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It should be noted that threaded gears used in metrological instruments and a number of other critical structures are involved in the measurement process or in movements that require high accuracy only by touching one side of the profile.
Reducing it allows you to reduce the number of passes, maintaining and even somewhat “softening” the grinding conditions.
A gear made of steel 12ХН3А was chosen as the object of study: number of teeth z = 32, tooth length l = 45 mm, module m = 5 mm (Fig. 1).
According to the results obtained, the improved technology for grinding teeth with copying provides the necessary accuracy, despite the reduction in the number of working passes, while reducing the main technological time by ≈20 %.
Analysis of grinding mechanics and improved grinding force model based on randomized grain geometric characteristics.

The number of components manufactured in this way is continuously increasing.
A fully martensitic and fine-grained microstructure was obtained for all processes.

., specific gravity, grain size, Atterberg limits, compaction characteristics, permeability coefficient, shear strength parameters and consolidation parameters.
Table 1: Typical Chemical Composition of Fly Ash Contents Percentage by Mass Calcium oxide, CaO 0.37 Silicon dioxide, SiO2 27.88 Aluminium oxide, Al2O 5.23 Iron oxide, Fe2O3 1.21 Magnesium oxide, MgO 0.42 Sulphur Trioxide, SO3 0.04 Sodium carbonate, Na2O 0.20 Potassium oxide, K2O 0.64 Titanium dioxide, TiO2 0.24 Other alkaline & unidentified 4.0 LOI (Loss on Ignition) 0.21-28.37 Table 2: Physical Propeties of Fly Ash Parameters Flyash Density 2.17 g/cm3 Bulk density 1.26 g/cm3 Moisture content 2% Particle shape Spherical/Irregular Colour Grey pH 6.0-10.0 Specific gravity 1.66-2.55 Grain size distribution Sandy silt to silty loam Porosity 45%-55% Water holding capacity 45%-60% Electrical conductivity (dS/m) 0.15-0.45 Geopolymer concrete Fly ash based Geopolymer concrete is an innovation material for the construction as it is freefrom hydration process, alakli and aggregate reaction and found highly durable in aggressiveenvironment.
In order to achieve the required thickness, a number of laminates are used (Fig. 9).

The required grain fineness, phase composition and, accordingly, high strength properties are traditionally achieved by energy-intensive sequential performing of hot-working schedule at the preliminary and final stages, as well as by heat treatment (quenching + tempering (Q&T) and normalization) [21-23].
Improving their accuracy requires consideration of many factors (which is difficult), and as the number of such factors increases, the speed decreases.
Strengthening Effect of Nb on Ferrite Grain Boundary in X70 Pipeline Steel.

In the future, a short boriding time in case of HFC heating application may suggest the use of this method of boriding at production lines for mass serial production with large numbers of parts to be hardened per shift.
Major characteristics of boride coatings obtained on 65G steel using high-speed HFC heating Composition Boriding Agent main faction particle diameter, µm Coating thickness, µm Microhardness HV100, MPa Coating/base interface state 1 75 340 15332 diffuse 1 150 320 13315 expressed 1 315 290 12057 expressed 2 75 360 7817 absent 2 150 600 9194 absent 2 315 350 13778 presence of interlayer 3 315 195 10970 presence of interlayer 5 - 675 26275 expressed 6 - 80 11678 expressed 7 - 110 8464 diffuse 8 - 800 20117 diffuse 4 75 20 4826 absent 4 150 30 4204 discontinuity 4 315 400 10325 discontinuity As can be seen from Fig. 1.a, when using a composition consisting of boron carbide with fraction size of not exceeding 75 μm at a ratio of 92% by weight and P-0.66 flux at a ratio of 8% by weight, the formation of a boride coating with a fine-grained ledeburite-like iron-boride eutectic structure is observed.
However, unlike other coatings in the form of an iron-boride eutectic with closed carbide regions, the grain size of these eutectics is much larger, and the microhardness of this coating is also much higher, which indicates the formation of a structure of a different type.

A number of authors have performed research related to increase the material removal rate (MRR) and to reduce the electrode wear ratio (EWR) such as Valentinĉiĉ et al [3] and Ferreira [4] who studied the micro machining with copper tungsten electrode and the effect of different parameters such as tension, current of discharge, impulse time and dielectric pressure on the variation of the surface aspect by examining its topography and its microstructure with an electrons scanner.
Moreover, in the immediate vicinity of the molten metal, the heated areas at very high temperature undergo an enlargement of the grains and sometimes a local fusion of the grains joints which causes the formation of particular structures components.

In order to use reasonably the macro parameter (Eq. 9) to describe the fatigue growth, the optimal value of a∆ is three times greater than the average grain size and less than the damage zone.
The micro-grain size number of 16MnR steel is equal to 10 and the average diameter ( )d obtained by ASTM E112-96 is 11.2 µm.

The precipitates are known to be formed in specified orientations within each grain.
However, the effect of this directionality in macroscopic properties is negligible for polycrystalline alloys since the grains are randomly orientated.
Acknowledgments This work presented is supported by NSF through the grant ‘DMREF: Accelerating the Development of High Temperature Shape Memory Alloys’ under the Award Number: 1534534.

LianchengSun[9], according to the annular flume of fine sediment movement characteristic test results, put forward fine sediment starting, deposition velocity empirical formula suitable for sediment grain size in 0.0017 ~ 0.07 mm.
In order to make the annular flume experiments results closer to field conditions, including sand sample, water sample, Li Yu et al. [45]got an effective method from a large number of experiments.
Southard: Erosion of fine-grained marine sediment: Sea-floor and laboratory experiments.

Yan-hong Mu et al. studied the effects of hot stamping process parameters on the mechanical properties and microstructure of 30MnB5 and 22MnB5 after quenching [9], Chen et al. studied the effects of two key process parameters of holding pressure and holding time on B1500HS steel in hot stamping and quenching stage [10], Yu Wugang et al. used scanning electron microscopy and an attached EDS spectrometer to study the effects of different prealloying time on microstructure and composition distribution of hot-formed steel 22MnB5 zinc-based coatings [11], Zhu et al. developed a new model to predict grain growth during heating process and the flow stress of 22MnB5 with high hardenability through Gleeble simulation experiments [12].
Therefore, the removal of boron element is beneficial to avoid formation of boron carbide at the grain boundary and does not affect the hardenability of the required steel sheet, and the addition of niobium element is beneficial to the precipitation strengthening of the steel sheet, and is beneficial to the increase of the elongation of the steel sheet, thereby improving the processing performance of the hot formed steel for automobiles.
It can be seen from the figure that there is a certain amount of ferrite in the quenched structure in addition to a large number of martensite matrix.