低成本汽车结构钢SAPH400的研发

介绍了唐钢1 580 mm生产线开发低成本汽车结构钢SAPH400的成分设计、工艺路线、及产品性能情况。通过重新设计炼钢成分,降低Mn含量;轧钢过程中利用控轧控冷工艺,合理设计热轧温度制度及冷却策略,提高热卷强度,达到SAPH400标准要求。开发出利用"水代合金"技术,在满足汽车结构钢SAPH400的性能要求的同时,降低生产工艺成本,提高产品效益,成功研发低成本汽车结构钢SAPH400。     

热轧酸洗板SAPH370冲压汽车底梁回弹原因分析及解决方案

邯钢生产的汽车结构用热轧酸洗板SAPH370应用于某品牌乘用车底梁,但在冲压过程中出现回弹倾向严重的问题,为此进行化学成分、力学性能、显微组织等对比分析。结果表明,SAPH370钢的屈服强度和抗拉强度明显高于某钢厂,断后延伸率较某钢厂偏低;屈服强度偏高是导致回弹倾向严重的根本原因。采取优化热轧工艺、降低强度、提高断后延伸率的方法,成功解决了SAPH370钢板冲压汽车底梁回弹问题。     

X100管线钢开发实践

根据高强度管线钢发展趋势,参考API SPEC 5L-2007《管线钢管规范》和中国石油天然气集团公司《天然气输送管道X100钢级螺旋缝埋弧焊管用热轧板卷技术条件》要求,邯钢公司制定了X100管线钢热轧卷板生产试制的技术要求。通过化学成分、冶炼、控轧控冷工艺设计,邯钢公司试制生产的X100管线钢在2250热连轧生产线热轧卷板具有较高的强度和良好的低温韧性,金相组织检验为"板条贝氏体+粒状贝氏体"组织,产品的各项力学性能达到了设计要求。     

邯钢X70管线钢热轧板卷的生产实践

介绍了邯钢X70管线钢热轧板卷的工艺设计以及工业生产情况,对生产过程中出现的屈服强度偏低问题进行了分析和改进。     

汽车结构用热轧钢SAPH370的组织与性能

介绍了武钢研发的汽车结构用热轧钢SAPH370的化学成分、性能指标,并对其实物质量进行检验分析。结果表明,SAPH370钢金相组织为铁素体和珠光体,钢质纯净、晶粒细小、具有优良的冷成形性和良好的综合力学性能,加上优异的表面质量,已成功应用于汽车车架等高成型性零件。     

板坯边裂原因分析与控制

热轧板卷边裂是常见的质量缺陷。介绍了邯钢2250热轧生产线板坯边裂的形貌特征及分布规律。分析了边裂产生的原因主要是夹渣和夹杂造成的。通过建立和完善《热轧板卷边裂图谱》,有针对性地指导炼钢生产,边裂缺陷率由3.0%以上减少到0.4%以下,降级改判损失明显减少。     

含微量钒钛的Q345R钢的研制与生产

介绍了首钢迁钢公司通过应用微量钒钛复合微合金化和控轧控冷技术研制与生产Q345R热轧板卷的情况,分析了批量生产的Q345R热轧板卷的化学成分、冶金质量和力学性能。结果表明:对0.17%C-0.35%Si-1.40%Mn化学成分体系的低碳锰钢进行微量钒钛复合微合金化(w(V)≤0.025%,w(Ti)≤0.025%),可以开发生产出符合国家标准和用户需求的Q345R热轧板卷;复合添加的微量V,Ti元素对Q345R热轧板卷的显微组织影响很小,细晶强化作用不明显,但是能够产生明显的沉淀强化作用。     

SAPH440钢板冲压开裂原因分析

利用金相显微镜、扫描电镜对SAPH440冲压开裂钢板进行分析,分析结果表明,钢板中混晶及珠光体偏析带的存在,加上晶界上析出渗碳体的共同作用导致钢板在冲压时发生开裂。     

CSP连铸薄板坯中非金属夹杂物行为研究

通过在炼钢和连铸过程的各个阶段加入不同的示踪元素,采用金相观察、大样电解、电子探针及扫描电镜等多种方法对邯钢CSP流程低碳铝镇静钢中非金属夹杂物行为进行了调查研究,找出了夹杂物的来源、数量及分布的变化规律.研究表明CSP薄板坯的洁净度水平低于传统板坯,在相同的钢种和热轧板厚条件下,邯钢CSP热轧板卷生产的冷轧板缺陷率比传统工艺热轧板卷生产的冷轧板缺陷率高62%.对结晶器EMBr实际使用效果研究表明,无电磁制动时,结晶器液面波动为±7 mm,使用电磁制动时,结晶器液面波动为±4 mm,钢中w(TO)降低了40%,大型夹杂物减少了61%.应用CFX软件数学模拟了电磁制动及无电磁制动情况下的CSP结晶器流场.模拟结果表明,在邯钢现行工艺条件下,结晶器使用电磁制动后,结晶器弯月面钢水中心线速率降低了约3倍,湍动能降低了2倍左右.结晶器钢水流动减缓,结晶器钢水卷渣明显减轻,薄板坯洁净度明显改善.     

CSP酸洗钢SAPH370的冷却工艺优化

 屈强比偏高是CSP产品的共性问题。为降低CSP酸洗钢SAPH370的屈强比,采用正交化试验设计,研究了两段冷却工艺参数终轧温度、空冷起始温度和卷取温度对屈强比的影响。对试验结果进行统计,并利用光学显微镜分析了不同工艺条件下SAPH370钢的相组成和晶粒尺寸。研究结果表明,空冷起始温度和卷取温度对屈强比的影响显著。空冷起始温度由740℃提高到760℃,可降低屈强比0.017;卷取温度由500℃提高到560℃,可降低屈强比0.015;而终轧温度对屈强比的影响不太明显,终轧温度由860℃提高到880℃,屈强比仅降低0.005。采用两段冷却工艺,通过调整空冷起始温度和卷取温度可有效降低酸洗钢SAPH370的屈强比。     

降低武钢CSP低碳酸洗钢SAPH370屈强比的实践

屈强比偏高是CSP低碳产品的共性问题。为降低CSP低碳酸洗钢SAPH370的屈强比,采取了不同轧制工艺(终轧温度FT7、卷取温度CT和冷却方式)进行试验,对不同工艺下的低碳酸洗钢的力学性能、晶粒尺寸和相组成进行了对比分析。结果表明:SAPH370钢采用终轧温度(FT7)为860℃、卷取温度(CT)600℃、后段快速冷却的工艺,在满足强度要求的前提下,屈强比可降低到0.8以下。观察到铁素体晶粒粗化、珠光体弥散分布。分析表明:CSP采用后段快冷工艺与传统热连轧的两段冷却工艺相当,有利于获得合适的铁素体晶粒度和弥散分布的珠光体。     

多元光谱拟合校正电感耦合等离子体原子发射光谱法测定铑粉中19种杂质元素

建立了一种用电感耦合等离子体原子发射光谱法(ICP-AES)测定铑粉中Pt、Pd、Ru 、Ag、Cu、Fe、Zn、Ni、Mn、Mg、Al、Ca、Sn、Ir、Na、Au、Si、Pb、K 等19种杂质元素的方法。以HCl和H₂O₂作为消解试剂, 微波法消解试样, 然后采用ICP-AES法测定消解液中19种杂质元素。基体铑对Pt、Ir、Au产生的光谱干扰采用多元光谱拟合(MSF)方法校正, 基体效应采用仪器自动扣背景方法消除, 杂质元素间没有干扰。方法的检出限(μg/mL)为0.051(Pt)、0.008 0(Pd)、0.015(Ru)、0.008 5(Ag)、0.007 9(Cu)、0.015(Fe)、0.032(Zn)、0.035(Ni)、0.007 5(Mn)、0.005 5(Mg)、0.006 6(Al)、0.030(Ca)、0.035(Sn)、0.030(Ir)、0.013(Na)、0.026(Au)、0.045(Si)、0.025(Pb)和0.005 7(K), 加标回收率在88.1%~112.3%之间, 相对标准偏差(RSD)在1.7% ~5.2%范围。方法已用于实际样品的分析。     

Beyond a stereotyped view of older adults' traditional family values.

Structural equation models for predictors of traditional family values regarding relationships were examined in 2 samples: undergraduate students and adults ranging widely in age (23–86 yrs). Predictor variables included verbal ability, need for cognition, need for closure, intolerance for ambiguity, religiosity, and gender orientation. The models accounted for a substantial proportion of the variance in traditional family values (64% for students, 63% for adults). Findings provide little support for common stereotypes regarding age and gender differences in traditionalism. Instead, 3 individual-differences variables predicted traditional family values: need for closure, religiosity, and verbal ability. Outcomes argue for the need to identify multiple mechanisms by which personal characteristics such as need for closure and religiosity influence traditionalism in social belief systems and argue against reliance on status variables such as age and gender as explanatory variables for these beliefs. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Application of Rare Earth Phosphate Fertilizer in Western Area of China

Rare earth phosphate fertilizer (REPF) as base fertilizer (750 kg per hm2) was applied in the western area of China during the "Tenth Five-Year Plan", and the results show as follows: compared with calcium superphosphate (CK), REPF increases crops yields for maize by 17.0%, for rice by 10.5%, for wheat by 24.2%, for potato by 18.5%, for cabbage by 16.3%, for Chinese cabbage by 16.4%, for beet by 6.5%; decreases the diseased plant rate for common smut of maize by 1.0%, for maize stalk rot by 1.2%, for wheat take-all disease by 7.8%, for wheat root rot by 3.2%, for potato blackleg disease by 1.4%, for potato late blight by 6.6%; increases the sugar content of beet by 0.9°S.     

Semantic priming from letter-searched primes occurs for low- but not high-frequency targets: Automatic semantic access may not be a myth.

[Correction Notice: An erratum for this article was reported in Vol 34(1) of Journal of Experimental Psychology: Learning, Memory, and Cognition (see record 2007-19381-019). In the article "Semantic Priming From Letter-Searched Primes Occurs for Low- but Not High- Frequency Targets: Automatic Semantic Access May Not Be a Myth," by Chi-Shing Tse and James H. Neely (Journal of Experimental Psychology: Learning, Memory, and Cognition, 2007, Vol. 33, No. 6, pp. 1143-1161), the URL for the supplemental materials was incomplete. The complete URL is http://dx.doi.org/10.1037/0278-7393.33.6.1143.supp] Letter-search (LS) within a prime often eliminates semantic priming. In 2 lexical decision experiments, the authors found that priming from LS primes occurred for low-frequency (LF) but not high-frequency (HF) targets whether the target's word frequency was manipulated between or within participants and whether the prime-target pairs were associated symmetrically or forward asymmetrically. For the LF targets, LS priming was (a) equivalent for forward asymmetric and symmetric pairs and (b) equal to silent-read (SR) priming for forward asymmetric pairs but less than SR priming for symmetric pairs. The typical finding of greater SR priming for response times for LF than for HF targets occurred for symmetric priming but not for forward asymmetric priming, which showed the interaction for errors. The authors consider their findings' implications for various accounts of how LS affects priming and explain the findings within J. H. Neely and D. E. Keefe's (1989) 3-process model as follows: (a) LS eliminates expectancy and semantic matching but does not reduce semantic activation and (b) expectancy contributes to SR priming for HF targets but not for LF targets, whereas the opposite is so for semantic matching. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Experience of Improving Standards and Methods for Studying the Properties of Metal Powders and Sintered Articles

Reasons are considered for improving standards in the following methods for testing powder materials: tensile, transverse bending, gas and liquid permeability, and determination of powder compact dimensions after compaction pressure removal and during sintering. Calculated data for representative specimen dimensions (cross section and thickness) for these and other test methods for sintered articles (materials) prepared from mono- and polyfraction iron powder of different sizes are confirmed by experiment. It is shown that the representative specimen dimensions prepared from monofraction powder are more than an order of magnitude less than for those prepared from polyfraction powder. The reason for this difference is considered to be the special role of individual particles (for monofraction powder) or assemblies of these particles (for polyfraction powder) in forming elementary fragments within the structure of compacts and sintered articles. Data are provided for the improved ISO 4492-1985 standard and a new GOST 29012-91 standard developed on the basis of it for precise determination of changes in the dimensions of powder compacts during pressing and sintering. Use of this method makes it possible to reveal the existence of different structural states within narrow porosity limits for powder materials. It is shown by experiment that the pulsed ultrasonic method for monitoring these structural states based on measuring the propagation rate and (or) the elastic wave damping factor, exhibits high sensitivity, it is rapid, and it may be recommended for extensive introduction and standardization in powder metallurgy.     

宣钢150t转炉长寿技术创新

分析了溅渣转炉炉衬的主要破坏机理,阐述了宣钢150 t转炉炉衬维护在应对各种形式的侵蚀时采用的创新性技术。系统地介绍了溅渣护炉技术的合理应用,炉帽部位的长寿技术,受料面长寿技术,出钢口部位的维护技术,炉底底吹元件长寿技术,综合炉衬指标的优化等关键的技术情况。为大型转炉长寿技术的发展提供了借鉴。     

锍试金富集-电感耦合等离子体质谱法测定地质样品中铂钯铑铱

建立了锍试金富集电感耦合等离子体质谱法(ICP-MS)测定地质样品中铂、钯、铑、铱的新方法。样品用硫化镍富集,酸处理除去碱金属硫化物,过滤,残渣用盐酸和过氧化氢溶解,ICP-MS法测定。研究了富集时各种因素的影响。方法检出限:Pt为0.11ng/g,Pd为0.038ng/g,Rh为0.016ng/g,Ir为0.040ng/g;相对标准偏差(n=12):Pt为4.09%,Pd为4.75%,Rh为4.53%,Ir为4.78%。测定了国家一级地球化学标准物质中痕量Pt,Pd,Rh,Ir,结果与认定值相吻合。     

Resistance Factors for Use in Shallow Foundation LRFD

In shallow foundation design, the key improvements offered by LRFD over the traditional working stress design (WSD) are the ability to provide a more consistent level of reliability between different designs and the possibility of accounting for load and resistance uncertainties separately. In the development of LRFD, a framework for the objective, logical assessment of resistance factors is needed. Additionally, in order for LRFD to fulfill its promise for designs with more consistent reliability, the methods used to execute a design must be consistent with the methods assumed in the development of the LRFD factors. In this paper, a methodology for the estimation of soil parameters for use in design equations is proposed that should allow for more statistical consistency in design inputs than is possible in traditional methods. Resistance factors for ultimate bearing capacity are computed using reliability analysis for shallow foundations both in sand and in clay, with input parameters obtained from both the cone penetration test and the standard penetration test, and for both ASCE-7 2000 and AASHTO 1998 load factors. Resistance factor values are dependent upon the values of load factors used. Thus, a method to adjust the resistance factors to account for code-specified load factors is also presented.