Bridge foundations contribute significantly to the serviceability and efficiency of in-service transportation networks. Foundation failure may lead to catastrophic failure of the entire structure, which in turn results in system failure, loss of life, and detours. When the soil within ground surface layers fails to satisfy the bearing capacity requirements, deep foundations such as tubular-steel concrete-filled piles are commonly used in practice. A challenge that often exists with these systems is the uncertainty surrounding in-service capacity as well as condition, which is difficult to determine from the surface. As a consequence, transportation agencies such as the Wisconsin Department of Transportation use conservative approaches, such as neglecting the tubular-steel contribution or bounding the compressive strength of the core concrete, to design these systems. This approach, while effective for safety, can yield overly conservative and costly designs. The main purpose of this investigation was to evaluate the behavior of tubular-steel, concrete-filled, cast-in-place pilings, with a concentration on the compressive strength and composite behavior between concrete core and steel shell. In this regard, a series of experimental studies, including composite and noncomposite compression loading, core samples, push-through, and flexural testing together with a compatible finite element analysis, were conducted on a series of field-cast piles with different geometrical properties. The results indicated that the steel shell made a significant contribution to the axial loading capacity of the cast-in-place piles. Moreover, no evidence of bond loss was observed during the corresponding experimental studies.

关键词：管状钢铸；钢铁；打桩

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Austenitization is a solid-phase transformation process accompanied by nucleation and nucleus growth controlled by long-range carbon diffusion. In our work, a method was developed for constructing spheroidite model structures in such a way that their different parameters (the size of ferrite grains, the average value of carbon concentration, the size of cementite spheroids) could be changed optionally. In addition, a nucleation model of free energy base was created by which the difference between the two different places of nucleation can be distinguished on the basis of their free energy. The effects of structure parameters, interface free energies and temperature on the nucleation rate of austenite were investigated by cellular automaton simulations.

关键词：奥氏体化；成核速率；球状渗碳体；元胞自动机

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Illinois, like many other large states, has several microclimates where temperature and rainfall can vary. These variations can affect the corrosion rates of sign and signal structures, light poles, and other highway structures. Each atmospheric zone, whether they are rural, semirural, suburban, industrial, or marine areas, may be subjected to salt fall or salt spray, which can affect metals or coatings after prolonged exposure. These highway structures are typically fabricated from weathering steel, galvanized steel, painted steel, or aluminum. Each of these metals and their coatings bear a fabrication cost and have distinct ranges of durability in different atmospheres. Rural and semi-rural atmospheres cause the least corrosion damage to metal and coated surfaces. Suburban environments generally have moderate effects, compared to industrial and saline areas, which have the most corrosive atmospheres. Weathering steels have greater durability in moderate and many industrial atmospheres compared to carbon steels, such as ASTM A36 or SAE 1020. The cost differences between ASTM A36 and ASTM A588 vs. the ASTM A710 Grade 50 steel described in this report are small. Based on data obtained from WorldSteelPrices.com, as of July 2013, the price of ASTM A36 was about $0.295 per lb compared to $0.340 per lb for ASTM A588. Because A710 has slightly higher nickel and copper contents than A588, its cost is estimated to be about $0.36 per lb, based on a metric tonne.

关键词：涂料；耐腐蚀；损害；钢铁

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Iron is produced by the reduction of iron ore and other iron oxides as a precursor to steel and by remelting of metallic stock to produce a family of iron-based alloys (cast irons) for industrial use. More than 1 billion metric tons of iron is produced annually by reduction processes.1 Blast furnaces account for more than 90% of iron reduction with the rest accomplished through direct reduction or "alternate ironmaking" processes. Cupola furnaces, rotary furnaces, and induction furnaces are the primary units for cast iron re-melting. In 2009, the cast iron production of the main industrialized countries was 58.6 million metric tons. The role of oxygen combustion in reduction processes is described in Sections 21.2 and 21.3, and in re-melting processes in Section 21.4.

关键词：铁矿石；氧化铁；钢铁

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Metal framing and glass is a broad category of exterior enclosure systems that includes storefront, window wall, and curtain wall systems. The metal framing components are primarily aluminum, but also include stainless steel, bronze, or other architectural quality metals. Infill supported by or within the framing includes transparent or opaque materials. Transparent infill materials include insulating, laminated, or monolithic glass; polycarbonates; and thermoplastics. Opaque infill materials include architectural metals such as aluminum, stainless steel, or bronze; natural stone; fiber reinforced panels; terra cotta; or louvers.

关键词：金属框架；不透明填充材料；钢铁

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Based on the shape detecting principle and the digital signal technology,a new shape meter was developed thorough theoretical analysis and industrial adjustment to develop the shape detecting roll,the shape signal processing method,the original signal compensation mechanism and so on.The shape meter has good performance and stability,which can effectively avoid the scratchof steel strip surface,accurately detect real online strip shape and provide accurate online shape datum for shape control system.It was applied in 1250 mm cold rolling mill,the actual industrial tests prove that the shape signal was stable and reliable,met the harsh condition and the online technical requirements,and could improve shape quality significantly.

关键词：板形仪；形状检测；形状控制；冷轧带钢

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The world shipbuilding industry since the beginning of the last century with flux cored wire material.Since the flux cored wire material use welding materials has developed into a more efficient submerged arc welding consumables and gas shielded welding welding consumables and can be more easily combined with automated welding and robot welding.So far,flux cored material applications favored.Gas shielded arc welding consumables mainly divided solid wire and flux cored wire,flux cored wire applications has increased year by year because of its practicality and efficiency.Flux cored wire as the main welding consumables trends,especially in the thick carbon steel plate welded favored.In order to understand the nature of the thick-walled components weld cracking and produces original Due on a thick-wailed T-joints butt weld ultrasonic flaw found Two crack metallographic and SEM fracture analysis.

关键词：药芯焊丝材料；气体保护；焊接裂纹

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Accurate estimates of bearing stiffnesses are often necessary for bridge design and construction calculations. In the case of steel-reinforced elastomeric bearing pads, the compression stiffness or roll stiffness is sometimes difficult to estimate because of complex deformations of the elastomer. A method of numerical analysis for estimating the axial and roll stiffnesses of bearing pads is presented. To validate the axial calculation method, experimental compression tests were performed on pad specimens constructed in accordance with Florida design standards. A method for calculating roll stiffness is also presented in which the pad is modeled as a grillage of compression-only axial springs. The grillage method was partially derived from roll stiffness data measured in a separate experimental study. The grillage method was demonstrated to accurately capture both the nonlinear moment-rotation behavior caused by liftoff of the girder from the pad and the observed sensitivity of roll stiffness to initial compressive loading caused by self-weight of the girder. Reductions in roll stiffness that are caused by girder slope relative to the pad were also examined.

关键词：轴承刚度；精确估计；钢铁

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Fine balance between active galvanic and passive barrier corrosion protection by zinc-rich hybrid paints is explored depending on the absolute and relative amounts of the electrically semi-conducting particles, viz. polypyrrole (PPy) modified alumina hydrate and multi-walled carbon nanotubes (MWCNTs) and the zinc pigments. The former was varied between 3.21 and 1.75 wt.%, the latter was altered from 70 to 80 wt.% in the primers. The coating with less zinc indicated firm and stable barrier nature in a 254 h immersion test whereas the primer with greater zinc content afforded superior galvanic corrosion prevention in salt-mist test over 142 days. Different nature of the coatings are expounded on the basis of structure and 3D arrangement of the nano-size inhibitor particles in the epoxy vehicle besides interpreted considering varied grain contents caused changing electrical percolation and electrolytic conductivity of the primers.

关键词：聚吡咯修饰碳纳米管；低碳钢；富锌涂料混合

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The influence of yttrium on the corrosion resistance of four valve steels (X33CrNiMn23-8, X50CrMnNiNbN21-9, X53CrMnNiN20-8 and X55CrMnNiN20-8) in combustion gases of fuel oil containing 10 wt. % of biocomponents has been studied at 1173K under thermal shock conditions. These experiments have been carried out by rapid heating of the studied materials up to 1173K and after two hours cooling down to room temperature. These thermal shocks have been repeated hundreds of times, determining after every shock the mass changes of the corroded samples. It has been found that small amount of yttrium deposited on the steel surface using electrochemical treatment considerably improves the scale adherence and consequently corrosion resistance in the case of X33CrNiMn23-8 steel, containing the highest chromium concentration.

关键词：阀门钢；腐蚀；燃烧气体；;热冲击；钇效果

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