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Since for a long time, Cr12 steel is the main materials to be used for cold work dies in the word and a large number of researches have carried out in decades [1-3].
It is clear that there is large number of fine carbides precipitated in the matrix and distributed uniformly in new steel comparing with Cr12MoV steel.
However, the grain growth too large is not beneficial for the mechanical properties if the austenized temperature is higher.
As is known, too low quenching temperature results in austenitizing inadequate, the high tends to cause the coarse grains.
Acknowledgements The authors acknowledge the project for finance support (Project Number:KKSY201251113).

Since there are no grain boundaries, the nickel-base single crystal superalloys eliminate the void-damages localized at grain boundaries.
In particular, the DWT provides a sparse time-frequency representation of the original signal (the wavelet coefficients) that has the same number of samples as the original signal.
[2]John Sadowsky: johns hopkins apl technical digest, volume 17, number 3 (1996), p. 258-269
[5]Jesu’s Pando: The American Physical Society, 1998, volume 57, number 3, p. 3593-3601

Experiments shows when oxygen content is higher than 2.85%, hafnium has bad plasticity, incident to brittle fracture; Appropriate alloy elements, such as Zr, Nb, could improve the plasticity of hafnium pipes; Fe, Si elements can refine grain and enhance intensity.
Otherwise, to get small grain size and low oxygen content could be done through hot rolled deformed reinforcing.
Table 2 Test result of mechanical property for hafnium plate Serial number annealing Test temperature [℃] Tensile strength [Mpa] Yield strength [Mpa] extensibility 1 M,750˚C，1h Room temperature 335 166 45％ 2 M,720˚C，1h Room temperature 340 235 43％ 4 M,600˚C，1h Room temperature 405 189 36％ 5 M,500˚C，1h Room temperature 464 243 31％ 6 M,450˚C，1h Room temperature 450 260 37％ 7 Un-annealed Room temperature 530 385 15％ ASTM Standard Room temperature 400 151 20％ Impact Toughness Three samples are got from rolled hafnium plates to carry out impact experiments.
Table 3 Result of shock testing for hafnium plate Serial number Tests condition Unit impact toughness[J/cm2] 1 Room temperature 63.9 2 Room temperature 65.6 3 100˚C 76.5 4 100˚C 73.8 Corrosion-resistance Performance Hafnium has good corrosion resistance, slightly soluble in aqua regia and relatively steady in inorganic acid, such as bromic acid, iodic acid, perchloric acid, phosphoric acid.
Table 4 Result of corrosion test for hafnium plate Serial number Weight put on [mg/dm2] Samples surface Before tests After tests 1# 5.75 White bright Interference colour 2# 6.79 White bright Interference colour 3# 5.84 White bright Interference colour ASTM 10 White bright Interference colour Physical Characteristics Tests As to operation conditions of control rods in the reactor, the linear expansion coefficient, the thermal conductivity, Pisson ratio and the modulus of elasticity need measurement to perform calculation.

Table 2 Purification program of AZ61magnesium alloy Experiment number Experiment program 01 Blow Ar flow 0.5 L/min 02 Blow Ar flow 1.0 L/min 03 Blow Ar flow 1.5 L/min 04 Under no conduction Experimental procedure Preheating the tilting type heating furnace to 400~500℃, and then passing into sufficient Ar to exclude air in the crucible, after that, charging the preheated magnesium ingot, and closing the lid, at the same time, passing into the combined protective gas, after the magnesium ingot is completely melted, continue to heat up to 680℃ and adding the preheated Al and Zn ingot, stirring the melt for 3~5min to uniform the composition and temperature after the charge melting down, then passing into Ar to deal with the melt for 10 min according to Table 2 after raising the temperature to 720℃, after that , pouring the melt into the preheated mold.
Inclusion Inclusion content is calculated by are the ratio method. 2 1 4 3 Fig. 1 Casting metallography A B Fig. 2 SEM photos and energy spectrum of inclusion in alloy Table 3 Elemental components of point A in Fig. 2 Element O Mg Al Zn Cl Weight percent（%） 43.84 50.86 4.10 0.44 0.76 Table 4 Inclusion content of experimental alloys Experiment number 01 02 03 04 Content（%） 0.73 0.58 0.84 1.37 From Table 4, it can be seen that blowing Ar is obvious effective on inclusion removing, Ar agitation can promote inclusion gathered to grow up, which is good for the inclusion to sink to the bottom of the melt in the static setting, and Ar can adhere small particle inclusions when it escapes from the melt.
Table 5 Mechanical properties of normal temperature Number Not annealed Annealing 60s Annealing 1h σb(MPa) σs(MPa) δ(%) σb(MPa) σs(MPa) δ(%) σb(MPa) σs(MPa) δ(%) 01 329.93 238.12 5.10 347.81 218.09 11.64 329.66 170.86 16.01 02 336.36 235.51 7.09 352.51 196.76 17.05 312.37 151.29 19.14 03 328.47 239.20 3.82 320.75 216.82 5.82 326.38 170.40 13.81 04 335.18 229.38 4.02 321.39 190.74 9.77 332.88 171.57 15.81 Note: σb is tensile strength, σs is yield strength, and δ is elongation.
The Combined Effects of Electromagnetic Stirring and A1-5C Master Alloy on Grain Refinement of AZ31 Magnesium Alloy[J].
Effect of Ultrasonic Power on Grain Refinement and Purification Processing of AZ80 Alloy by Ultrasonic Treatment[J].

Fig.1 The micro-Raman spectra of the samples annealed at 750℃, 800℃,850℃,900℃,940℃,990℃for 2min by RTA The experiment showed there exist discrete quantum states in the connection between the grain size and the temperature.
The experiment showed the grain size at 850°C is the biggest on a glass substrate.
The transitions between quantum states with different quantum numbers should be forced by the certain energies corresponding to the proper temperatures.
The transitions between quantum states with different quantum numbers should forced by the certain energies corresponding to the proper conditions.
where J is the rotational angular momentum quantum number and I is the moment of inertia.

If the partial pressure of N2 increases, the collision between particles becomes more, the direct sputtering substrate single-phase drop will decrease; at the same time as the unit space within the particle number increased, second sputtering may occur to reduce the grain size of surface film.
With the increase of nitrogen partial pressure, the number and size of the droplets on the film surface decrease, the number of pinhole in the film is reduced, film is dense, and the grain is fine.

Crystalline phases are identified according to the dates of ICDD powder diffraction file (PDF): card number #06-0696 for Fe (110) and card number #38-1397 for FeSi (210).
However, from the SEM observation of Fig.2, the surface of the film has been crystalline after anneal at 1073 K for 2 hours and formed island-like grains and the EDS measurement indicates that the composition of grains is Fe/Si≈1, so the formation of FeSi could be clarified.
Crystalline phases are identified by PDF: card number #38-1397 for FeSi(210) and for FeSi(310).

The initial grain size was 100 µm.
(a) (b) Figure 1 (a) EBSP map of section number 3.
Simple line-scans along different sample directions plotting the number of pixels belonging to nuclei on that line versus the position would result in an ideally uniform distribution in all directions if the nuclei were randomly distributed (provided that enough nuclei are sampled to avoid significant statistical effects).
(a) (b) Figure 3 (a) Line scan frequency map along ND for section number 3.
The aspect ratio of the individual grains will typically be high if there is preferential impingement in 1 or 2 directions.

In the casting area, there are many researches in degassing[1], removal of inclusions[2], reducing segregation[3], especially in grain refinement[4].
However, these researches show that the attenuation of ultrasound in the melt of metals is significant and the working range of grain refinement is limited.
These two models are as follows, (1) Flow model: Standard k-epsilon Model (1) (2) Where, is the density, is the velocity, is the viscosity, is the turbulence kinetic energy, is the rate of dissipation, is the generation of turbulence kinetic energy due to the mean velocity gradients, , is the generation of turbulence kinetic energy due to buoyancy, , is the contribution of the fluctuating dilatation in compressible turbulence to the overall dissipation rate, , and are user-defined source terms, and are the turbulent Prandtl numbers for and , , and are constants.
With the nucleation site volume fraction decreasing, the distance between the bubble layer and the free end of amplitude transformer become farther and the number of cavitation bubbles become lower, because both the attenuation coefficient and the volume of the bubble layer change.
As a result, when the cavitation happens, the number of cavitation bubbles is higher, which means more bubbles will gather together and the bubble layer will become more difficult to be pushed away by the pressure from ultrasound.

Over the past few years, the grain size of hard alloy decreased more than fivefold.
Work surface requirements (Fig. 3): · geometric dimensional accuracy: Ø80–0,05 mm, Ø28–0,03 mm; · basic surface roughness Ra = 0.7…0.8 μm; · maximum roundness accuracy error ○ 0,005 mm; · maximum linearity error — 0.005 mm; · work surface hardness HRC 42…48 (after hard-surfacing with HFC); · work material: high-duty cast iron with globular graphite Gh75-50-03 (numbers represent the following breaking point, yield point, modulus of elongation).
Durability L (in meters of the treated surface) was calculated by the formula: (1) d - feedstock diameter, mm; n – number of rounds during processing, K – the number of machined parts.
Despite the fact that the alloy VK6 is currently still widely used is promising applications of superhard alloys for processing (such as nano cubic boron nitride) or fine-grained hard metal (such as N10G) simultaneously with modern types of coatings.