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The results show that the technical indexes of cylinder pipe including chemical composition, nonmetallic inclusion grade, grain size, microstructure feature, surface quality, mechanical performance and bending test can meet the requirements with an international advanced level.
The technical difference of both is the number and shape of rolls.
Table 2 Nonmetallic inclusion grade Steel grade A(sulfides) B(oxides) C(silicates) D(globular oxides) thin coarse thin coarse thin coarse thin coarse requirements ≤2.5 ≤2.5 ≤2.5 ≤2.5 ≤2.5 ≤2.5 ≤2.5 ≤2.5 30CrMoTP 0 1.5 1.5 0 0 0 1.5 0 42CrMoTP 0 0 0.5 0 0 0 1 0 Grain size should be finer than level 8, the max. and the min. grain size from one sample piece should not bigger than level 3.
Table 3 Requirements and test results of grain size and microstructure Steel grade Grain size Rank difference Microstructure requirements ≥8 ≤3 Tempered sorbite 30CrMoTP 8.5 2 Tempered sorbite 42CrMoTP 8.5 2 Tempered sorbite Fig.5 Microstructure feature of 30CrMoTP and 42CrMoTP Mechanical performance tests were done as following: tensile test as per GB/T228, impact test as per GB/T229, and hardness HB test as per GB/T231.1.
Compared with technology of rolling or punching, it can fulfill multi-pass rolling to wall thickness while expanding. 2) The technical indexes of pipe including chemical composition, nonmetallic inclusion grade, grain size, microstructure feature, surface quality, mechanical performance and bending test can meet the requirements proposed according to relative cylinder standards.

The paper analyzes the influence of various geometric factors on the destruction possibility of aluminum alloys during pressing in an equal-channel step matrix, which allows to obtain an ultrafine-grained structure.
Therefore, recently, in the field of metal forming, there has been an increase in interest in the development of technologies that allow obtaining metals and alloys with a ultrafine-grained structure, which have an increased level of mechanical and operational properties, due to the implementation of severe plastic deformations in the volume of workpieces.
One of the promising methods for obtaining an ultrafine-grained structure in metals and alloys is equal-channel pressing in angular and step matrices of various designs [1-26], which makes it possible to implement significant severe plastic deformations without significant changes in the initial dimensions of the workpiece.
From previous studies [27-29], it is known that geometric factors, such as the angle of the junction of the matrix channels and the length of the matrix channels (to a greater extent, the length of the inclined channel), have a significant impact on the possibility of obtaining a ultrafine-grained structure when pressing metals in an equal-channel step matrix with a decrease in the required number of cycles due to the creation of a more favorable stress-strain state in the metal.
And only the choice of rational not only geometric parameters of deformation of workpieces in an equal-channel step matrix, but also technological ones, will make it possible to obtain a metal with a ultrafine-grained structure without its destruction and with minimal energy consumption.

The underlying surface layer model states that grains at the surface of a specimen are less constrained in their motion than grains in the interior part.
The grain structure of the bar material is shown in Figure 1.
Consequently, the grain size correlates with the size effects.
However, in order to be able to explain this decline by means of the grain size, further experiments must be carried out with another material and a comparable grain size.
For this purpose, a limit on the grain size should be defined.

The sub-boundary and the sub-grain appeared after aging 1000 h, 3000 h, respectively.
The W element exhibited seriously segregation on the grain boundaries, and the positions of the segregation were exactly consistent with the carbides on the grain boundaries.
The effect of pure matrix on of the T23 steel is related to many factors, such as dislocation density, sub-grain, grain size, bainite island microstructure.
No significant changes occurred in the grain size during the aging process.
However, the number and the size of dimples at the fracture of aging 3000 h apparently decreased compared with that of aging 500 h and 1000 h, exhibiting a slight decrease of the plasticity.

If a sufficient number of grains experiences a strain reversal and activates glide of ρB dislocations, then macroscopically plastic flow would begin at a lower stress than at the end of forward loading (BE).
If the dislocation density were to drop temporarily in a sufficient number of grains, then macroscopic hardening rate would experience a transient decrease.
Each grain is initially spherical.
The difference has to do with the number of extended barriers formed in pre-straining.
(iv) VPSC neglects elastic deformation and grain-grain interactions.

This aggregate is characterised by comparable grain strength to ceramic aggregates but, on the other hand, has a relatively high absorption rate of up to 30 %.
Currently, there are a number of suppliers on the market offering lightweight porous aggregates produced by different types of technologies.
These raw materials are transformed by the technological production process into a plastic dough, which has the ability to form a porous but, on the contrary, sintered structure of individual grains at high temperatures [1].
The individual grains of Liapor are fired in a rotary kiln at a temperature of 1200 °C, which guarantees optimal aggregate properties [5].
These aggregate grains are then fired by means of a so-called self-ignition process and sorted into the desired fractions. [5] Lightweight Concrete with Agglomerated Aggregate.

The growth pattern of Ca1–3xLn2xTiO3 grains was terracing growth.
When coordination number equal to 12, the effective ionic radius of Ca2+, La3+, Nd3+ and Sm3+ were 0.134 nm, 0.136 nm, 0.127 nm and 0.124 nm [9], respectively.
A large quantity of massive grains and a few granular grains, with intended and ladder-like microstructure even unambiguous interfacial angle are observed, indicating the terracing growth of grains.
However, when x=0.20 and Ln=Sm, granular grains increased obviously, probably corresponding to the secondary phase Sm2Ti2O7.
The growth pattern of Ca1–3xLn2xTiO3 grains was terracing growth.

They can be employed as micro-grinding tools because the convex parts of discharge craters formed on the tool surface can serve as cutting edges of abrasive grains in grinding wheels.
Although most small-diameter grinding wheels are fabricated by electroplating, it is difficult to electroplate a wheel shank with ultrafine grains, which are necessary for ultrasmall-diameter grinding wheels, with a constant pitch and protrusion height of the grains.
The grain size and hardness are 1 µm or larger and 5000 HK, respectively.
The maximum heights of these profiles are approximately 0.9 and 1.4 µm, respectively, which correspond to the protrusion height of the abrasive grains in grinding wheels.
A low crater density means a small number of convex parts of craters, implying that the grinding force per convex part is large enough to generate cracks and chippings.

Cu or V plates were used as the metallic electrodes with the equilibrium grain structure.
It is known that short-term heating over 490 K may anneal the grain-boundary dislocations without grains size change [9].
The grain-boundary dislocations are absent in these samples.
Therefore it is registered as a number of steps, each of which corresponds to a certain stage.
Unlike the nanostructured Cu and Ni the phase transition in the TiNi-based alloy is registered independently of the heating-cooling cycle number.

The structure is austenitic with polyhedral grains of varying size, grain boundaries are significant.
According to the number of rolls, there are two, three and multi-roll machines, according to the position of the rolls, they are divided into symmetrical and asymmetrical.
It is also possible to observe the plastic deformation in the grains of the material as deformation twins (Figure 4).
The curve is wider when the grain is finer (a larger number of small grains) and vice versa, the curve is narrower when the grain is coarser (larger quantity of large grains) (Figure 8).
Deformation twinning was well observed in the austenite grains.