连铸轴承钢坯的轧后控冷工艺

国内某特钢厂在连铸连轧生产线上,用250 mm×280 mm连铸GCr15轴承钢方坯直接轧制直径22-100 mm圆钢.为了控制轴承钢轧后的网状碳化物,以现场取样的方坯为研究对象,利用MMS-200热模拟实验机进行模拟实验,分析了1 000 ℃终轧后的显微组织,得出以大于5 ℃/s的冷速控冷可以抑制粗大网状组织的产出.借助ANSYS有限元分析软件,讨论了在现有生产线上实现抑制网状碳化物析出的可行性.     

大断面轴承钢控轧控冷工艺的模拟与分析

利用Gleeble 1500热模拟实验机,研究了轴承钢在850℃终轧后,不同冷却速度对其显微组织结构的影响规律.采用ANSYS有限元软件,模拟了大断面轴承钢在不同工艺制度下的温度场分布.结果表明:冷却速度是影响轴承钢碳化物析出的主要因素,在850℃终轧变形后,为了抑制网状的析出,冷却速度应达到3℃/s左右为宜;轴承钢断面越大,在快速冷却过程中,表面与心部的温度差越大(最大温差约450℃),心部冷却越困难;直径为60 mm以下圆钢,通过冷却强度与冷却制度的合理匹配,可以控制心部的冷速达到3℃/s,从而抑制网状碳化物析出.     

穿水冷却对GCr15轴承钢组织和力学性能的影响

通过4种穿水冷却工艺生产20mm热轧GCr15轴承钢棒材,研究了穿水冷却对热轧及球化退火、淬回火热处理后轴承钢组织和力学性能的影响.结果表明:终轧前后均采用穿水冷却,控制终轧温度在800~860℃,上冷床返红温度为620℃,能明显降低先共析碳化物及珠光体相变温度,减小热轧轴承钢中先共析碳化物厚度、连续度及珠光体片层、球团大小.退火及回火组织中碳化物厚度减小,均匀性增加,防止了粗大未溶网状碳化物的遗传.热轧及热处理后轴承钢抗拉强度及面缩率均增强.     

高温变形GCr15连续冷却相变及显微组织分析

为合理确定GCr15轴承钢的轧后冷却工艺,利用Gleeble1500热模拟实验机,模拟830℃终轧的变形过程,测定GCr15轴承钢的动态CCT曲线;利用光学显微镜、扫描电镜等分析了冷却速度对珠光体片层厚度和网状碳化物析出的影响规律.实验结果表明:在一定的冷却速度范围内,随着冷速的增加珠光体片层变薄,当冷却速度过大时,会产生一种粗大的类珠光体组织;当冷却速度为10℃/s左右时,可以获得细片状珠光体组织,且可有效减少网状碳化物的析出.     

大断面轴承钢轧后控冷工艺的数值模拟分析

大断面轴承钢棒材轧制后,冷却速度过小心部易出现网状碳化物;冷却速度过大棒材表面容易形成马氏体,导致表面出现裂纹。为了分析轴承钢内部温度场变化规律,获得制定合理冷却工艺的依据,利用ANSYS有限元模拟软件对直径80mm GCr15轴承钢棒材轧后冷却过程温度场进行仿真,结果表明:80mmGCr15轴承钢棒材表面最低温度是379℃,经历80s后心部温度降到650℃,心部最大平均温降速度为3.13℃/s。最佳冷却工艺为:水冷3s+空冷5s+水冷3s+空冷8s+水冷5s+空冷10s+水冷5s+空冷。     

轴承钢棒材超快速冷却的试验研究

在特殊钢棒材厂原有连轧生产线上,通过增设超快速冷却系统,对轴承钢棒材高温终轧后进行超快速冷却工业试验.在连轧机组后增设三组超快速冷却系统.通过调节水压、喷嘴孔大小以及开启水箱个数,对GCr15轴承钢棒材进行高温终轧后超快速冷却.结果表明:随着连续冷却速度增加,晶界处二次碳化物中C,Cr含量减小,珠光体球团直径和片层间距减小,显微硬度值增大.棒材断面不同位置的冷却速度均可以达到抑制网状碳化物析出、过冷奥氏体完全发生珠光体转变的冷却速度要求,网状碳化物级别小于2级,达到轴承行业标准.     

轴承钢水冷的实验模拟研究

针对大端面轴承钢在轧后冷却过程中由于冷速过慢引起碳化物网状不合问题,利用实验室自制设备,对从现场剪取的轧材进行了模拟实验研究.记录了不同断面、不同冷却条件下的轧材径向温度变化趋势,提出合理的冷却制度,不同直径的圆钢心部温度降速在1.5-6 ℃/s变化,直径越小,降速越大.为进一步工艺设计和计算机模拟研究提供了依据.     

轴承钢水冷的实验模拟研究

针对大端面轴承钢在轧后冷却过程中由于冷速过慢引起碳化物网状不合问题，利用实验室自制设备，对从现场剪取的轧材进行了模拟实验研究．记录了不同断面、不同冷却条件下的轧材径向温度变化趋势，提出合理的冷却制度，不同直径的回钢心部温度降速在1．5—6℃/s变化，直径越小，降速越大。为进一步工艺设计和计算机模拟研究提供了依据。     

超快冷终冷温度对轴承钢棒材组织性能影响

以GCr15轴承钢棒材为研究对象,研究了超快速冷却终冷温度对其组织性能的影响.研究发现:高温终轧后以大于100℃/s的冷却速度超快速冷却到一定温度后缓冷到室温,随着超快冷段终冷温度降低,珠光体球团直径和片层间距减小;终冷温度过高只能使晶界碳化物厚度减薄但不能抑制其呈网状析出,降低终冷温度到715℃以下就可以得到抑制了网状碳化物析出的细片层珠光体型组织;随着终冷温度继续降低显微硬度增加并有退化珠光体产生,其显微硬度可达到426 HV.     

浅谈高碳铬轴承钢的热处理

高碳铬轴承钢在热处理时对碳化物、脱碳程度等项要求严格。所以钢锭在加热时要注意碳化物高温扩散及脱碳问题,为保证碳化物扩散,采用高温扩散退火以减少偏析级别,但为了降低脱碳应适当降低加热温度和缩短在高温带的停留时间;钢坯成材轧后快速冷却,以避免网状碳化物的形成,以利于后续的球化退火,满足切削加工及冷加工的要求。     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3～4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰～ -7.8‰, PDB) and matrix dolomites (-6.6‰～ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084～0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078～0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.     

Design and analysis of generic LBS application developing platform

Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.     

橡胶颗粒沥青混合料低温抗裂性试验研究

以AC-13级配为基础,将橡胶颗粒代替部分集料掺入混合料中,以低温弯曲试验为评价方法对不同橡胶颗粒掺量下沥青混合料的低温抗裂性进行研究,并引入应变能密度值对混合料的低温抗裂性进行综合评价.试验结果表明:橡胶颗粒沥青混合料试件的破坏微应变均超过2 300,满足冬寒区的技术指标;无论是否掺加橡胶颗粒,随着温度的下降,沥青混合料破坏时的最大弯拉强度增大,弯拉应变降低,劲度模量增大;弯曲应变能密度在胶粒掺量为1%左右时具有较大的弯曲应变能密度值,此时橡胶颗粒沥青混合料具有较好的低温抗裂性.     

A computer generator for randomly layered structures

AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

Quantitative trait loci （QTLs） for quality traits related to protein and starch in wheat

Quality traits in wheat （Triticum aestirum L.） were studied by quantitative trait locus （QTL） analysis in a recombinant inbred line （RIL） population, a set of 131 lines derived from Chuan 35050 × Shannong 483 cross （ChSh）. Grains from RILs were assayed for 21 quality traits related to protein and starch. A total of 35 putative QTLs for 19 traits with a single QTL explaining 7.99-40.52% of phenotypic variations were detected on 10 chromosomes, 1D, 2A, 2D, 3B, 3D, 5A, 6A, 6B, 6D, and 7B. The additive effects of 30 QTLs were positive, contributed by Chuan 35050, the remaining 5 QTLs were negative with the additive effect contributed by Shannong 483. For protein traits, 15 QTLs were obtained and most of them were located on chromosomes 1 D, 3B and 6D, while 20 QTLs for starch traits were detected and most of them were located on chromosomes 3D, 6B and 7B. Only 7 QTLs for protein and starch traits were co-located in three regions on chromosomes 1D, 2A and 2D. These protein and starch trait QTLs showed a distinct distribution pattern in certain regions and chromosomes. Twenty-two QTLs were clustered in 6 regions of 5 chromosomes. Two QTL clusters for protein traits were located on chromosomes 1D and 3B, respectively, three clusters for starch traits on chromosomes 3D, 6B and 7B, and one cluster including protein and starch traits on chromosome 1D.     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.