节能型硫酸锰连续加热结晶工艺试验研究

针对传统硫酸锰高温蒸发浓缩结晶工艺存在结垢严重、耗能大等问题,提出一种节能型硫酸锰连续加热结晶工艺,并对该工艺进行试验研究。结果表明,当管内平均流速为0.8 m/s,近壁面溶液的名义过饱和度Δcsur<3.09%,试验运行140 min时,空管传热系数下降45%,而插入振动螺旋的换热管传热系数基本稳定不变。当Δcsur<3.09%时,管内固体粒子体积分数对振动螺旋的传热、防垢性能有显著影响。粒子体积分数为1.0%的传热系数比仅加入振动螺旋时高15%。从可行的绝对过饱和度角度,对新型硫酸锰连续加热结晶工艺与传统的蒸发浓缩工艺进行了能耗对比分析,新工艺节能约53%。

提高复合钻井条件下文留构造岩屑录井质量

由于复合钻井技术的推广,特别是PDC钻头的应用,给现场地质录井带来了技术挑战。该文针对东濮凹陷油气藏的重要标志层—盐膏岩,在PDC钻头条件下与粉砂岩岩屑不易识别的问题,从PDC钻头的破岩机理、盐膏岩的地质录井特征,以及盐膏岩与粉砂岩的组成成分和物理化学性质入手,总结出稀盐酸、氢氟酸滴试、微观对比和岩屑加热结晶四种不同的粉砂岩与岩屑岩鉴别方法,拓展现场录井岩性识别方法,为录井人员准确卡准层位增加了判别依据,提高了工程异常预报准确性,为安全钻井提供技术支持。

Effect of calcium addition on microstructure and texture modification of Mg rolled sheets

The mechanical properties and texture of AM60（Mg-6.0Al-0.3Mn,mass fraction %） and ZXM200（Mg-1.6Zn-0.5Ca-0.2Mn） Mg alloys subjected to multi-pass hot rolling were investigated.The finer recrystallized grains usually exhibit particular preferred orientations and then alter the total texture feature of rolled sheets.Ca solid solution into Mg matrix serves to the formation of texture component with c-axis rotated away from normal direction towards transverse direction and then weakens the overall texture intensity,resulting in a similar anisotropic characteristic to RE-containing Mg alloys.

Hot deformation behavior and processing map of Cu-Ni-Si-P alloy

The high-temperature deformation behavior of Cu-Ni-Si-P alloy was investigated by using the hot compression test in the temperature range of 600-800 ℃ and strain rate of 0.01-5 s-1. The hot deformation activation energy, Q, was calculated and the hot compression constitutive equation was established. The processing maps of the alloy were constructed based on the experiment data and the forging process parameters were then optimized based on the generated maps for forging process determination. The flow behavior and the microstructural mechanism of the alloy were studied. The flow stress of the Cu-Ni-Si-P alloy increases with increasing strain rate and decreasing deformation temperature, and the dynamic recrystallization temperature of alloy is around 700 ℃. The hot deformation activation energy for dynamic recrystallization is determined as 485.6 kJ/mol. The processing maps for the alloy obtained at strains of 0.3 and 0.5 were used to predict the instability regimes occurring at the strain rate more than 1 s-1 and low temperature （〈650 ℃）. The optimum range for the alloy hot deformation processing in the safe domain obtained from the processing map is 750-800 ℃ at the strain rate of 0.01-0.1 s i The characteristic microstructures predicted from the processing map agree well with the results of microstructural observations.

Hot deformation behavior of Al-9.0Mg-0.5Mn-0.1Ti alloy based on processing maps

Hot deformation behavior of extrusion preform of the spray-formed Al-9.0Mg-0.5Mn-0.1Ti alloy was studied using hot compression tests over deformation temperature range of 300-450 ℃ and strain rate range of 0.01-10 s-1. On the basis of experiments and dynamic material model, 2D processing maps and 3D power dissipation maps were developed for identification of exact instability regions and optimization of hot processing parameters. The experimental results indicated that the efficiency factor of energy dissipate （η） lowered to the minimum value when the deformation conditions located at the strain of 0.4, temperature of 300 ° C and strain rate of 1 s-1. The softening mechanism was dynamic recovery, the grain shape was mainly flat, and the portion of high angle grain boundary （〉15°） was 34%. While increasing the deformation temperature to 400 ° C and decreasing the strain rate to 0.1 s-1, a maximum value of η was obtained. It can be found that the main softening mechanism was dynamic recrystallization, the structures were completely recrystallized, and the portion of high angle grain boundary accounted for 86.5%. According to 2D processing maps and 3D power dissipation maps, the optimum processing conditions for the extrusion preform of the spray-formed Al？9.0Mg？0.5Mn？0.1Ti alloy were in the deformation temperature range of 340-450 ° C and the strain rate range of 0.01-0.1 s-1 with the power dissipation efficiency range of 38%？43%.

Hot deformation behavior and processing maps of as-cast Mg-8Zn-1Al-0.5Cu-0.5Mn alloy

The hot deformation behavior of as-cast Mg-8Zn-1Al-0.5Cu-0.5Mn alloy was studied by hot compression tests at temperatures of 200-350 °C and strain rates of 0.001-1 s-1.The results show that the flow stress increases significantly with increasing strain rate,and decreases as the temperature increases.The flow stress model based on the regression analysis was developed to predict the flow behavior of Mg-8Zn-1Al-0.5Cu-0.5Mn alloy during the hot compression,and the model shows a good agreement with experimental results.Meanwhile,the processing maps were established according to the dynamic materials model.The processing maps show that the increase of strain enlarges the instability domains,and the alloy shows good hot workability at high temperatures and low strain rates.

不同脱盐方式对酱油品质的影响

目的研究日晒、加热浓缩结晶和电渗析脱盐技术对酱油品质的影响,研制高效实用的酱油脱盐工艺。方法以氨基酸态氮、可溶性无盐固形物、游离氨基酸含量和感官评分作为指标,比较不同工艺制备的低盐酱油的营养与感官品质。结果日晒浓缩结晶、加热浓缩结晶和电渗析处理酱油的脱盐速率分别为0.22%/h、0.41%/h和21%/h,可溶性无盐固形物损失率分别为22.44%±2.23%、4.62%±0.67%和68.61%±1.07%,相应的感官评分为25.8、28.8和23.1(原酱油为27.2)。日晒浓缩结晶和电渗析脱盐酱油的氨基酸态氮损失率分别为4.65%±0.47%和28.51%±0.52%,总游离氨基酸损失率为36.24%±1.35%和64.34%±0.54%;而加热浓缩结晶脱盐的氨基酸态氮和总游离氨基酸增加了14.17%±0.43%和78.35%±3.02%。结论采用日晒和加热浓缩结晶脱盐制备低盐酱油速率较慢,但其氨基酸态氮、可溶性无盐固形物和游离氨基酸的损失率明显比电渗析的低,且综合感官质量更好。本研究结果可为酱油及其他食品的脱盐提供参考,有利于解决因高盐饮食引起的健康问题。

Hot deformation behavior of Fe-29Ni-17Co alloy

Hot compression tests were carried out on a Fe-29Ni-17Co alloy in the temperature range of 900 ℃ to 1200 ℃ and at strain rates of 0.001-1 s-1. Dynamic recrystallization was found responsible for flow softening during hot compression. The flow behavior was successfully analyzed by the hyperbolic sine equation and the corresponding material constants A, n and αwere determined. The value of apparent activation energy was determined as 423 kJ/mol. The peak and steady state strains showed simple power-law dependence on the Zener-Hollomon parameter. The dynamic recrystallization kinetics was analyzed using Avrami equation and the corresponding exponent was determined to be about 2.7. This value, higher than 2 reported in the literatures, is associated with the mechanism of continuous dynamic recrystallization in the studied alloy. The flow curve up to the peak was modeled by the Cingara equation and the strain exponent, c, was determined about 0.85. The higher value of c compared with the value of 0.2 which has been reported for some stainless steels fortified the idea of extended dynamic recovery or continuous dynamic recrystallization in the studied alloy.

Microstructure evolution and hot deformation behavior of Cu–3Ti–0.1Zr alloy with ultra-high strength

The hot compression deformation behavior of Cu−3Ti−0.1Zr alloy with the ultra-high strength and good electrical conductivity was investigated on a Gleeble−3500 thermal-mechanical simulator at temperatures from 700 to 850℃ with the strain rates between 0.001 and 1 s^−1.The results show that work hardening,dynamic recovery and dynamic recrystallization occur in the alloy during hot deformation.The hot compression constitutive equation at a true strain of 0.8 is constructed and the apparent activation energy of hot compression deformation Q is about 319.56 kJ/mol.The theoretic flow stress calculated by the constructed constitutive equation is consistent with the experimental result,and the hot processing maps are established based on the dynamic material model.The optimal hot deformation temperature range is between 775 and 850℃ and the strain rate range is between 0.001 and 0.01 s^−1.

Hydrothermal preparation and crystal habit of X-zeolite powder

The preparation of X-zeolite powder was investigated in hydrothermal system, the crystal growth process of X-zeolite in hydrothermal condition was characterized by means of X-ray diffraction, scanning electron microscope and infrared ray. The results show that X-zeolite powder with uniform granularity and intact crystal shape can be obtained in hydrothermal system of acid-treated stellerite KG-*5CD*2KG-*9NaOHKG-*5CD*2KG-*9NaAl（OH）4KG-*5CD*2KG-*9H2O; the crystallite size is in the range of 2CD*23μm. The best reaction time of hydrothermal preparation is 6h. The formation phases of X-zeolite crystal are as follows: dissolution of feedstocks → formation of [SiO4] 4- and [AlO4] 5- tetrahedron, many-membered ring, β cage → formation of crystal nucleus and nano-particle → aggregation growth of nano-particle → coalescence growth of crystallite. The crystal habits of X-zeolite are intimately related with crystallization orientation of β cage in crystal and with its coupling stability on every crystal face family.

Evolution of microstructure, phase composition, and tensile properties of severely cold deformed titanium metastable β alloy in rapid continuous heating

Influence of severe cold deformation of titanium alloy Ti-1.5%A1-6.8%Mo-4.5%Fe in metastable β condition on the evolution of phase composition, microstructure, and tensile properties during continuous rapid heating was studied. As-deformed alloy was characterized by quasi-amorphous single-phase β condition with an abnormal temperature dependence of electric resistance that was normalized after 48 h exposure at room temperature as a result of isothermal ω phase precipitation. Subsequent rapid heating with a rate of 5 ℃/s caused recovery and recrystallization. Tensile properties of the alloy after different treatments were determined and discussed.

Microstructure evolution and optimum parameters analysis for hot working of new type Mg-8Sn-2Zn-0.5Cu alloy

The hot deformation behavior of as-solutionized Mg 8Sn 2Zn 0.5Cu(TZC820)alloy was investigated experimentally and numerically via isothermal compression tests at 250400℃and strain rate range of 0.013 s 1 on a Gleeble 1500D thermomechanical simulator.Results show that the deformation temperature and strain rate signi cantly affected ow stress and material constants.In addition,the strain-compensated constitutive relationship was established on the basis of true stress strain curves.The main deformation mechanism for this alloy was the dynamic recrystallization(DRX),and the DRX degree was effectively enhanced with an increase in deformation temperature and a decrease in strain rate.Moreover,the cellular automaton method was used to simulate the microstructure evolution during hot compression.In addition,the processing maps were established,and the optimum deformation parameters for the as-solutionized TZC820 alloy are at 370400℃and 0.01 s 1,and at 320360℃and 13 s 1.

Hot working characteristics of HEXed PM nickel-based superalloy during hot compression

To study the hot deformation behavior of a new powder metallurgy nickel-based superalloy,hot compression tests were conducted in the temperature range of 1020−1110℃ with the strain rates of 0.001−1 s^−1.It is found that the flow stress of the superalloy decreases with increasing temperature and decreasing strain rate.An accurate constitutive equation is established using a hyperbolic-sine type expression.Moreover,processing map of the alloy is constructed to optimize its hot forging parameters.Three domains of dynamic recrystallization stability and instability regions are identified from the processing map at a strain of 0.7,respectively.The adiabatic shear band,intergranular crack and a combination of intergranular crack and wedge crack are demonstrated to be responsible for the instabilities.Comprehensively analyzing the processing map and microstructure,the optimal isothermal forging conditions for the superalloy is determined to be t=1075−1105℃ andε&=10^−3−10−2.8 s^−1.

Kinetics for static recrystallization after hot working of 0.38C-0.99Cr-0.16Mo steel

The restoration mechanisms for static recrystallization of work-hardened austenite were investigated by using double-pass compression tests performed on medium-carbon steel containing chromium and molybdenum. The softening fraction was defined by 2% offset method. The results show that Avrami exponent of about 0.21 is insensitive to deformation temperature, indicating that the action of steel grade should be considered. The time of 50% recrystallization (t0.5) decreases noteworthily with the increase of deformation temperature. Apparent activation energy for static recrystallization of 195 kJ/mol, which is close to that of vanadium microalloyed steel, is obtained by calculating. The increasing trend of the driving force for recrystallization is opposite to that of the deformation temperature, which is attributed to the number of operative slip system increasing as temperature increasing.

Hot workability and dynamic recrystallization mechanisms of pure nickel N6

The hot workability and dynamic recrystallization(DRX)mechanisms of pure nickel N6 were systematically investigated using hot compression tests.Based on hot compression data,the constitutive equation of N6 was developed and its reliability was verified.Its hot processing map was constructed,and combined with microstructural observations,a semi-quantitative response relationship between hot deformation parameters and microstructure was established.The DRX process of N6 is a thermally activated process and particularly sensitive to the strain rate.The optimal hot processing parameters for N6 were determined to be 950−1050℃ and 0.1−1 s^(−1).Furthermore,it was proven that the dominant nucleation mechanism is discontinuous DRX characterized by grain boundary bulging and twins assisting nucleation,while the continuous DRX characterized by subgrains combined with rotation is an inactive nucleation mechanism.

Processing map and microstructure evaluation of AA6061/Al_2O_3 nanocomposite at different temperatures

Hot compression behavior of Al6061/Al2O3nanocomposite was investigated in the temperature range of350-500°C andthe strain rate range of0.0005-0.5s-1,in order to determine the optimum conditions for the hot workability of nanocomposite.Theactivation energy of285kJ/mol for the hot compression test is obtained by using hyperbolic sine function.By means of dynamicmaterial model(DMM)and the corresponding processing map,safe zone for the hot workability of AA6061/Al2O3is recognized attemperature of450°C and strain rate of0.0005s-1and at temperature of500°C and the strain rate range of0.0005-0.5s-1,with themaximum power dissipation efficiency of38%.Elongated and kinked grains are observed at400°C and strain rate of0.5s-1due tothe severe deformation.

Hot forging of Mg-4Al-2Ba-2Ca(ABa X422) alloy and validation of processing map

A cup-shaped component of Mg-4 Al-2 Ba-2 Ca（ABa X422） alloy was forged in the temperature range of 300-500 °C and at speeds in the range of 0.01-10 mm/s with a view to validate the processing map and study the microstructural development. The process was simulated through finite-element method to estimate the local and average strain rate ranges in the forging envelope. The processing map exhibited two domains in the following ranges：（1） 300-390 °C and 0.0003-0.001 s^-1, and（2） 400-500 °C and 0.0003-0.3 s^-1 and both represented dynamic recrystallization（DRX）. The map revealed a wide flow instability regime at higher strain rates and temperatures lower than 400 °C, in which flow localization occurred. Forgings produced under conditions of the above two domains were sound and symmetrical, and had finer grain sizes when being forged in the first domain. However, when being forged in the flow instability regimes, the alloy fractured before the final shape was reached. The experimental load-stroke curves for the conditions within the domains correlated well with the simulated ones, whereas the curves obtained in the instability regime were uneven.

Influence of Holding Time on Hot Deformation Behavior of Hard-Deformed Superalloy U720Li

To improve the hot workability of hard-deformed superalloy U720Li,the effect of holding time before deformation(5 and 10 min)on hot deformation behavior was investigated by hot compression tests.Results show that the flow stress increases with increase in strain rate,while decreases with increase in deformation temperature and holding time.Based on the obtained Arrhenius-type constitutive models,the calculated peak stresses are in good agreement with experimental values,indicating that this model can accurately predict the hot deformation behavior of U720Li alloy,and the deformation activation energies for the holding time of 5 and 10 min were calculated to be 992.006 and 850.996 kJ·mol^(-1),respectively.Moreover,processing maps of U720Li alloy with these two holding durations were constructed.Through observation of deformation microstructures in each domain of the processing maps,the optimal hot working conditions for the holding time of 5 min are determined to be 1090‒1110℃/1‒10 s^(-1) and 1146‒1180℃/1‒10 s^(-1),and the optimal hot working conditions for the holding time of 10 min are 1080‒1090℃/1‒10 s-1 and 1153‒1160℃/1‒10 s^(-1),indicating that the safe processing window can be obviously enlarged by shortening the holding time reasonably.In the absence of cracking,the dynamic recrystallization(DRX)grain size increases gradually with increasing the deformation temperature and holding time,but it first decreases and then increases with the increase in strain rate.When the deformation temperature is below 1100℃,the DRX mechanism is mainly the particle-induced continuous DRX.As the temperature is raised to above 1130℃,the main DRX mechanism changes to discontinuous DRX.