Effect of Carbon on Grain Boundary Segregation of Phosphorus and Phosphorus-Induced Intergranular Fracture in High Purity Iron with Phosphorus

Ａｓｗｅｌｌｋｎｏｗｎ ,ｔｈｅａｄｄｉｔｉｏｎｏｆｃａｒｂｏｎｃａｎｐｒｅ ｖｅｎｔｔｈｅｐｈｏｓｐｈｏｒｕｓ ｉｎｄｕｃｅｄｉｎｔｅｒｇｒａｎｕｌａｒｆａｉｌｕｒｅｉｎｉｒｏｎ .ＢｕｔｉｔｉｓｔｈｅｒｅｓｕｌｔｏｆｕｓｉｎｇＡＥＳ (Ａｕｇｅｒｅｌｅｃ ｔｒｏｎｓｐｅｃｔｒｏｓｃｏｐｙ)ａｎａｌｙｓｉｓｉｎｆｒａｃｔｕｒｅｄｓｕｒｆａｃｅａｎａｌ ｙｓｉｓ .ＥｒｈａｒｔＨｅｔａｌ[1] ,ｉｎｏｒｄｅｒｔｏｅｘｐｌａｉｎｔｈｅｍｅｃｈ ａｎｉｓｍｏｆｃａｒｂｏｎｓｕｐｐｒｅｓｓｉｎｇｔｈｅｉｎｔｅｒｇｒａ…     

Nonequilibrium Grain Boundary Segregation of Sulfur and Its Effect on Intergranular Corrosion for 304 Stainless Steel

 The data obtained by bending tests for intergranular embrittlement after 45 h and 450 h exposure to Strauss solution have been reported for 304 stainless steel. The results show that an embrittlement peak appears at 650 ℃ for all samples quenched from 1260 ℃ and then sensitized for 150 h at 480, 565, 650, 730, 815 and 900 ℃ respectively. The temperature corresponding to the embrittlement peak is decreased to 565 ℃ when the sensitizing time is prolonged to 1500 h. In this paper, these data are analyzed with an isothermal kinetic model of nonequilibrium grain boundary segregation, indicating that the embrittlement peak is related to the critical time for nonequilibrium grain boundary segregation of sulfur.     

三氧化二锑中铁的测定

提出了一个快速测定三氧化二锑中铁的方法,邻菲啰啉光度法。λ＝ ５１０ ｎ ｍ ,用此法测定样品中 Ｆｅ , Ｒ Ｓ Ｄ（ｎ ＝ ７） 为４ ．７ ％ 。加标回收率为９６ ％ ～１０２ ％ 。     

Investigation on the Effect of Sulfur and Titanium on the Microstructure of Lamellar Graphite Iron

The goal of this work was to identify the inclusions in lamellar graphite cast iron in an effort to explain the nucleation of the phases of interest. Four samples of approximately the same carbon equivalent but different levels of sulfur and titanium were studied. The Ti/S ratios were from 0.15 to 29.2 and the Mn/S ratios from 4.2 to 48.3. Light and electron microscopy were used to examine the unetched, color-etched, and deep-etched samples. It was confirmed that in irons with high sulfur content (0.12 wt pct) nucleation of type-A and type-D graphite occurs on Mn sulfides that have a core of complex Al, Ca, Mg oxide. An increased titanium level of 0.35 pct produced superfine interdendritic graphite (~10 μm) at low (0.012 wt pct) as well as at high-S contents. Ti also caused increased segregation in the microstructure of the analyzed irons and larger eutectic grains (cells). TiC did not appear to be a nucleation site for the primary austenite as it was found mostly at the periphery of the secondary arms of the austenite, in the last region to solidify. The effect of titanium in refining the graphite and increasing the austenite fraction can be explained through the widening of the liquidus-eutectic temperature interval (more time for austenite growth) and the decrease in the growth rate of the graphite because of Ti absorption on the graphite. The fact that Ti addition produced larger eutectic cells supports the theory that Ti is not producing finer graphite because of a change in the nucleation potential, but because of lower growth rate of the graphite in between the dendrite arms of a larger fraction of austenite. In the presence of high-Ti and S, (MnTi)S star-like and rib-like inclusions precipitate and act as nuclei for the austenite.     

模拟文物铸铁的阴极保护

在模拟的文物铸铁上,研究已生成较厚锈层的带锈铸铁在3.5%NaCl溶液中阴极保护的可能性和可行性,并确定最佳保护参数。结果表明,带锈铸铁的阴极保护是可行的;在本体系中最佳保护电位范围是-900~-1000mV(SCE);当保护电位比-1100mV(SCE)更负时,保护效率将显著降低。     

低合金钢残余元素Cu-As-Sn的晶界偏析对晶间脆性断裂的影响

用Gleeble-1500热模拟机、扫描电镜和俄歇能谱仪研究了0.10Cu-0.07As-0.05Sn对低合金钢(%:0.15C、0.36Si、1.40Mn、0.003S、0.019P)高温延塑性的影响,凝固过程中的偏析和热处理过程的晶界偏析。结果表明,Cu-As-Sn在晶界的偏析明显加剧第Ⅲ脆性凹槽区的深度和宽度,提高该区上限临界温度;连铸坯不存在明显的Cu-As-Sn晶界偏析,850℃拉伸至屈服的试样和热轧板试样存在明显的Cu-As-Sn晶界偏析,说明热变形加剧残余元素的晶界偏析。     

Effect of Ball Burnishing Treatment on the Fatigue Behavior of 316L Stainless Steel Operating Under Anodic and Cathodic Polarization Potentials

Corrosion fatigue (CF) behavior of AISI 316L was investigated in a 3 pct NaCl aqueous solution at an R = ? 1 stress ratio and a frequency of 60?Hz at room temperature. The test scale specimen was 7 cm². The passive (0 mV_Ref), pitting (120?mV_Ref), and cathodic (? 1400?mV_Ref) polarization potentials were statically applied and recorded during CF tests until the samples were broken. The shaft material surface was treated with a ball burnishing (BB) process. By the results, the fatigue behavior of AISI 316L was affected by polarization potential and surface treatment. Under 0?mV potential charged tests for 5?×?10⁵ cycles, BB treatment raised the CF strength of the shaft material from about 448 to 702?MPa with a percent 57 increase. Fractographic observations revealed that corrosion pits occurred during the experiments where anodic potential was applied and that transgranular surface fractures occurred in all cases.     

Effect of Sulfur Content and Sulfide Shape on Fracture Ductility in Case Hardening Steel

 The effects of sulfur content and calcium addition on smooth axisymmetric tensile fracture ductility of case hardening steel DIN 18CrNiMo7-6 have been investigated. The quantitative metallographic analysis of sulfide inclusions and the correlations between sulfide inclusions and fracture ductility were examined. Sulfide inclusions were found to have deleterious effect on fracture ductility, whereas the effect can be offset to some extent by calcium-treatment due to less easily deforming of sulfides during hot-working. The product (AA·λAW) of sulfide inclusion area fraction (AA) and its area-weighted aspect ratio (λAW) can be used as a parameter to describe the effect of sulfide inclusions on fracture true strain.     

矿浆电解溶液中锑铁分离研究

研究了矿浆电解溶液"氯化钠+盐酸体系"中铁屑对锑的置换反应。在反应时间1h、铁屑加入量1.2倍、搅拌速度230~400r/min、温度20~50℃时,锑置换率可以达到99.5%以上,得到的海绵锑纯度达98%以上,解决了矿浆电解过程中铁的积累问题。     

Synthesis and Characterization of Iron Disulfide for Cathodic Material

Currently there is a growing technological demand for electrochemical systems of high energy density drainage combined with reliability. Among these systems, the thermal batteries and batteries for vehicles with iron disulfide cathodes are promising technological options. Standard iron disulfide can be obtained by purifying natural pyrite; however, the synthesis of a pure iron disulfide brings some challenge because the main target is to obtain this compound as powders with some characteristics that can assure its application in those high-technological systems. This work aims to characterize an iron disulfide (FeS₂) synthesized by a gas?Csolid reaction between sulfur and hematite and, also, to appreciate briefly the availability of the method and to evaluate some of the obtained material properties. Among the techniques used for characterization include X-ray diffraction associated with Rietvelt method, scanning electron microscopy equipped with X-ray energy dispersive, chemical elementary analysis (ICP-OES), thermal analysis, and gas pycnometry. The results indicated that the applied method has produced an iron disulfide with interesting properties for electrochemical applications, and complete conversion was reached for the experiments conducted at 773?K (500?°C) for 30?minutes.     

Effect of Sulfur Contents on Fracture Toughness of Wheel Steels for High Speed Train

The effect of different contents of S on fracture toughness of railway wheel steels for high speed train has been researched.The results show that there are kinds of non-metallic inclusion when O content retaining at about 10×10-6,such as Al 2 O 3 inclusions and Al 2 O 3 +MnS complex inclusions and single MnS inclusions.This is connected with S content level in steel.Fracture toughness of railway steel increase obviously because of Al 2 O 3 covered by MnS around when S content is increase to about 70×10-6.It shows that,after Al 2 O 3 covering by MnS around,stresses around complex inclusion decrease rapidly till disappear when analyzed by tessellated stresses theory.That is the reason of fracture toughness rise.     

云南文山某铁精矿脱硫的试验研究

随着铁矿资源的进一步开发，如何脱除高硫铁精矿中的硫、提高铁精矿质量越来越受到人们的重视。以往铁精矿脱硫普遍使用大量硫酸和硫酸铜进行活化，硫酸用量大不但在生产过程中严重腐蚀设备，而且对工作环境影响很大，特别是多金属矿石的选别，浮选过程往往加入大量的石灰，将对摇床的结垢的变形产生严重的影响。本文从磁铁矿和磁黄铁矿的分选流程和药剂制度两个方面分析了铁精矿脱硫的方法，并对云南文山某磁铁精矿进行浮选脱硫试验研究发现：用Na2S＋CuSO4活化脱硫比硫酸和硫酸铜活化脱硫效果好，硫的脱除率提高％。     

The Effect of Sulfur Concentration in Liquid Iron on Mineral Layer Formation During Coke Dissolution

The effects of sulfur concentration in liquid iron on mineral layer development between coke and iron as coke dissolves in a 2 mass pct carbon-iron liquid have been investigated at 1773 K (1500 °C). The initial sulfur in iron concentrations used ranged from 0.006 to 0.049 mass pct. Key findings include that the two-stage dissolution behavior exhibited in the carbon transfer from coke to iron, as reported in a previous study by the authors, at low initial sulfur in iron contents, was also apparent at the higher values used in this study. This two-stage behavior was attributed to a change in the mineral layer density as a result of changes in mineral morphology at the interface. In addition to confirming the two-stage behavior of the carbon-transfer kinetics at the higher sulfur concentration in iron levels, after a period of time, a solid calcium sulfide layer formed on the mineral layer. The sulfide layer formed after approximately 40 minutes, and the proportion of sulfide in the mineral layer increased with increased experimental time and initial sulfur concentration in iron. It was usually found at the iron side of the mineral layer and was associated with calcium-enriched calcium aluminates. Thermodynamic analysis of this layer confirmed that the sulfide is stabilized as the mineral layer is enriched by calcium.     

某尾矿综合回收硫、铁资源试验研究

文章介绍了某尾矿的工艺矿物学性质,根据尾矿的矿石性质,确定采用硫浮选→磨矿→磁选工艺流程,获得了全铁63．44％、含硫0．54％的铁精矿;硫35．58％的硫精矿。     

Theoretical Estimation of Temperature-Dependent Surface Tension of Liquid Antimony,Boron, and Sulfur

A theoretical calculation of the temperature-dependent surface tension of liquid antimony, boron, and sulfur in the temperature ranges 904 K to 1200 K (631 °C to 927 °C), 2349 K to 3085 K (2076 °C to 2812 °C) and 388 K to 453 K (115 °C to 180 °C), respectively, in the framework of Eyring theoretical consideration is explored. A reasonable agreement between the calculated and measured reported values is detected. The surface tensions of the three elements decrease linearly with temperature, with a change of 5.7 pct, 15 pct, and 16 pct, and the calculated surface tension data are expressed as γ = 388–0.0749 (T-Tm), γ = 1200–0.259 (T-Tm), and γ = 71–0.183 (T-Tm) (mJ/m²) for Sb, B, and S, respectively. Moreover, the surface tension was calculated, at melting point, for liquid metalloids and liquid nonmetals.     

深化内涵挖潜 实现特钢厂铁水调运

分析了特钢厂铁路铁水调运的现状和困难,绘制了机车运行图,制定了切实可行的运输方案,保证了特钢厂铁水的生产需求。     

锑冶炼中砷碱渣与二氧化硫烟气综合回收清洁工艺探讨

通过将炼锑中产生的含砷碱渣经过浸出、含砷碱溶液吸收废气二氧化硫、硫化钠等硫化剂脱砷、硫酸铁深度除砷以及净化浓缩干燥等过程后,难以处理的砷碱渣和废气低含量的二氧化硫得到彻底处理。整个处理过程,锑回收率达到99%,砷开路率超过90%,二氧化硫经吸收超过95%,使气体达到排放标准,碱转化为亚硫酸钠,达到了以废治废的目的,是一种清洁炼锑的工艺。     

高砷锑粗铜电解沉积物的表面质量控制

分析了高砷锑粗铜在电解精炼时阴极沉积物的几种常见表面缺陷产生的原因,提出了改善表面质量的有效措施。通过在生产过程中应用,取得了很好的效果。