共查询到19条相似文献，搜索用时 171 毫秒
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相变诱导塑性钢生产现状与发展趋势 总被引：2，自引：0，他引：2
通过相变诱导塑性(transformation induced plasticity,TRIP)效应使钢板中残余奥氏体在塑性变形作用下发生马氏体相变,TRIP钢以其高强度、优异的成形性能成为近年来汽车用钢研究的热点。概述了相变诱导塑性(TRIP)钢的理论研究现状,讨论了其化学成分、微观组织形态、残余奥氏体含量等因素对材料性能的影响。介绍了国内外TRIP钢工业应用情况,并对TRIP钢的发展趋势做了展望。 相似文献
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采用常规点焊工艺,对用于生产TRIP700及DP700汽车板的1.5mm厚的高Al高强钢冷轧原板进行了电阻点焊试验,得到了合格的点焊强度及破裂模式,说明其有良好的电阻焊性能。焊点的金相组织为马氏体。剥离试验与拉剪试验焊点失效模式有一定的差异。该钢合金含量较高,点焊工艺窗口较窄。 相似文献
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综合原子半径，钻穿效应，镧系收缩等理论，以氮族元素为例，从原子结构角度，分析产生“惰性电子对效应”的原因。 相似文献
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王璟琳 《雁北师范学院学报》1995,(6)
本文论述了相对论效应在原子体系中是普遍存在的.相对论效应对元素性质特别是对重元素的性质有着显著的影响,例如,重元素中的一些“反常”的性质象镧系收缩、6S~2惰性电子对等与相对论效应有关,因此,在大学化学教学中应提及相对论效应. 相似文献
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阎翼明 《中学化学教学参考》1998,(7)
对教材中过渡元素种数的纠正四川省通江县第二中学阎翼明《高级中学课本化学（必修）第二册》（１９９５年１０月第２版）第４１面对过渡元素是这样叙述的：“我们从元素周期表上可以看到,表的中部从ⅢＢ族到ⅡＢ族１０个纵行,包括镧系和锕系,共有６３种元素,人们习惯... 相似文献
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对工业化生产的C-Mn-Al系高强度、高塑性冷轧钢板的组织和性能进行了研究,材料的抗拉强度为730MPa,屈服强度为470MPa,延伸率达到28%,屈强比为0.63;钢中的主要强化元素为C、Mn、Al,相应的最大含量分别小于0.21%、1.5%、1.6%,材料的原料成本低,生产工艺适应性好。 相似文献
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空间耦合效应对钢框架结构性能有显著影响,随着计算理论的深入和试验水平的不断提高,如何对钢框架进行空间效应的高等分析受到普遍关注.简要回顾了空间钢框架结构的研究历史,论述了近年来在分析方法、分析软件、抗火研究和结构试验等方面的主要进展,提出了空间钢框架研究尚存在的问题和将来的发展趋势. 相似文献
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Effects of finishing rolling temperatures and reduction on the mechanical properties of hot rolled multiphase steel were investigated. Thermo-mechanical control processing (TMCP) was conducted by using a laboratory hot rolling mill, in which three different kinds of finishing rolling temperatures and reduction and various austempering times were applied. The results showed that polygonal ferrite, granular bainite and larger amount of stabilized retained austenite can be obtained by controlled rolling processes, and that the strain-induced transformation to martensite from the retained austenite can occur gradually when the steel is deformed during tensile test. Mechanical properties increase with decreasing finishing rolling temperature and increasing amount of deformation. The most TRIP (transformation induced plasticity) effect, and ultimate tensile strength (UTS), total elongation (TEL) and the product of ultimate tensile strength and total elongation (UTS×TEL) are obtained at 20 min. 相似文献
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研究了三种外掺料对路面混凝土早期开裂性能的影响。通过理论分析, 将水泥路面的早期开裂机理归结为混凝土具有塑性收缩、自收缩和干缩等早期收缩性能; 采用室内试验分别研究了聚丙烯纤维、钢纤维和粉煤灰对混凝土早期收缩性能的改善效果。研究结果表明, 聚丙烯纤维和粉煤灰能够大幅度降低混凝土的早期收缩值, 钢纤维的改性作用则不明显。建议为全面评价不同混凝土的长期开裂性能, 应增加开裂后的疲劳和冲击试验研究。 相似文献
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无取向硅钢要求沿材料的所有方向都具有均匀的磁性能,即要求磁各向异性要尽可能地小,以便为旋转电机提供理想的磁性能。通过试验测试了3.0%Si无取向硅钢不同方向的磁感,铁损和磁致伸缩系数。实验结果表明55°和125°磁化轴为最难磁化轴,而0°和180°磁化轴为最易磁化轴,铁损的变化规律与磁致伸缩系数一致,即90°最大,0°和180°最小,采用相应的理论和数学模型能较好地进行模拟和解释实验结果。 相似文献
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一种水性可剥离涂料的研制 总被引：1，自引：0，他引：1
孙幼红 《南京晓庄学院学报》2006,22(6):101-103
某种液体橡胶可以作为水性可剥离涂料的成膜物质;该涂料适用范围广泛,可以从木材、钢铁、铝材、有机玻璃、聚乙烯、聚氯乙烯、玻璃等的表面顺利剥离;讨论了影响涂料性能的几个因素;该涂料涂膜的扯断强度大于15 Mpa,扯断伸长率约700%,撕裂强度约35KN/m. 相似文献
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桁架式结构因可提供较大的抗弯刚度,常常是大跨度结构的首选。基坑工程的围护桩是一种需要提供较大抗弯刚度用于承受横向力的受弯构件,桁架结构则是一种最合理的选择。液压高频振动锤可以提供较高的振动频率和激振力可确保在软土、砂砾和卵石层中将装配好的长方形空间桁架振动沉入地基中,使钢桁架桩在软土基坑中得以实施。与现今流行的支护结构相比,钢桁架桩可回收满足节能环保要求,结构受力明确,构件可在工厂进行标准化制作现场拼装,其质量可控,施工工期短,同时还可重复使用基坑监测测试原件。因此具有较高的经济与社会效益。 相似文献
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The market of stainless electric steel kettles is growing significantly, but the main mechanism for polishing kettles via traditional handwork operations limits the growth of electric kettle manufacturing. Based on the successful multi-tool automatic polishing system for electric stainless steel kettles, regression analysis and orthogonal tests were employed to construct a polishing process model, with a purpose to improve the automatic polishing technology for electric stainless steel kettles. The model reveals the relationship between the surface roughness and processing parameters including gringding depth, abrasive tangent speed, workpiece rotating speed and axial feeding speed. Simulation and experimental results are in agreement,which shows that this modeling method is feasible in practice, and it can also be used as a guidance for planning automatic polishing process of electric stainless-steel kettles. 相似文献
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Stephen Gorard 《International Journal of Research & Method in Education》2015,38(2):105-114
This paper revisits the use of effect sizes in the analysis of experimental and similar results, and reminds readers of the relative advantages of the mean absolute deviation as a measure of variation, as opposed to the more complex standard deviation. The mean absolute deviation is easier to use and understand, and more tolerant of extreme values. The paper then proposes the use of an easy to comprehend effect size based on the mean difference between treatment groups, divided by the mean absolute deviation of all scores. Using a simulation based on 1656 randomised controlled trials each with 100 cases, and a before and after design, the paper shows that the substantive findings from any such trial would be the same whether raw-score differences, a traditional effect size like Cohen's d, or the mean absolute deviation effect size is used. The same would be true for any comparison, whether for a trial or a simpler cross-sectional design. It seems that there is a clear choice over which effect size to use. The main advantage in using raw scores as an outcome measure is that they are easy to comprehend. However, they might be misleading and so perhaps require more judgement to interpret than traditional ‘effect’ sizes. Among the advantages of using the mean absolute deviation effect size are its relative simplicity, everyday meaning, and the lack of distortion of extreme scores caused by the squaring involved in computing the standard deviation. Given that working with absolute values is no longer the barrier to computation that it apparently was before the advent of digital calculators, there is a clear place for the mean absolute deviation effect size (termed ‘A’). 相似文献
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In this study, an artificial neural network （ANN） model for studying the strength properties of steel fiber reinforced concrete （SFRC） containing fly ash was devised. The mixtures were prepared with 0 wt%, 15 wt%, and 30 wt% of fly ash, at 0 vol.%, 0.5 vol.%, 1.0 vol.% and 1.5 vol.% of fiber, respectively. After being cured under the standard conditions for 7, 28, 90 and 365 d, the specimens of each mixture were tested to determine the corresponding compressive and flexural strengths. The pa- rameters such as the amounts of cement, fly ash replacement, sand, gravel, steel fiber, and the age of samples were selected as input variables, while the compressive and flexural strengths of the concrete were chosen as the output variables. The back propagation learning algorithm with three different variants, namely the Levenberg-Marquardt （LM）, scaled conjugate gradient （SCG） and Fletcher-Powell conjugate gradient （CGF） algorithms were used in the network so that the best approach can be found. The results obtained from the model and the experiments were compared, and it was found that the suitable algorithm is the LM algorithm. Furthermore, the analysis of variance （ANOVA） method was used to determine how importantly the experimental parameters affect the strength of these mixtures. 相似文献
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分析了板厚0.7mm的屈服强度180MPa级Nb超低碳烘烤硬化钢热轧及成品钢板的组织和织构,并进行了不同BH值钢板的常温时效实验。结果表明,试验钢板的成品晶粒度在8～9级有利于获得综合性能良好的烘烤硬化钢板,试验钢BH2值控制在35～50MPa的钢板综合性能最为理想。 相似文献