加热炉炉顶用可塑料施工技术及注意事项

可塑料是具有施工方便、使用寿命长等优点的新型耐火材料.如果加热炉炉顶管道布置较多,用可塑料代替浇注料施工炉顶是不错的选择,但必须遵照科学的施工技术,才能延长炉顶使用寿命.笔者总结出一些施工技术要求和注意事项,对炉顶可塑料捣打施工、支模方法、时间控制、锚固砖安装、合门技术及拆模后修整等方面有一定参考价值.     

喷涂修补法在可塑料耐材维护中的应用

针对邯钢公司2 250热轧加热炉可塑料使用和维护中遇到的问题,介绍了喷涂修补可塑料的施工步骤及注意事项。实践证明,该方法既能克服可塑料修补中新老耐材结合面难于处理的弊端,又能保证可塑料的施工质量;既适用于小局部修补又可用于大面积更换,特别适用于易受空间所限影响正常捣打部位。     

耐火可塑料简介

我单位在宝钢承建的初轧厂均热炉及无缝钢管厂的环形加热炉、再加热炉、淬火炉、回火炉上都有大量的引进耐火可塑料要进行施工。由于耐火可塑料在我国研制、生产和使用较晚,许多人对它尚不太熟悉,为了使大家对这种筑炉新材料、新工艺有所了解,现将耐火可塑料及其施工特点作一简要介绍。     

轧钢加热炉用耐火可塑料大型予制块的性能及其使用特征

一、引言近年来,为适应轧钢加热炉提高产量,延长使用寿命,国内外已逐渐采用耐火可塑料现场捣打施工。但由于现场捣打施工存在施工场地狭、周期长,需要较熟练的施工队伍等缺点,在国内轧钢加热炉上推广耐火可塑料,带来一定困难。试制了轧钢加热炉用耐火可塑料大型予制块,并在天津一轧厂经过两年多的试用、取得了明显的经济效果。二、耐火可塑料大型予制块的性能     

耐火可塑料在莱钢中型工程加热炉中的应用

耐火可塑料具有耐火度高，耐急冷急热性好，绝热性能好，抗渣性好，抗震性能及耐磨性能强等优点。文章总结了莱钢中型型钢工程中加热炉的炉墙、炉顶、烧嘴采用耐火可塑料的施工要点，遇到的质量问题及处理措施等。     

耐火可塑料在轧钢加热炉的应用

介绍了耐火可塑料在轧钢加热炉上的使用效果,并得出通过选择耐火可塑料作为炉衬,精心组织施工,科学烘炉可以延长加热炉炉顶及炉墙的使用寿命,同时能够提高产量和降低能耗.     

简述耐火纤维可塑料的施工

通过与其他耐火纤维炉衬进行对比 ,介绍了耐火纤维可塑料的材料性能及施工特点     

轧钢加热炉可塑料喷涂施工技术的探讨

本文着重介绍国外可塑料喷涂施工原理、方法、技术特点、技术设备规格、流程，以及它在生产中的实际操作及注意事项。     

可塑料喷涂施工技术及其应用

介绍国外喷涂可塑料的发展概况和趋势、国内对可塑料施工技术的研究和进展状况，以及它在宝钢高线加热炉上的应用情况。     

加热炉可塑料包扎及风扇式磨煤机的使用

一、加热炉可塑料包扎去年四月省局在锡钢召开节油(煤)会议后,我厂三个轧钢车间的三座加热炉利用大中修机会,全部采用了可塑料包扎炉筋管新技术。由于可塑料和不锈钢丝来源困难,我们首先在线材车间加热炉(风扇磨煤机配套)高温带采用可塑料包扎炉筋管,同时腰炉炉底和炉门盖绝热层也采用可塑料(可塑料是上钢一厂支援由上海冶金安装大队施工)。加热炉是单排侧出料连续加热炉,有     

新型塑料模具钢4Cr2Mn2NiMoV的研制

新研制的塑料模具钢为 4Cr2Mn2NiMoV ,经金相分析和力学性能检验及厂家使用表明 ,其特点是淬透性及抛光性能良好 ,预硬处理后经机械加工即可直接使用 ,是一种值得推广的新钢种。     

The effect of constraint-induced normal stress on the failure of notched TiAl components

Titanium aluminides are candidates for replacing nickel superalloys in some aircraft engine components. In uniaxial tension tests, these materials experience plastic strains at failure that place them in-between traditional definitions for ductile and brittle materials. This study considers the appropriate continuum mechanics failure criterion for these materials under multiaxial loading conditions (based on either the maximum equivalent plastic strain or the maximum normal stress). The material tested is a Ti-47.0Al-2.0Cr-1.9Nb alloy having a predominantly lamellar γ/α ₂ microstructure. Cylindrical notched tensile specimens that experience elevated normal stresses in their interiors due to circumferential constraint during plastic deformation have been investigated. Results are presented that quantify reductions in failure loads due to elevated normal stress, compared to those predicted by finite element models using a maximum equivalent plastic strain criterion. To properly interpret the experimental results, the effects of notch strengthening must be included in the model predictions. Model and experimental results suggest that this TiAl alloy has some sensitivity to normal stress and that a combined failure criterion is needed to accurately predict failure under multiaxial loading conditions. A fracture initiation and failure mechanism requiring a combination of normal stress and plastic straining is suggested that is consistent with observed features at fracture initiation sites.     

模具产业蕴藏巨大商机 未来高新科技掘金蓝海

模具在机械制造加工中占有非常重要的地位。模具生产技术也是衡量一个国家制造工艺水平的重要标志之一。随着塑料制品用量的越来越多,越来越广,塑料模具的比例就需要不断提高。因此,模具工业发展的趋势是非常明显的即：模具企业产品发展将大型化、精密化、多功能复合化。着重阐述了模具产品发展数字化、信息化,研究了发展适应高压成形工艺的气体辅助注射模具,同时指出了开发快速经济模具引起人们的重视。     

Near-Neutral pH Stress Corrosion Cracking Susceptibility of Plastically Prestrained X70 Steel Weldment

The application of strain-based design for pipelines requires comprehensive understanding of the postyield mechanical behavior of materials. In this article, the impact of plastic prestrain on near-neutral pH stress corrosion cracking (SCC) susceptibility of welded X70 steel was investigated with a slow strain rate tensile (SSRT) test. Generally, plastic prestrain reduces the SCC resistance in various welded zones. The SCC susceptibility of the test materials can be put in the following order: heat-affected zone (HAZ) > weld metal (WM) > base metal (BM). Fractographic analysis indicates that there are two cracking modes, mode I and mode II, during SSRT tests. Mode I cracks propagate along the direction perpendicular to the maximum tensile stress, and mode II cracks lie in planes roughly parallel to the plane where the maximum shear exists. The SCC of the BM is governed by mode I cracking and fracture of the HAZ, and the WM is dominated by mode II cracking. Damage analysis shows that the detrimental impact of plastic prestrain on the residual SCC resistance cannot be evaluated with the linear superposition model. A plastic prestrain sensitivity, a material constant independent of plastic prestrain, is proposed to characterize the susceptibility of SCC resistance to plastic prestrain, and it increases with the SCC susceptibility of the steels. The enhanced SCC susceptibility caused by plastic prestrain may be related to an increase in yield strength. The correlation of the ratio of the reduction in area in NS4 solution to that in air (RA _SCC/RA _air) with the yield strength is microstructure dependent.     

A complex mathematical model of processes of plastic flow of compressible materials

Conclusions A complex mathematical model of plastic flow of compressible materials is described. The model is versatile and, in the authors' opinion, free from many of the drawbacks of earlier models [9–11]. In particular, it can readily be adapted to analysis of virtually any process of plastic working under conditions of axisymmetric deformation; it enables all mechanical and temperature boundary conditions to be exactly fulfilled in all parts of the boundary S of a plastic flow region; it can be used for studying nonsteady-state processes of plastic working of metals with seats of deformation of complex shape (e.g., axisymmetric forging); it makes it possible to introduce starting data and extract resultant information in a form convenient to the user (production engineer).Translated from Poroshkovaya Metallurgiya, No. 5(281), pp. 18–24, May, 1986.     

高碳硅镇静钢中失效夹杂物检测方法的探讨

摘要：采用刚塑性有限元法解析了宽厚板立轧过程中头、尾凹形和边部狗骨的形成规律。轧件长度中心区域立轧时主变形区前、后外端约束始终存在，该区金属进入主变形区前后均没有协调运动，形成的狗骨较高，长度较小。轧件头部区域立轧时主变形区后外端约束始终存在而前外端约束逐渐形成，主变形区内金属易于沿轧件宽度和长度方向流动，轧件头部区域金属离开主变形区后的协调运动导致其头部宽度不足和头部凹形增大。轧件尾部区域立轧时主变形区前外端约束始终存在而后外端约束逐渐消失，主变形区内金属易于沿轧件宽度和长度方向流动，尾部区域金属在进入主变形区之前的协调运动增大了轧件尾部凹形。研究成果可用于指导热轧宽厚板立轧头尾短行程控制轧制和开发新的宽厚板平面形状控制技术。     

Variation of the yield stress of a porous metal during cold deformation

Conclusions An examination is made of individual factors involved in the variation of the yield stress of a porous material during deformation, and a method is proposed for determining them using empirical relationships between the mechanical properties and density of porous materials and information concerning the true variation of the yield stress of the relevant nonporous metal. The method proposed, which allows for the variation of density during deformation and gives values of yield stress which are in good agreement with experimental results, may be recommended for the determination of deformation forces in various production processes for the plastic working of porous materials.Translated from Poroshkovaya Metallurgiya, No. 1(193), pp. 7–13, January, 1979.     

Predicting the Behavior of an Earth and Rockfill Dam under Construction

This paper presents an application of a coupled hydromechanical formulation for compacted and rockfill materials to simulate the construction and impoundment of a zoned earth dam. The constitutive relation used to model the mechanical behavior of the shoulder, filter and core materials is the Barcelona Basic Model for unsaturated materials. The hydraulic behavior of dam materials requires the specification of their water retention characteristics and their permeabilities, which will be expressed as a function of porosity and degree of saturation. The model was used in the design stage of Lechago’s dam (Teruel, Spain), currently under construction. Soil parameters were obtained by laboratory tests performed on materials to be used in the dam. The step-by-step construction (following the sequence construction of nine horizontal layers, besides the downstream preloading layers) and subsequent impounding of the reservoir was simulated in a prediction exercise, which will be hopefully confronted with actual construction measurements in the near future. A parametric study was also performed to evaluate the effects of the compaction water content of the core material on the behavior of the dam.     

Deformation mechanisms in superplastic AA5083 materials

The plastic deformation of seven 5083 commercial aluminum materials, produced from five different alloy heats, are evaluated under conditions of interest for superplastic and quick-plastic forming. Two mechanisms are shown to govern plastic deformation in AA5083 over the strain rates, strains, and temperatures of interest for these forming technologies: grain-boundary-sliding (GBS) creep and solutedrag (SD) creep. Quantitative analysis of stress transients following rate changes clearly differentiates between GBS and SD creep and offers conclusive proof that SD creep dominates deformation at fast strain rates and low temperature. Furthermore, stress transients following strain-rate changes under SD creep are observed to decay exponentially with strain. A new graphical construction is proposed for the analysis and prediction of creep transients. This construction predicts the relative size of creep transients under SD creep from the relative size of changes in an applied strain rate or stress. This construction reveals the relative size of creep transients under SD creep to be independent of temperature; temperature dependence resides in the “steady-state” creep behavior to which transients are related.