Grain evolution during hot ring rolling of as-cast 42CrMo ring billets

2021 ◽  
Vol 63 (7) ◽  
pp. 606-611
Author(s):  
Jiachen Liu ◽  
Jinliang Wang ◽  
Huiping Qi ◽  
Huiqin Chen
Keyword(s):  
Grain Size ◽  
Grain Refinement ◽  
Effective Strain ◽  
Fem Simulation ◽  
Ring Rolling ◽  
Air Cooling ◽  
Zonal Distribution ◽  
Average Grain Size ◽  
Refinement Mechanism ◽  
Hot Rolled

Abstract During hot ring rolling and subsequent air-cooling processes, the as-cast metal alloy undergoes a complicated microstructural evolution. In this paper, the grain refinement of as-cast 42CrMo ring billet during hot ring rolling and air-cooling was conducted by FEM simulation and tests. Moreover, the grain refinement mechanism of as-cast 42CrMo was also studied by comparison of single-pass deformation and multi-pass deformation with short pass interval time, with the purpose of studying the influence of the deformation process on grain refinement supported by the results of FEM simulation. As a result, effective strain and average grain size of the ring show zonal distribution characteristics The effective strain on the inner and outer layers of the ring is large, contributing to fine and homogeneous grains. In contrast, the cumulated effective strain on the interlayer of the ring is small, resulting in inhomogeneous and mixed grains and large average grain size. Grain growth occurs during subsequent air-cooling. The microstructural distribution of the hot rolled ring was confirmed by a hot ring rolling test.

Modeling and Numerical Simulation Research on Hollow Steel Ingot Forging Process of Heavy Cylinder Forging

2013 ◽  
Vol 712-715 ◽  
pp. 627-632
Author(s):  
Min Liu ◽  
Qing Xian Ma
Keyword(s):  
Numerical Simulation ◽  
Grain Size ◽  
Shear Zone ◽  
Grain Refinement ◽  
Steel Ingot ◽  
Effective Strain ◽  
Meridian Plane ◽  
Forging Process ◽  
Forming Load ◽  
Average Grain Size

Aiming at the disadvantages of low utilization ratio of steel ingot, uneven microstructure properties and long production period in the solid steel ingot forging process of heavy cylinder forgings such as reactor pressure vessel, a new shortened process using hollow steel ingot was proposed. By means of modeling of lead sample and DEFORM-3D numerical simulation, the deformation law and grain refinement behavior for 162 ton hollow steel ingot upsetting at different reduction ratios, pressing speeds and friction factors were investigated, and the formation rule of inner-wall defects in upsetting of hollow steel ingots with different shape factors was further analyzed. Simulation results show that the severest deformation occurs in the shear zone of meridian plane in the upsetting process of hollow steel ingot, and the average grain size in the shear zone is the smallest. As pressing speed increases, the forming load gradually increases and the deformation uniformity gets worse, while the average grain size decreases. An increase in friction factor can increase the peak value of effective strain, but it significantly reduces the deformation uniformity, increases the forming load and goes against grain refinement. Moreover, the four kinds of defects on the inner wall of steel ingot can be eliminated effectively by referring to the plotted defect control curve for hollow steel ingot during high temperature upsetting.

Enhancement of Grain Refinement and Formability of Cross Roll Rolled Ni-10Cr Alloy

2013 ◽  
Vol 761 ◽  
pp. 95-99
Author(s):  
Kuk Hyun Song ◽  
Han Sol Kim ◽  
Won Yong Kim
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Grain Refinement ◽  
Transverse Direction ◽  
Effective Strain ◽  
Initial Material ◽  
Rolled Material ◽  
Roll Mill ◽  
Average Grain Size ◽  
Conventional Rolling

This study evaluated the microstructure and mechanical properties enhancement of cross roll rolled Ni-10Cr alloy, comparing with conventional rolled material. Cold rolling was carried out to 90% thickness reduction and subsequently annealed at 700 °C for 30 min to obtain the fully recrystallized microstructure. Particularly, cross roll rolling was carried out at a tilted roll mill condition of 5º from the transverse direction in RD – TD plane. Application of cross roll rolling on Ni-10Cr alloy contributed to the notable grain refinement due to higher effective strain than that of conventional rolling, consequently, average grain size was refined from 135 µm in initial material to 4.2 µm in cross roll rolled material. Furthermore, //ND texture in CRR material was well developed than that of CR material, which contributed to the mechanical properties and formability enhancement.

Study on Refinement Mechanism of Sc and Zr as-Cast Al-7.2Zn-2.2Mg-1.8Cu Alloys

2013 ◽  
Vol 372 ◽  
pp. 66-69
Author(s):  
Zhi Gang Wang ◽  
Jun Xu ◽  
Bao Li ◽  
Zhi Feng Zhang
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Grain Size ◽  
Grain Refinement ◽  
Heterogeneous Nucleation ◽  
Composite Particles ◽  
Cast Ingot ◽  
Average Grain Size ◽  
Refinement Mechanism ◽  
Scanning Electron

The effect of trace Sc and Zr on grain refinement of Al-7.2Zn-2.2Mg-1.8Cu as-cast ingot was studied by using optical microscopy and scanning electron microscopy with EDS. The results show that addition of only 0.20% Zr or 0. 20% Sc to Al-7.2Zn-2.2Mg-1.8Cu alloy can refine grains to a certain degree, and the addition of 0.10% Sc+0.20%Zr leads to stronger grain refinement, the average grain size is only 10-15μm. Al3Sc/Al3Zr composite particles in the melt work as the nucleation of heterogeneous nucleation during solidification.

scholarly journals Effect of Vanadium Reinforcement on the Microstructure and Mechanical Properties of Magnesium Matrix Composites

Crystals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 806
Author(s):  
Liqing Sun ◽  
Shuai Sun ◽  
Haiping Zhou ◽  
Hongbin Zhang ◽  
Gang Wang ◽  
...  
Keyword(s):  
Grain Size ◽  
Grain Refinement ◽  
Milling Process ◽  
Mg Alloy ◽  
Matrix Composites ◽  
Magnesium Matrix Composites ◽  
Pinning Effect ◽  
Average Grain Size ◽  
The Matrix ◽  
Hot Press Sintering

In this work, vanadium particles (VP) were utilized as a novel reinforcement of AZ31 magnesium (Mg) alloy. The nanocrystalline (NC) AZ31–VP composites were prepared via mechanical milling (MM) and vacuum hot-press sintering. During the milling process, the presence of VP contributed to the cold welding and fracture mechanism, resulting in the acceleration of the milling process. Additionally, increasing the VP content accelerated the grain refinement of the matrix during the milling process. After milling for 90 h, the average grain size of AZ31-X wt % Vp (X = 5, 7.5, 10) was refined to only about 23 nm, 19 nm and 16 nm, respectively. In the meantime, VP was refined to sub-micron scale and distributed uniformly in the matrix, exhibiting excellent interfacial bonding with the matrix. After the sintering process, the average grain size of AZ31-X wt % VP (X = 5, 7.5, 10) composites still remained at the NC scale, which was mainly caused by the pinning effect of VP. Besides that, the porosity of the sintered composites was no more than 7.8%, indicating a good densification effect. As a result, there was little difference between the theoretical and real density. Compared to as-cast AZ31 Mg alloy, the microhardness of sintered AZ31-X wt % VP (X = 5, 7.5, 10) composites increased by 65%, 87% and 96%, respectively, owing to the strengthening mechanisms of grain refinement strengthening, Orowan strengthening and load-bearing effects.

scholarly journals Grain Refinement of a Powder Nickel-Base Superalloy Using Hot Deformation and Slow-Cooling

Materials ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 1978 ◽  
Author(s):  
Xianqiang Fan ◽  
Zhipeng Guo ◽  
Xiaofeng Wang ◽  
Jie Yang ◽  
Jinwen Zou
Keyword(s):  
Grain Size ◽  
Grain Refinement ◽  
Hot Deformation ◽  
Nickel Base Superalloy ◽  
Polycrystalline Nickel ◽  
Slow Cooling ◽  
Homogeneous Microstructure ◽  
Average Grain Size ◽  
Nickel Base ◽  
Base Superalloy

A pre-hot-deformation process was applied for a polycrystalline nickel-base superalloy to active deformation twins and dislocations, and subsequent slow cooling treatment was used to achieve grain refinement and microstructure homogenization. The microstructural evolution of the alloy was investigated, and the corresponding underlying mechanism was discussed. It was found that twinning mainly occurred in large grains during pre-hot-deformation owing to the stress concentration surrounding the large grains. High density dislocations were found in large grains, and the dislocation density increased approaching the grain boundary. The average grain size was refined from 30 μm to 13 μm after slow cooling with a standard deviation of grain size decreasing from 10.8 to 2.8, indicating a homogeneous microstructure. The grain refinement and microstructure homogenization during cooling process could be achieved via (i) static recrystallization (SRX), (ii) interaction of twin tips and γ’ precipitates, and (iii) grain coarsening hindered by γ’ precipitates in grain boundaries.

scholarly journals Crystallography of grain refinement in cast zinc–copper alloys

2015 ◽  
Vol 48 (3) ◽  
pp. 890-900 ◽  
Author(s):  
Zhilin Liu ◽  
Dong Qiu ◽  
Feng Wang ◽  
John A. Taylor ◽  
Mingxing Zhang
Keyword(s):  
Grain Size ◽  
Grain Refinement ◽  
Copper Alloys ◽  
Diffraction Method ◽  
Electron Backscattered Diffraction ◽  
Grain Coarsening ◽  
Cu Content ◽  
Edge Matching ◽  
Average Grain Size ◽  
Cast Alloys

Adding the peritectic forming element Cu effectively reduced the average grain size of cast Zn by over 85%. At a specified cast condition, the smallest grain size was obtained at 2 wt% Cu addition. A further increase in Cu content led to grain coarsening in the cast Zn–Cu alloys. Although the solute effect of Cu was predominately responsible for the grain refinement through restriction of the grain growth, it was found that the variation of grain size is also closely related to the formation of the pro-peritectic phase, ∊-CuZn4. Crystallographic calculations using the edge-to-edge matching model showed low interatomic misfit and interplanar mismatch between Zn and the ∊-CuZn4phase. In addition, a reproducible h.c.p.–h.c.p. (h.c.p. denotes hexagonal close-packed) orientation relationship between Zn and the ∊-CuZn4particles (located within the Zn grain centres) was also experimentally determined using the electron backscattered diffraction method. This indicated the high potency of the pro-peritectic ∊-CuZn4particles as effective heterogeneous nucleation sites for η-Zn, which further refined the Zn grains. However, when the Cu content was over 2.0 wt%, formation of large ∊-CuZn4particles resulted in grain coarsening of the cast alloys.

The Effect of Rolling Temperature on Grain Size and Toughness in Hot Rolled Q345E H-Beam Steel

2018 ◽  
Vol 279 ◽  
pp. 26-29
Author(s):  
Li Ping Sun ◽  
Guo Hui Zhu ◽  
Jun Xing ◽  
Qi Wei Chen
Keyword(s):  
Grain Size ◽  
Rolling Temperature ◽  
Experimental Results ◽  
Average Grain Size ◽  
H Beam ◽  
Rolling Temperatures ◽  
Hot Rolled

The effect of enter rolling temperatures on the grain size and toughness was investigated in Q345E H-beam steels. The experimental results shown that the grain size exhibited a complicated phenomenon with rolling temperature instead of refining as the temperature decreased as expected. It would be interpreted by the behaviors of deformation and recrystallization in austenite during rolling. The toughness is not only depended on the average grain size but also on the distribution of grain size as well as morphology of pearlite. The toughness would be decreased by the mixed grain size.

scholarly journals Quantitative approach to realization of ultrasonic grain refinement of Al-7Si-2Cu-1Mg alloy

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Soo-Bae Kim ◽  
Young-Hee Cho ◽  
Min-Su Jo ◽  
Jae-Gil Jung ◽  
Young-Kook Lee ◽  
...  
Keyword(s):  
Particle Size ◽  
Grain Size ◽  
Grain Refinement ◽  
Particle Diameter ◽  
Nucleation Site ◽  
Melt Temperature ◽  
Transmission Electron ◽  
Refinement Mechanism ◽  
Ultrasonic Melt Treatment ◽  
The Relationship

AbstractUltrasonic melt treatment (UST) was applied to Al-7Si-2Cu-1Mg melt at various temperatures of 620, 650, 700 and 785 °C. MgAl2O4 particles which were often found to be densely populated along oxide films, became effectively dispersed and well-wetted by UST. Transmission electron microscopy work combined with crystallography analysis clearly indicates that MgAl2O4 particles can act as α-Al nucleation site with the aid of UST. However, with UST, grain refinement occurred only at temperature of 620 °C and the grain size increased from 97 to 351 μm with increase of melt temperature to 785 °C for UST. In quantitative analysis of grain size and MgAl2O4 particle diameter, it was found that ultrasonic de-agglomeration decreased mean particle size of the MgAl2O4 particles, significantly reducing size from 1.2 to 0.4 μm when temperature increased from 620 to 785 °C. Such a size reduction with increased number of MgAl2O4 particles does not always guarantee grain refinement. Thus, in this work, detailed condition for achieving grain refinement by UST is discussed based on quantitative measurement. Furthermore, we tried to suggest the most valid grain refinement mechanism among the known mechanisms by investigation of the relationship between grain size and particle size with variation of melt temperature.

Influence of Stacking Fault Energy on the Microstructures and Grain Refinement in the Cu-Al Alloys during Equal-Channel Angular Pressing

2010 ◽  
Vol 667-669 ◽  
pp. 379-384 ◽  
Author(s):  
X.H. An ◽  
Shi Ding Wu ◽  
Z.F. Zhang
Keyword(s):  
Grain Size ◽  
Grain Refinement ◽  
Equal Channel Angular Pressing ◽  
Al Alloys ◽  
Stacking Fault ◽  
High Recovery ◽  
Angular Pressing ◽  
High Recovery Rate ◽  
Refinement Mechanism ◽  
Stacking Fault Energies

The microstructural evolution and grain refinement of Cu-Al alloys with different stacking fault energies (SFEs) processed by equal-channel angular pressing (ECAP) were investigated. The grain refinement mechanism was gradually transformed from dislocation subdivision to twin fragmentation with tailoring the SFE of Cu-Al alloys. Concurrent with the transition of grain refinement mechanism, the grain size can be refined into from ultrafine region (1 m~100 nm) to the nanoscale (<100 nm) and then it is found that the minimum equilibrium grain size decreases in a roughly linear way with lowering the SFE. Moreover, in combination with the previous results, it is proposed that the formation of a uniform ultrafine microstructure can be formed more readily in the materials with high SFE due to their high recovery rate of dislocations and in the materials with low SFE due to the easy formation of a homogeneously-twinned microstructure.

Effect of Mo doping on the microstructure and properties of an Fe36Ni Invar alloy

2020 ◽  
Vol 34 (31) ◽  
pp. 2050297
Author(s):  
Liming Dong ◽  
Zhaopeng Yu ◽  
Xianjun Hu ◽  
Fang Feng
Keyword(s):  
Grain Size ◽  
Thermal Expansion ◽  
Grain Boundaries ◽  
Coefficient Of Thermal Expansion ◽  
Solution Temperature ◽  
Microstructure And Properties ◽  
Invar Alloys ◽  
Average Grain Size ◽  
Mo Content ◽  
Hot Rolled

The effects of doping with different Mo contents on the microstructure and properties of Fe36Ni Invar alloys were investigated. The results show that when 0.9 wt.% Mo and 1.8 wt.% Mo were added to Fe36Ni, the tensile strengths of the hot rolled alloys were 46 and 61 MPa higher than that of the 0 wt.% Mo sample, respectively. With an increase in Mo content from 0.9 to 1.8 wt.%, the solution temperature of the highest hardness after heat treatment increased from 800[Formula: see text]C to 850[Formula: see text]C, respectively. The addition of 0.9 wt.% Mo refined the average grain size from 37 to 15 [Formula: see text]m, and an excessive amount of Mo (1.8 wt.%) did not refine the grains further. After Mo was added, the precipitates on the original grain boundaries changed into nanoprecipitates dispersed in the grain boundaries and inside the grains. Mo was present in the alloy in the form of a carbide and in solid solution, which affected the magnetic lattice effect and increased the thermal expansion coefficient of the alloy. However, upon comparing the samples doped with 0 wt.% Mo, 0.9 wt.% Mo and 1.8 wt.% Mo, it was found that the addition of 0.9 wt.% Mo not only refined the grain size and improved the mechanical properties of the alloy but also led to a low coefficient of thermal expansion (CTE) over the range from 20[Formula: see text]C to 300[Formula: see text]C.

Sign in / Sign up

Export Citation Format

Share Document