Effect of rare earth on morphology and dispersion of TiB2 phase in Al-Ti-B alloy refiner

To investigate the effect of rare earth on size and distribution of TiB2 phase in aluminum alloy refiner,Al-5Ti-1B-RE master alloy was fabricated,and its microstructure and phase constitutions were investigated by the combination of first principles calculations and experimental investigation.The calculated results reveal that Ce has the most effective modification ability due to the most positive adsorption energy and the largest charge transfer value compared with other rare earth elements.Results of experimental investigation indicate that the addition of rare earth in the Al-5Ti-1B alloys can greatly refine the particle size of TiB2,improve the distribution of particles and lead to better refinement effect than that of the Al-5Ti-1B alloys without rare earth.Moreover,Ce has the best optimization effect,which agrees well with the calculated results.

Effect of compound treatment of rotating magnetic field and Al-5Ti-1B refiner on microstructure and properties of Al-5Cu alloy

The Al-5Cu alloys were prepared by different treatment methods,including adding a refiner Al-5Ti-1B,exerting a rotating magnetic field(RMF),and compound treatment of both refiner and RMF.The effects of treatment methods on the microstructure,properties,and solid solubility of the Al-5Cu alloy were investigated.The optimal magnetic field parameters and addition amount of refiner were confirmed by experiment.Results show that either RMF or adding refiner Al-5Ti-1B alone can refine the grain size,and the refining effect can be further improved by a compound refining treatment with optimized magnetic field parameters(120 A current and 8 Hz frequency) and 1.0wt.% Al-5Ti-1B refiner(RMF*+Al-5Ti-1B*).The average grain size is decreased to 68.1 μm,which is 60.8%,21.1%,and 83.5% lower than that of the alloy treated by the optimized rotating magnetic field,the Al-5Ti-1B refiner,and the alloy without any treatment,respectively.The tensile strength and elongation of the alloy reach 232.5 MPa and 18.6%,respectively,which are obviously higher than those of the alloys treated by rotating magnetic field,Al-5Ti-1B refiner,and the alloy without any treatment,respectively.Additionally,the solid solubility of the alloy is also obviously improved compared to the alloys treated by other methods.

Effect of Refiner Plate Bar Angle and Pulp Properties on the Low Consistency Refining Efficiency in Terms of Power Consumption

Power consumption is the energy source of the impact on fibers or pulp during low-consistency(LC)pulp refining,and the strength of refining affects refining quality and efficiency.The pulp properties,operating parameters,and bar parameters of the refiner plates are important parameters affecting refining efficiency,which can be defined as the ratio of net to total refining power.In this study,LC refining trials for pulps with different consistencies and fiber lengths were conducted using five isometric straightbar plates with different bar angles to explore the influences of the plate bar angle and pulp properties on the no-load power,impact capacity on fibers and refining efficiency.It was found that the no-load power of the LC refining process decreased with an increase in the plate bar angle while increased when pulp with higher consistency was refined under the same refining conditions.However,the effect of pulp consistency on the no-load power can be neglected when refining is conducted using plates with larger bar angles.Meanwhile,a critical bar angle for straight-bar plates in LC refining may exist,which has the strongest impact on the pulp and highest refining efficiency under the same refining conditions.In addition,the impact capacity of the plate on the pulp and refining efficiency in LC refining can be enhanced by appropriately increasing the pulp consistency and average fiber length when the bar angle of the refiner plate with a sector angle of 40°is less than 30°.Therefore,the efficiency and power consumption of the LC refining process can be adjusted by optimizing the pulp consistency and bar parameters of the refining plates.

Effects of Al-Ti-B-RE grain refiner on microstructure and mechanical properties of Al-7.0Si-0.55Mg alloy

To investigate the effects of Al-Ti-B-RE grain refiner on microstructure and mechanical properties of Al-7.0Si-0.55Mg （A357） alloy, some novel Al-7.0Si-0.55Mg alloys added with different amount of Al-STi-1B-RE grain refiner with different RE composition were prepared by vacuum-melting. The microstructure and fracture behavior of the AI-7.0Si-0.55Mg alloys with the grain refiners were observed by X-ray diffraction （XRD）, optical microscopy （OM）, scanning electron microscopy （SEM）, and the mechanical properties of the alloys were tested in mechanical testing machine at room temperature. The observation of AI-Ti-B-RE morphology and internal structure of the particles reveals that it exhibits a TiAl3/Ti2Al20RE core-shell structure via heterogeneous TiB2 nuclei. The tensile strength of Al-7.0Si-0.55Mg alloys with Al-5Ti-1B-3.0RE grain refiner reaches the peak value at the same addition （0.2%） of grain refiner.

Effect of nano TiN/Ti refiner on as-cast and hot-working microstructure of commercial purity aluminum

A novel type nano TiN/Ti composite grain refiner （TiN/Ti refiner） was prepared by high energy ball milling, and its effect on as-cast and hot-working microstructure of commercial purity aluminum （pure Al） was investigated. The results show that TiN/Ti refiner exhibits excellent grain refining performances on pure Al. With an addition of 0.2% TiN/Ti refiner, the average grain size of pure Al decreases to 82 μm, which is smaller than that of pure Ti and Al 5Ti 1B master alloy as refiners. The microstructure of weld joint of pure Al with 0.1% TiN/Ti refiner is fine equiaxed grains and the hardness of weld joint is higher than that of the base metal. For pure Al with 40% cold deformation and recrystallization at 250 °C for 1.0 h, the grains of the sample added 0.1% Ti powder have an obvious grain growth behavior. In contrast, oriented grains caused by deformation have been eliminated, and there is no obvious grain growth in pure Al refined with 0.1% TiN/Ti refiner, indicating that nano TiN in the refiner inhibits the growth of grain during recrystallization.

Study on the new materials for fiberboard refiner plate of defibrator

Defibrator is a very important machine in the wood industry for producing fiberboard. The refiner plates are the key parts of defibrator that directly act with the wood, and broken easily. The working life of the refiner plates is of significance to the wood industry. It may affect refining quality, production efficiency, and power consumption. In this paper, the abrasion resistance of the refiner plate made of different materials, the stainless steels and high chromium cast irons, were tested and compared. The results showed that abrasion resistance of refiner plate made of high chromium cast irons was better than that of the stainless steel materials. Although the two kinds of materials have the same compositions, their abrasion resistances have ap-parent difference. The main reason is that the material microstructures have very important effects on their performance. The refiner plates made of developed high chromium cast irons don抰 demand the complex heat treatment. This can simplify the producing process, save the cost of production, decrease labor strength, and increase the production efficiency.

Effect of La on Microstructure and Grain-Refining Performance of Al-Ti-C Grain Refiner

Al-Ti-C grain refiner was prepared by SHS （self-propagating high-temperature synthesis ）-melting technique. The effect of La on the microstructures of grain refiner was studied by OM, TEM, SEM, XRD, and EDS. The experimental results indicate that La can improve the wettability between liquid aluminum and graphite ; the addition of La results in dispersive distribution of TiAl3 and TiC particles in the matrix. An excellent grain refining performance of Al-Ti-C grain refiner on commercially pure Al was obtained.

Microstructure and phase forming process of Al-3Ti-0.2C-1RE grain refiner

An Al-3Ti-0.2C-1RE grain refiner was prepared by in-situ reaction method.The microstructure was investigated by optical microscopy(OM),scanning electron microscopy(SEM) equipped with energy-dispersive spectrometry(EDS) and X-ray diffraction(XRD).The results show that the Al-3Ti-0.2C-1RE grain refiner is composed of α-Al,TiAl3,TiC and Ti2 Al20 Ce phases.Compared with Al-3Ti-0.2C refiner,the morphology of TiAl3 phase is changed and Ti2 Al20 Ce phases form with the addition of RE.Accordingly,the refining performance is improved.The phase forming process of the refiner is as follows: Blocky Ti2 Al20 Ce and fine blocky TiAl3 form in the melt at the initial stage of reaction,then the fine blocky TiAl3 gradually disappears,and the blocky Ti2 Al20 Ce grows bigger with the increase of holding time.The predominant mechanism to synthesize TiC particles is the reaction between high concentration of solute Ti atoms and graphite particles.

ARTIFICIAL NEURAL NETWORK MODELLING OF A WOOD CHIP REFINER

1 INTRODUCTIONWood chip refining is the most critical step in mechanical pulping.Commercical experi-ences have been gained for years.Modelling and control of chip refiners,however,pose a challenge mainly because of the stochastic nature of the process.Some attemptshave been made to employ factor analysis technique[1]in the modelling andsimulating of refiner operation[2,3].Strand[2]used common factors as links betweenintrinsic fibre properties and pulp quality.He believed that a qualitative concept onthe physical nature of these common factors could be arrived at,and thus would helpto understand what refining variables need to be controlled or adjusted in order to im-prove pulp quality.However,the linear model used in factor analysis is based on theassumption that the interactions among the system variables are linear,which,ofcourse,is not true in practice.

A new fabricating technique of refiner plate

It was discussed how refiner plate is produced by a new process, such as three dimension making die with computer technology, shell molding, optimizing the alloy and controlling shakeout time with computer. Results confirmed that lead-time was decreased and product customization was improved in making die by using computer technology. At the same time, precision molding can decrease the reject ratio of refiner plates, and optimizing the alloy and shakeout time can eliminate the need for heat treatment. The new fabricating process showed several advantages over the traditional process in increasing toughness, better casting precision, elimination of the annealing treatment stage and raising production efficiency.

Simulation of the Flow Conditions in Different Types of Bar Structures of Disc Refiner

Disc refiner is a critical equipment in the pulping and papermaking industry, pulp is refined in the refining zone, and different bar structures of refining disc constitute the different refining zones. With the use of the 3D modeling software SOLIDWORKS, five different refining discs that are commonly used in low consistency pulping, were built. The five refining discs were simulated and analyzed using the Computational Fluid Dynamics(CFD)software. The distribution of pulp velocity and surface shear stress, which is displayed between the bar and groove structures, can indirectly show the stress conditions on the refining discs. This paper provides a theoretical basis for research on the bar and groove failure of the refining discs.

Design Method of Curved-bar Refining Plates for Disc Refiner

Straight-and curved-bar refining plates are two important types of plates commonly used in disc refiners in the papermaking industry.Theoretically,the curved-bar refining plate has a relatively uniform bar interaction angle,which indicates uniform refining effects.The bar angle of the curved bar was proposed and two typical curved-bar plates,the three-stage radial curved-bar plate and isometric curved-bar plate,were designed in this paper.The arc equations of the curved-bar center line and curved-bar edges were established and finally,the specific edge load(SEL)of the curved-bar plate was derived.The determination of bar parameters was discussed,which provides a theoretical basis for the design of curved-bar plates.

Al-Ti-C Grain Refiner Made by Ultrasonic Levitation

An electrostrictive uniaxial ultrasonic levitation reaction system was designed to perform TiC synthesis reaction by suspending graphite powder in Al-3Ti melt and an Al-3Ti-0.15C grain refiner alloy was obtained. The results show that sound pressure node in which graphite suspends is formed in the melt between radiation block and reflecting board by ultrasonic and TiAl3 particles congregate around C powder. Meanwhile, due to ultrasonic cavitation, dissolved TiAl3 provides better surface condition for the synthesis reaction of TiC. The reaction route is that C and dissolved Ti react to form TiC. Ultrasonic cavitation has a thermal activation effect on TiC particles and Al-3Ti-0.15C refiner has excellent microstructural refining effect on α-Al.

RIPP Works on Crude Formulation Technique to Grapple with Refiners' Tough Problems

Currently ＂The Crude Formulation Technique＂ developed by the SINOPEC Research Institute of Petroleum Processing（RIPP） has passed the technical review sponsored by the Sinopec Corp.This technique by means of adopting the advanced algorithm on the basis of the crude assay data bank and the large crude spectroscopic database can intelligently blend together different kinds of crude oils to obtain multiple crude formulations, the quality of which is quite close to the target crude in a bid to provide technical support to the refining enterprises in the area of crude procurement and sustained property stabilization of crude oils pro-cessed thereby.

Refiners' alliance eases competition

Analysts say an independent oil refiners’alliance in Shandong will help the teapot refiners enhance bargaining power and reduce vicious competition amidan excess capacity in the sector.Several teapots in Shandong have set up a refining conglomerate recently with a planned registered capital reaching 90 billion yuan($13.67 billion).This will combine the country’s largest independent oil refineries,known as teapots。

Comparison of Potential Environmental Impacts on the Production of Gasoline and Kerosene, Al-Daura Refinery, Baghdad, Iraq

Oil represents the main energy sources used by mankind. In addition, petroleum products serve as feedstock for several consumer goods, thus playing an important growing role in people’s lives. For this reason there are various software applications designed to do the environmental assessment to see their impact on the environment. Among these is SimaPro software package designed to make a valuable contribution. It is a powerful tool for analyzing the environmental impact of products during their whole life cycle. In this study, it was applied to analyze and evaluate the impacts for Al-Daura refinery for the gasoline and kerosene fuel production. This refinery located in Baghdad, Iraq was analyzed. The results of the life cycle assessment (LCA) show that gasoline has a (single score) of the order of 11.1 point for each 1 cubic meter produce from gasoline fuel compared with 4.83 point for each 1 cubic meter produce from kerosene. Global warming, respiratory inorganics and non-renewable energy were the most effective environmental impacts.

Microstructural evolution and intermetallic formation in Al-8wt% Si-0.8wt% Fe alloy due to grain refiner and modifier additions

An alloy of A1-8wt% Si-0.8wt% Fe was cast in a metallic die, and its microstrucmral changes due to Ti-B refiner and Sr modifier additions were studied. Apart from usual refinement and modification of the microstructure, some mutual influences of the additives took place, and no mutual poisoning effects by these additives, in combined form, were observed. It was noticed that the dimensions of the iron-rich intermetallics were influenced by the additives causing them to become larger. The needle-shaped intermetallics that were obtained from refiner addition became thicker and longer when adding the modifier. It was also found that a-Al and eutectic silicon phases preferentially nucleate on different types of intermetallic compounds. The more iron content of the intermetallic compounds and the more changes in their dimensions occurred. Formation of the shrinkage porosities was also observed.

Crystallographic study of Al_3Zr and Al_3Nb as grain refiners for Al alloys

The potency of Al3Zr and Al3Nb as grain refiners for Al alloys was investigated from a crystallographic point of view using the edge-to-edge matching （E2EM） model. The results show that both Al3Zr and Al3Nb have small values of interatomic spacing misfit and interplanar spacing mismatch with respect to Al. Furthermore, energetically favourable orientation relationships predicted by the model exist between Al and each of these two intermetallic phases. In the light of the edge-to-edge matching model predictions, it is suggested that both Al3Zr and Al3Nb are potent heterogeneous nucleation refiners for Al grains from the crystallographic point of view. The present crystallographic analysis provides a more reasonable explanation for the significant grain refinement obtained in the peritectic Al-Zr and Al-Nb alloys and also provides fresh insight into the understanding of the grain refinement mechanism of Al alloys.

Energy Consumption and Analysis on Energy Saving Measures at SINOPEC's Large Refineries

This article sums up the energy consumption of process units and the overall energy consumption of 10 Mt/a class refineries constructed or revamped in recent years. The energy saving measures adopted in design of these refineries are analyzed and discussed. Finally, this article also makes comments and puts forward recommendations on the objectives for energy conservation at refineries in the future.

Effect of Si-addition as a grain refiner on microstructure and properties of Ti-6Al-4V Alloy

Two different Ti alloys were cast in a graphite mould using vacuum induction skull melting furnace. The first alloy was Ti-6Al-4V and the second was Ti-6Al-4V 0.5Si. Silicon as a grain refiner was added into Ti-6Al-4V alloy, and the effects of Si-addition on the microstructure and properties of the as-cast and swaged alloys were investigated. Hot swaging at 900 °C was performed on the cast samples and then two different thermal treatments were applied. The first treatment was done by heating the swaged samples at 1050 °C to produce fine lamella structure, while the second treatment was carried out at 1050 °C and then decreased the temperature to 800 °C for getting coarse lamella structure. An addition of 0.5% Si to Ti-6Al-4V alloy decreased the grain size of the as-cast sample from 627 to 337 μm. There was an increase in ultimate tensile strength of about 25 MPa for the as-cast Ti-6Al-4V 0.5Si alloy compared to Ti-6Al-4V due to the refinement effect caused by Si addition. A maximum ultimate tensile strength of 1380 MPa and a minimum corrosion rate （1.35×10 6 mm/a in Hank’s solution and 5.78×10 4 mm/a in NaCl solution） were reported for the heat treated fine lamella structure of Ti-6Al-4V 0.5Si alloy. The wear rate was decreased to about 50% by adding 0.5% Si at low sliding speeds and to about 73% at high sliding speeds.