X55SiCrA连铸坯的原位分析研究

文章应用原位分析系统OPA-300,形成X55SiCrA弹簧钢150方连铸坯纵截面整体的原位分析数据。分析表明,C、Mn、S、Cr元素在连铸方坯纵截面中心存在正偏析,C、P元素点状正偏析较为严重,Mn、S、Cr元素方坯边缘存在负偏析;Si、P元素在150方连铸坯纵截面成分分布比较均匀,中央与边缘成分分布差异不明显。C、Si、Mn、Cr元素统计偏析度均小于0.055,P、S元素统计偏析度分别为0.317、0.22,通过优化连铸系统参数,可对连铸坯的元素C偏析等进行改善。     

材质元素对不锈钢杯重金属析出量的影响

采用火花直读光谱仪分析了110批次不锈钢杯中C、S、Si、Mn、P、Cr、Ni7种材质元素的含量,同时采用石墨炉原子吸收分光光度法分析了它们的Pb、Cr、Ni、Cd、As5种重金属元素的析出量.研究了不锈钢材质对重金属元素析出量的影响.结果表明,材质元素Ni含量对重金属元素Pb的析出量有显著影响,材质元素C、Si、Mn、P含量对重金属元素Cr的析出量有显著影响,材质元素C、S、Mn、Cr、Ni含量对重金属元素Ni的析出量有显著影响,材质元素Si、Mn、P、Cr、Ni含量对重金属元素As的析出量有显著影响.     

X射线荧光光谱法在中、低合金钢类钢筋建材检测中的应用

用高性能飞利浦PW2424型X射线荧光光谱仪,测定中、低合金钢类钢筋建材中的Si、Mn、P、S、Ni、Cr、Cu、Ti、V、Nb、Mo等11个化学元素的含量。创建标准工作曲线,给出各元素的干扰校正系数和基体效应校正系数。方法准确、灵敏,稳定性好,速度快。     

辉光放电质谱仪测定不锈钢中微量元素的不确定度分析

本文以不锈钢中铁(Fe)元素作为内标,采用辉光放电质谱仪测定不锈钢中锰(Mn),硅(Si),硫(S),磷(P),镍(Ni),铬(Cr),钨(W),钒(V),钼(Mo),铝(Al),钛(Ti),铜(Cu)等12种元素。讨论了测试过程中由测量重复性、样品不均匀性和标准样品本身不确定度等因素所带来的不确定度分量,计算出测定不锈钢中的12种元素百分含量的合成不确定度及扩展不确定度。研究结果表明,采用辉光放电质谱仪测定不锈钢中的12种元素含量的扩展不确定度均小于0.01%。     

光电直读法测定中低合金钢元素含量不确定度的分析

本文系统地分析了光电直读法测定中低合金钢元素含量不确定度的影响因素,对其影响程度进行了评定,并以本实验室Si、Mn、Ni、Cr、Cu等元素检测为例,对其不确定度做了详细分析,结果表明:在用光电直读光谱仪对元素含量分析过程中,标准物质与样品间基体含量的差异对测量结果的准确度影响最大,其次为标准曲线的线性因素影响及样品本身的物理性能及均匀程度的影响.     

快速凝固技术在材料科学中的应用(下)

(一)在铝合金中的应用大多数合金元素在铝中的溶解度都很低,因此普通铸锻法生产的铝合金的合金化仅限于极少数几个元素如Mn、Cu、Si、Zn等。快速凝固技术不仅明显增加这些元素的固溶度极限,而且扩大了过渡族金属如Fe、Cr、Ni、Co、Li在铝中的添加量。快速凝固粉末冶金技术使铝合金化学成份均匀;偏析极小;晶粒细化;弥散相均匀细小,从而使铝合金的强度、弹性模     

三维原子探针表征淬回火Cr-Mo-V-Ni中合金钢的元素分布

将Cr-Mo-V-Ni中合金钢在1 030℃奥氏体化保温0.5h后油淬,在600℃回火2次,每次2h。结合光学显微镜(OM)和扫描电子显微镜(SEM),采用三维原子探针(3DAP)技术分析了淬火态和回火态各元素原子的三维空间分布以及碳化物内部和碳化物/基体界面处元素分布和成分变化。结果表明,淬火试样中C原子由于自回火和短程扩散出现了较为明显的片状偏聚,而其他合金原子Cr、Mn、Mo、Si、V和Ni基本分布均匀;回火试样中C、Cr、Mo和V发生共偏聚形成厚度约10nm的合金碳化物M23C6,Si原子形成一层薄薄的偏聚层包裹着M23C6,而Ni又包裹着Si原子而偏聚于最外层。     

Cr20Mn10Ni4Si3N抗咬耐蚀不锈钢抗咬机理探讨

新研制的Cr20Mn10Ni4Si3N抗咬耐蚀不锈钢,除了具有Cr-Ni型不锈钢的特点外,还克服了Cr-Ni型不锈钢所不能解决的问题——咬死(粘着磨损)。本文探索了Cr20Mn10Ni4Si3N钢抗咬机理,与1Crl8Ni9Ti钢作比较,并探讨了此新钢种中Mn、Si含量与抗咬性能的关系。用X光电子能谱(ESCA)和俄歇电子能谱(AES)结合氩离子溅射刻蚀技术进行测定,证实此钢种表层有一层相当厚的氧化锰和硅酸盐表面膜,而一般18-8型Cr-Ni不锈钢则不具有这种膜。一定含量的Mn、Si在钢表面形成氧化物膜是此钢种具有良好抗咬性能的原因。     

PW4400荧光光谱仪在分析铁铝合金上的应用

铁铝合金是以铁、铝为主要成分，不含贵重元素的另一类高电磁性能的软磁合金，在微电机中得到应用。本文介绍了利用PW4400荧光光谱仪检测铁铝合金中Mn、Si、Ni、A1、Cr、Cu．元素的含量，分析结果可靠，能够满足生产需求。     

60mm厚Q420qE钢板探伤不合原因分析

利用金相显微镜、扫描电镜和电子探针波谱仪对探伤不合试样进行显微分析。结果表明：在钢板中心有肉眼可见的裂纹,裂纹附近有硫化物夹杂、氮化铌、氮化钛未溶相;引起探伤不合的主要原因是在板厚中心部位的有粗大的强贝氏体偏析条带,裂纹位于偏析条带上,强贝氏体偏析条带主要是P、s、Mn、Nb、Ti元素的偏析;且在裂纹附近观察到硫化物和氮化物夹杂。根据检测结果,对钢板生产工艺提出改进措施,避免同类质量问题在今后生产中在出现。     

Selective oxidation and segregation during annealing of steels at low oxygen partial pressures

Abstract

Industrial annealing of automotive steel grades is carried out in order to improve the mechanical properties and to adjust the grain size. However, the surface chemistry changes drastically due to selective oxidation and segregation phenomena, which significantly influence the further surface treatment, i.e. hot dip galvanizing.

The paper discusses results of laboratory experiments on selective oxidation and segregation of minor alloying elements Mn, Al, Cr and Si and non-metallic elements B, P and S during annealing of steel sheets in an N₂–5%H₂ atmosphere as a function of dew point. It will be shown that at lower dew points mostly external oxidation of Al and Mn occurs, where B shows a high tendency to segregate to the free surface and to form a BN film, especially observed on ferritic/austenitic steel. With increasing dew point, the oxidation of Al becomes internal and Mn, Si and Cr are oxidized externally. Boron also segregates to the surface by forming mixed Mn–B oxides and in the case of ferritic steels suppresses Si segregation and oxidation. The formation of phosphates by segregation of P becomes important at a D.P. of 0°C.     

Wear Resistance of Deposited Layer Using Nickel-Based Composite Powders by Plasma-Arc Surfacing

Nickel-based composite alloy powders were deposited on the surface of Q235 steel by plasma-arc surfacing in this work. Optimal proportions of elements intensifying the composite powders were ascertained by orthogonal design of three factors and three levels and orthogonal polynomial regression analysis , which Cr , Mn , W were 10% ,4% and 7 % respectively.Phase and structure of deposited materials were characterized by optical microscope and X- ray diffraction. Hardness tests and wear resistance tests were carried out to determine the performance of the deposited layers. The results show that the microstructure of deposited layers of composite powders mainly consist of γ-( Ni, Fe ) , γ- Ni, WC, W2 C, Mn31Si12, Cr23 C6,Cr7 C3, Cr, NiB, Ni2B etc. Wear resistance and hardness of the surface increased evidently.     

Limited impact endurance of 30CrMnSiNiN steel

The aim of this investigation was to study the effect of tempering temperature and metal purity on limited impact endurance under tensile loads at room and subzero temperatures. The tests were carried out on quench-hardened specimens of two grades of 30CrMnSiNiN steel: electric-arc smelted, i.e., in the initial condition (0.29% C, 1.3% Mn, 1.09% Si, 1.58% Ni, 1.04% Cr, 0.2% Cu, 0.012% S, 0.015% P, 0.01% O₂, 0.01% N₂) and subjected to a vacuum-arc refining (VAR) treatment (1.08% Mn, 0.007% S, 0.004% O₂, 0.003% N₂; the remaining impurities as in steel in the initial condition). VAR produces a substantial reduction in the content of O₂, N₂, S, and nonmetallic inclusions in the steel which, after this treatment, had a higher impact strength but virtually the same static strength properties.     

超低碳焊条钢的VOD冶炼

设计的初炼炉出钢成分(w,%)为:C0.70～0.90;Mn、Si0.20～0.30;Al0.010～0.020,出钢温度为1660～1680℃,为VOD精炼超低碳焊条钢提供了足够的热能。初炼炉热装50%铁水,采用氧化法冶炼能有效控制砷、铜、磷、铬、钒等微量元素的含量;VOD精炼过程中通过工艺手段获取"玻璃"渣是控制碳、氧、氮、铝、硅、锰等元素含量行之有效的方法。制定的EAF+VOD冶炼工艺保证了生产的焊条钢各项指标均满足技术要求,质量达到国际同类产品的水平。     

Lengthening kinetics of ferrite plates in high-strength low-carbon low alloy steel

The lengthening of ferrite plates in a high-strength low carbon low alloy steel, which contained 1.62 mass% Mn and small amounts of Si, Mo, Ni, Cr, and Nb, was observed in situ under high-temperature confocal laser scanning microscopy. Applying the analysis by Speich and Cohen to the growth of a lath-type plate, it was found that the measured lengthening rates are likely to fall between those calculated assuming para- and NPLE modes from the semiempirical equation proposed by Hillert, while they scattered widely presumably because the plate morphology was not a lenticular disk. In the temperature range of measurement, solute drag due to alloying element segregation at the boundary between plate tip and the matrix may not operate to an appreciable extent. The retardation of lengthening from that calculated under paraequilibrium could occur by intrinsic friction of α/γ boundary.     

Identification of nanoparticles of niobium carbide in steel 10Cr13Mn12Si2Ni2Cu2Nb

The austenitic chromomanganese steel 10Cr13Mn12Si2Ni2Cu2Nb (DI59) widely used in thermal power engineering is investigated by TEM, SEM, differential X-ray phase analysis, and energy dispersive X-ray spectroscopy. The combination of these methods makes it possible to find nanoparticles of the second phase of niobium carbide of the film form.     

脉冲真空弧源沉积类金刚石薄膜耐磨特性研究

本文利用脉冲真空弧源沉积技术在Cr17Ni14Cu4不锈钢和Si(100)基体上制备了类金刚石(DLC)薄膜,研究在不同基体偏压下,DLC薄膜的结构与性能.采用拉曼光谱和X射线光电子能谱(XPS)研究DLC薄膜的原子结合状态,利用CSEM销盘摩擦磨损试验机研究其耐磨性,利用HXD1000B显微硬度仪测试其显微硬度,并采用压痕法评价其结合力.研究结果表明:DLC薄膜与基体结合牢固.随着基体偏压的提高,DLC薄膜内sp3键含量增大,薄膜硬度提高.Cr17Ni14Cu4不锈钢表面沉积DLC薄膜后,耐磨性大幅度提高,本文探讨了DLC薄膜的耐磨机理.