智能分钢机的研制

通过研制智能分钢机可以解决钢铁企业钢材点支后按包装要求自动分开,实现包装过程全自动化操作,可以大大提高劳动生产率,并将工人从恶劣的工作环境中解放出来,智能分钢机应用于生产后经济效益和社会效益巨大,推广应用前景广阔。

引进钢坯分钢机介绍

目前国内轧钢车间使用的分钢机构大都存在一些缺点 ,现对引进分钢机进行简单介绍 ,特别是对引进分钢机的系统构造及工作原理进行分析 ,将国内分钢机或拨钢机与引进分钢机进行比较 ,找出制约现代轧钢厂生产节奏的原因 ,以便适应国内市场的需求变化 ,同时消除由于分钢机存在一些缺点而造成的设备事故及人身安全隐患。

推钢式分钢机的设计与研究

推钢式分钢机应用在冶金行业上,是连续性生产线上重要的机械设备。以设计实例情况为背景,对推钢式分钢机总体结构设计,非标件的设计研究,标准件的选型,重要零部件的强度校核,进行了详细阐述。结合设计实例,提出了分钢机设计、制造、安装及使用过程中应该注意的问题。设计的推钢式分钢机已经投产使用,运行状况良好,证明了设计的合理性。对同类设计产品的设计提供了一定的参考价值。

液压分钢及多定尺撞齐机的设计

1 概述最近几年,公司投入一定的资金对我厂的轧机列进行了两次较大的技术改造,使我厂的设备装备水平有了较大的改善,产量也从1993年的2万吨,猛增至1997年的6万吨。由于缺乏资金,精整区域的设备没有进行相应的配套改造。

Kinetics for static recrystallization after hot working of 0.38C-0.99Cr-0.16Mo steel

The restoration mechanisms for static recrystallization of work-hardened austenite were investigated by using double-pass compression tests performed on medium-carbon steel containing chromium and molybdenum. The softening fraction was defined by 2% offset method. The results show that Avrami exponent of about 0.21 is insensitive to deformation temperature, indicating that the action of steel grade should be considered. The time of 50% recrystallization (t0.5) decreases noteworthily with the increase of deformation temperature. Apparent activation energy for static recrystallization of 195 kJ/mol, which is close to that of vanadium microalloyed steel, is obtained by calculating. The increasing trend of the driving force for recrystallization is opposite to that of the deformation temperature, which is attributed to the number of operative slip system increasing as temperature increasing.

Scheduling optimization problem considering time-of-use tariffs and piece-rate machine maintenance in EAF steelmaking

An operating schedule of the parallel electric arc furnaces(EAFs)considering both productivity and energy related criteria is investigated.A mathematical model is established to minimize the total completion time and the total electricity cost.This problem is proved to be an NP-hard problem,and an effective solution algorithm,longest processing time-genetic(LPT-gene)algorithm,is proposed.The impacts of varied processing energy consumption and electricity price on the optimal schedules are analyzed.The integrated influence of the different weight values and the variation between the peak price and the trough price on the optimal solution is studied.Computational experiments illustrate that considering the energy consumption costs in production has little influence on makespan;the computational performance of the proposed longest processing time-genetic algorithm is better than the genetic algorithm(GA)in the issue to be studied;considerable reductions in the energy consumption costs can be achieved by avoiding producing during high-energy price periods and reducing the machining energy consumption difference.The results can be a guidance for managers to improve productivity and to save energy costs under the time-of-use tariffs.

Experimental observation and computer simulation on non-equilibrium grain-boundary segregation kinetics of phosphorus

An experimental study and computer simulation on non-equilibriumgrain-boundary segregation kinetics and the critical time for phosphorus in 12CrlMoV steel (which isused in steam pipeline of ships) are put forward in this paper. The segregation level ofphosphorus with solution temperature 1 050 ℃ at the isothermal holding temperature of 5401 , havebeen measured at grain-boundaries. A non-equilibrium grain-boundary segregation kinetics curve ofphosphorus is given. The critical time for phosphorus non-equilibrium grain-boundary segregation isabout 500h at 540 ℃ for the experimental steel. When the holding time is longer than 1 500 h ,non-equilibrium segregation disappears and the level of segregation reaches full equilibrium. Thesimulation using the kinetic equations of non-equilibrium grain-boundary segregation is in goodaccordance with the experimental observation for phosphorus in steel 12Crl MoV. The non-equilibriumgrain-boundary segregation kinetic model is therefore proved.

Finite element analysis on nut post structure of Three Gorges Project ship lift

A nonlinear finite element model of the nut post reinforced concrete （RC） structure of the safety mechanism in the Three Gorges Project （TGP） ship lift was built by ANSYS software. Some irregular structures such as the nut post and the rotary rod were divided by curved surface into a series of regular parts, and the structures were all meshed to hexahedron. Constraint equations were defined between two interfaces with different element sizes and mesh patterns. PRETS179 elements were used to simulate the preload in the tendons and the pre-stressed screws, and the loss of prestressing force was calculated. Five extreme load cases were analyzed. The stress of each part in the structure was obtained. The results indicate that the maximum compressive stress of concrete C35 is 24.13 MPa, so the concrete may be partially crushed; the maximum tensile stress of the grouting motar is 6.73 MPa, so the grouting motar may partially fracture; the maximum yon Mises stress of the rotary rod is 648.70 MPa, therefore the rotary rod may partially yield.

Analysis of a Concrete Structure that Was Exposed to Fires in the Metropolitan Region of Recife

In large cities, news about fires in buildings are powered by problems such as old wiring and no maintenance. Accidents with chemicals and human error, which when added to the different characteristics of each fire and structures can generate the factors causing these disasters. The gradual rise in temperature causes a different effect in mortar and concrete parts, verifying the change in coloring provided to loss of mechanical strength and surface crumbling, cracking and disintegration of the structure itself. This paper presents a case study in which a building that is located in the metropolitan region of Recife was exposed to a fire situation. The metropolitan region of Recife is composed of several old buildings that by virtue of their age may have delayed construction methods, and may expose the fragility of the concrete used in its construction on a fire situation. The concrete structures are recognized by the good resistance to fire because of the thermal characteristics of the material, however, the temperature rise in the concrete elements in characteristic causes a reduction in strength and modulus of elasticity of the material, the loss in stiffness leading to polyphase degradation of reinforced concrete, structural parts can lead to ruin, but when properly sized and executed, the concrete can serve as a proactive agent to be exposed to high temperatures, as the same may be subjected to high temperatures accidentally or they may be part of their normal work.