高碘酸钾法测钢铁及合金中锰的改进建议

试样经酸溶解后,以磷酸-高氯酸混合酸(4 1)或(9 1)氧化至冒烟.在硫酸、磷酸介质中,用高碘酸钾将锰氧化到七价,测其吸光度.     

Estimation of boron isotope ratios using high resolution continuum source atomic absorption spectrometry

In the production of ¹⁰B enriched steels, the production–recycling process needs to be closely monitored for inadvertent mix-up of materials with different B isotope levels. A quick and simple method for the estimation of boron isotope ratios in high alloyed steels using high resolution continuum source flame AAS (HR-CS-FAAS) was developed. On the 208.9 nm B line the wavelength of the peak absorption of ¹⁰B and ¹¹B differs by 2.5 pm. The wavelength of the peak absorption of boron was determined by fitting a Gauss function through spectra simultaneously recorded by HR-CS-FAAS. It was shown that a linear correlation between the wavelength of the peak absorption and the isotope ratio exists and that this correlation is independent of the total boron concentration. Internal spectroscopic standards were used to compensate for monochromator drift and monochromator resolution changes. Accuracy and precision of the analyzed samples were thereby increased by a factor of up to 1.3. Three steel reference materials and one boric acid CRM, each certified for the boron isotope ratio were used to validate the procedure.     

Three generations of inorganic phosphates in solvent and water-borne paints: A synergism case

This research work is intended to compare the anti-corrosive properties of three generations of inorganic phosphate pigments in solvent-based paints and in water-borne ones, both of the epoxy type. The anti-corrosive properties of phosphate pigments were assessed by means of electrochemical techniques (corrosion potential measurements, polarisation tests, etc.), employing a steel electrode dipped into pigments suspensions. The behaviour of these pigments in anti-corrosive paints, formulated with different binders, have been studied by accelerated (salt spray cabinet and humidity chamber) and electrochemical tests (corrosion potential and ionic resistance measurements).Accelerated and electrochemical tests allowed to differentiate the anti-corrosive performance of the three phosphates studied in this research. These test are also able to detect and characterise possible synergism between the water-borne resin and the pigments.     

Growth of carbon nanotubes from waste blast furnace gases at atmospheric pressure

Carbon emissions from industrial sources are of major global concern, especially contributions from the steel manufacturing process which accounts for the majority of emissions. Typical blast furnace gases consist of CO₂ (20‐25%), CO (20‐25%), H₂ (3‐5%) and N₂ (40‐50%) and trace amounts of other gases. It is demonstrated that gas mixtures with these compositions can be used at atmospheric pressure to grow carbon nanotubes (CNTs) by chemical vapor deposition (CVD) on to steel substrates, which act as catalysts for CNT growth. Computational modelling was used to investigate the CNT growth conditions inside the CVD chamber. The results show that industrial waste pollutant gases can be used to manufacture materials with significant commercial value, in this case CNTs.     

直读光谱法测定不锈钢中铬的不确定度评定

利用光电直读光谱仪测定不锈钢中铬含量,对其在测量过程中不确定度产生的原因进行了分析,并对测量结果的不确定度进行了评定。     

Evaluation of surface decarburization depth by magnetic Barkhausen noise technique

Industrially unfavorable process of steel surface decarburization was induced by annealing in air. Two methods of after-anneal surface treatment were used: an acid pickling and a sand blasting. The obtained decarburized layers were examined by optical microscope, wave dispersive spectrometer, and surface X-ray diffraction method. Magnetic Barkhausen noise technique was tested for applicability of non-destructive characterization of the decarburized layer depth. A newly introduced parameter, Barkhausen noise coercivity, was proposed for practical use due to its sensitivity to decarburization and stability to measurement conditions. Other magnetic parameters, e.g. number of Barkhausen noise counts, were found to be sensitive to the compressive residual stress caused by the sand blasting.     

Cost-effective modeling strategies for the analysis of spliced steel connections

The paper presents several cost-effective modeling strategies that can be used by structural engineers in practice to determine the stresses in the spliced members. The computational efficiency and the modeling effort required for the several modeling options are also discussed. The deformation mechanisms and load transfer for several types of connections are illustrated. Optimization techniques are also presented to economize the computer time for connections with large number of bolts. Results are presented to compare the accuracy of several modeling strategies commonly used in practice. It is shown that for eccentric connections, the flexural bending largely affect the maximum tensile and compressive stresses within the joint. The difference may reach up to 54%. Finally, Experimental comparisons are made with the numerical procedures for typical connection model.     

Effect of anisotropic microstructure on magnetic Barkhausen noise in cold rolled low carbon steel

We have measured the orientation and depth dependence of the magnetic Barkhausen noise (MBN) in an industrial pipeline steel sheet. Thin samples were cut out from the sheet cross section at different depths, parallel and transverse to the rolling direction (rolling and transverse samples). The integrated MBN energy has shown no depth dependence for transverse samples. On the other hand, the rolling samples have shown larger MBN noise energy and strong depth dependence.The microstructure of the samples was studied by optical and electron microscopy, parameters related to the shape and the quantity of carbon precipitates and grains were extracted by image processing techniques. The strong depth and orientation dependence of the MBN have been explained by changes of the grain and precipitate microstructure.     

钒(Ⅴ)-7-碘-8-羟基喹啉-5-磺酸显色体系测定钢样中的钒

研究了7-碘-8-羟基喹啉-5-磺酸（H2QSI）在乙醇存在下分光光度法测定钡（Ⅴ）的最佳条件。在乙醇存在下pH4的硫酸介质中,（H2QSI）与V（Ⅴ）形成了红棕色配合物,最大吸收位于506nm处,表观摩尔吸光系数εmax＝2.9×103L·mol-1·cm-1,有色配合物组成为V（Ⅴ）:（H2QSI）＝1:3。钒（Ⅴ）在0-14μg／25mL符合比耳定律、本法用于钢样中的测定,结果满意。H2QSI是光度分析中的一种显色剂,近年来,8-羟基喹啉类试剂用于钒（Ⅴ）的测定已有报道[1]:,H2QSI曾见用于稀土元素的光度测定[2],但用于钒（Ⅴ）的测定尚未见报道。本文研究了V（Ⅴ）与H2QSI的显色反应条件及组成,在pH4的乙醇介质中,V（Ⅴ）与H2QSI生成红棕色配合物ε506nm＝2.9×103L·mol-1·cm-1。本方法用于低碳合金钢中钒的测定,结果满意。     

A mathematical programming model and solution for scheduling production orders in Shanghai Baoshan Iron and Steel Complex

In this paper, we investigate the production order scheduling problem derived from the production of steel sheets in Shanghai Baoshan Iron and Steel Complex (Baosteel). A deterministic mixed integer programming (MIP) model for scheduling production orders on some critical and bottleneck operations in Baosteel is presented in which practical technological constraints have been considered. The objective is to determine the starting and ending times of production orders on corresponding operations under capacity constraints for minimizing the sum of weighted completion times of all orders. Due to large numbers of variables and constraints in the model, a decomposition solution methodology based on a synergistic combination of Lagrangian relaxation, linear programming and heuristics is developed. Unlike the commonly used method of relaxing capacity constraints, this methodology alternatively relaxes constraints coupling integer variables with continuous variables which are introduced to the objective function by Lagrangian multipliers. The Lagrangian relaxed problem can be decomposed into two sub-problems by separating continuous variables from integer ones. The sub-problem that relates to continuous variables is a linear programming problem which can be solved using standard software package OSL, while the other sub-problem is an integer programming problem which can be solved optimally by further decomposition. The subgradient optimization method is used to update Lagrangian multipliers. A production order scheduling simulation system for Baosteel is developed by embedding the above Lagrangian heuristics. Computational results for problems with up to 100 orders show that the proposed Lagrangian relaxation method is stable and can find good solutions within a reasonable time.