes, geometric parameters of the contact area of the wheel and the part, structural behaviors of the processed material and blunting of grains of the wheel on the basis of the fundamental regularities of the mechanics of metal plastic deformation by the wheel grains in the cutting zone, kinematic regularities of abrasive grains cutting process in conditions of temperature and speed parameters at grinding on circular grinding machines.

The solution-treated specimen had an equiaxed grain structure, and many second-phase particles can be observed near the grain boundaries.
This indicates that the crystal grain size slightly coarsened as the solution heat treatment temperature increased.
In the cold-rolled specimen, the crystal grain microstructure was elongated in the rolling direction.
The grain boundaries were not straight but wavy, and shear bands can also be observed.
The second phase particles were mostly aligned in the rolling direction and were located near the grain boundaries.

It has been shown that ultrafine-grained and nanostructured materials with unique properties can be obtained in the processes of equal-angular pressing in some combined and combined processes of metal working with pressure, characterized by intensive alternating deformation.
The number of passes and reduction schedules were calculated in order for production of breakdown bar at thickness HP = 65mm for finish rolling.
The rolling of workpiece with the use of offered method will allow to reduce the number of rough passes from eleven to seven and increase summary degree of strain in plane of slab symmetry by 1.15-1.2 times (fig. 2).
Coarse-grained structure of the ingot causes necessity of the all-around hammering usage to reach the considerable forging grade (summary degree of strain).
Raab, Deformation methods for obtaining and processing ultrafine-grained and nanostructured materials, Ufa: Guillem.

Further implementation and improvement of existing process, including weld quality and time improvement, electrode life extension, maintenance cost reduction and development of new techniques for resistance spot welding, will greatly impact the above noted industries due to the large numbers of spot welds they perform in their manufacturing processes [3,4].
The continuous forwards movement of the process tape results in an uninterrupted process producing constant quality over a number of shifts.
The base material of H220PD consists of a fine-grained ferrite-perlite structure.
The microstructure of the TRIP steel base material consists of a fine-grained multi-phase structure with dominant ferrite component, bainite and retained austenite segregated on boundaries of ferrite grains.
The microstructure of weld metal consists of mostly fine-grained martensite arranged in typical lamellar formations.

Introduction Wheat milling is not simply mechanical grinds of wheat into flour, but separates cortex and embryo of wheat grain, then mill embryo into powder, meanwhile ensure wheat bran is not too fragmented[1,2].
The influence of wheat grain powder size on roller wear were studied by the analysis of the weight loss and wear surface microstructure of samples, and the wearing mechanism was discussed.
The abrasive was “XIHAN” wheat grain, dried in natural condition, ground by WK-200B high-speed grinder, separated to five sampls with the size of 0.5, 1.0, 1.5, 2.0 and 2.5 mm of wheat powder by standard test sieve (national standard GB/T6003.1-1997).
A large number of fine flour particles had a grinding and mechanical polishing effect on the surface of sample metal[9].
As a result, the number of furrows was decreased, with more and more shallow depth, and wear surface tended to be smoother.