镀层用热轧高强度结构钢板Q460DC的开发

通过对钢板化学成分、生产工艺、组织结构、力学性能、热镀锌性能和焊接性能进行研究,开发出镀层用热轧高强度结构钢板Q460DC。实际应用表明,该钢板综合性能良好,可满足热镀锌钢板塔制造的要求。     

Production of hot-rolled sheet of specified quality by a new slab-casting technology

New methods of producing continuous-cast slab cannot be based on equilibrium crystallization of the steel at low speed. If melt is supplied to the wall layers in the mold through a pressurized submerged nozzle with eccentric outputs, the solidification rate of the steel in casting may be significantly increased. The results show that the new technology ensures improved quality in casting slabs of large cross section. When using the experimental nozzle, the width of the columnar-crystal zone is reduced and the disoriented-crystal zone is enlarged, while less axial segregation is observed. In casting by the new technology, heat transfer in the mold is increased by 10–12%. Impact tests reveal characteristics of the metal that are not evident in other tests. Structure formation of the metal in the continuous finishing group of a continuous broad-strip mill and subsequent strip cooling are studied by physical modeling. Tapered low-carbon steel samples taken from slab cooled on the intermediate roller conveyer of the broad-strip mill are rolled in one and two passes on a tworoller high-speed laboratory mill with a bypass unit. The rolling processes are geometrically and kinematically similar. After a fixed holding time in air, the rolled samples are set on one edge by means of a special device for partial quenching in coolant solution. Gradations of reduction are produced over the length of the sample, and gradations of cooling rate are produced over the width. The results of physical modeling illustrate the structure formation in low-carbon steel on rolling and accelerated strip cooling on a continuous broad-strip mill. Using these results and the Hall–Petch equation, specified structure and yield point of the final hotrolled sheet may be ensured. By eliminating the additional slab heating before rolling and improving the product quality, considerable economic benefit may be ensured.     

Producing thin sheet materials of copper-tin powders

Conclusions A study was carried out on rolling powders of copper with 6.5% tin, sintering, compression rolling, and thermal stabilization of the strip. The thin strip of tin bronze is used as tools for cutting diamond crystals.Translated from Poroshkovaya Metallurgiya, No. 6 (66),pp. 95–97, June, 1968.     

Secondary work embrittlement of cold-rolled 05CuPCrNi sheet at low temperature

Due to the rapid development of China's rail transportation equipment manufacturing industry and related international distribution,important material suppliers such as Baoshan Iron Steel Co.,Ltd.carries on investigating the stability of material under extremely cold conditions.In this study,mechanical properties and secondary work embrittlement of weathering steel 05 CuPCrNi were tested at low temperature.Compared to the mechanical properties at room temperature,the yield and tensile strength increase slightly with decreasing temperature.However,the variation of elongation is not obvious.The experimental results also show that the secondary work embrittlement transition temperature of 05 CuPCrNi is lower than-60 ℃.These results provide the basis for the use of this train body material in extremely cold regions.     

High temperature hardness of tungsten carbide

The effect of crystallographic orientation and test temperature on hardness of WC single crystals was investigated along with the hot hardness of poly crystalline tungsten carbide. Also investigated was the effect of carbide grain size and the amount of binder phase on the hot hardness of some cemented tungsten carbides. The hot hardness of single crystal WC on all major crystallographic orientations evaluated decreases very rapidly for increasing temperature, and the single crystal hardness on its hardest orientation is only about half of the polycrystalline material depending on the test temperature. Because of its polycrystalline character, some cobalt bonded cemented tungsten carbides can be harder than single crystal WC over some intermediate temperature range.     

The influence of texture inhomogeneities on the plastic anisotropy of hot-rolled low-carbon sheet steel

Measurement of the r-value in low-carbon steel sheet with and without surface removal. Comparison with calculated values on the basis of the Taylor theory with pencil glide. Good agreement can be obtained if texture inhomogeneities are taken into account.     

热轧AZ31镁合金薄板的室温成形性

针对AZ31镁合金板材室温冲压成形较差的特点,采用不同轧制温度获得镁合金板材,使用半球形凸模胀形,绘制镁合金室温成形极限图并分析轧制温度对镁合金板材组织和室温成形能力的影响.发现AZ31镁合金板材的成形性能不仅与晶粒尺寸有关,还与晶粒取向有关.基面织构的减弱可明显提高板材的胀形性能,在基面织构强度相似的情况下,晶粒尺寸对板材的成形性能起决定性影响.     

Development and evaluation of a hot-rolled 780 MPa steel sheet with an ultra-high expansion ratio

This paper explores the development of a 780 MPa hot-rolled high-strength steel with an ultra-high hole expansion ratio(HER) by using a nanoprecipitation-controlled technology.Systematic analysis and evaluation of an industrially produced steel sheet have been performed to investigate the microstructure, nanoprecipitates, tensile properties, HER,bendability, and forming limit diagram.The newly developed 780 MPa hot-rolled high-strength steel sheet is composed of a fully ferritic microstructure o...     

热轧板热处理离线数据分析与管理系统的设计与实现

主要描述了热轧板热处理线离线数据分析与管理系统的功能、方案和特点。包括生产数据管理以及系统的实现过程。首先介绍了热轧板热处理生产线现状和存在的问题,以及热处理生产线组成结构和特点;其次介绍了离线数据分析与管理系统的目的是完善热轧板热处理工艺数据分析与管理系统,解决热轧厂热处理线的数据收集、查询、新工艺设计以及数据分析的难题;同时介绍了离线数据分析与管理系统硬件设计的方法、软件设计的构思和实施本系统采取技术手段;最后介绍了离线数据分析与管理系统的特点——通讯接口的规范性、系统功能的可扩展性、系统结构的合理性。     

Rational controlled rolling on a 5000 pipe-blank mill at reduced temperature

Effective controlled billet rolling on the OAO MMK 5000 mill permits the production of pipe for underground pipelines (diameter 1220 mm; wall thickness 22 mm) from steel of strength category X80. The slab temperature before rolling may be reduced to 1100°C, with corresponding adjustment in the rolling energy and with the required solubility of carbonitrides of the microcomponents, so as to ensure the required strength.     

化学成分及退火温度对镀锡板调质度的影响

采用50kg真空炉及模拟退火炉进行冶炼和退火试验,结合硬度、拉伸试验及金相分析,研究了镀锡原板中的w(C)和退火温度对调质度的影响。结果表明,在相同的退火温度条件下,随着镀锡原板中w(C)增加约0.001%,镀锡板的洛氏表面硬度值(HR30Tm)增加约5,其强度增加5～10 MPa,而伸长率下降约1.5%;在w(C)不变的条件下,随着退火温度的上升,镀锡板的洛氏表面硬度值下降。     

FeSi中铝对不锈钢连铸和热轧板表面缺陷影响

 针对硅脱氧条件下304不锈钢中出现的Al2O3夹杂物和热轧板表面存在分层缺陷的问题,通过对铸坯的大样电解、热轧板取样、扫描电镜检测分析以及FactSage软件计算等方法,主要研究了FeSi合金中残余铝质量分数对Al2O3夹杂物生成的影响,并分析了Al2O3夹杂物对不锈钢连铸和热轧板表面分层缺陷的影响。研究表明,硅脱氧条件下生产的304不锈钢整个冶炼过程中,产生Al2O3夹杂物的主要环节为GOR还原初期含有较高铝质量分数的FeSi合金的脱氧过程。通过FactSage软件计算得到了避免Al2O3生成时FeSi合金中所允许的最大铝质量分数。根据计算结果和现场试验得出以下结论：FeSi合金中的铝质量分数超过1.8%时,钢液中会产生Al2O3夹杂物,Al2O3进入具有较高碱度的结晶器保护渣熔渣层造成局部保护渣黏度和熔化温度快速增加形成块状的夹杂物,这些夹杂物被卷入钢液内部或者被新生铸坯表面捕捉,从而造成热轧过程中轧板的表面分层缺陷形成。当FeSi合金中的铝质量分数小于1.5%时,钢液中难以产生Al2O3类夹杂物,有效抑制了这类表面缺陷的产生。     

Influence of annealing on electrical resistance and hardness of hot-rolled aluminum alloy sheets containing up to 0.5% Zr

We investigated the influence of multistep up to 650°C on the magnitude of resistivity and hardness of hot-rolled sheets of low-alloyed aluminum alloys containing up to 0.5 wt % Zr. Experimental samples were formed in conditions approaching those implemented for industrial installations of continuous casting and rolling. Testing procedures, including heat treatment, are described. Metallographic analysis of a cast (initial) structure and the structure of experimental samples passing the deformation was performed. Dependences of resistivity (ρ) and hardness on the temperature of the last annealing step are constructed by the results of physicomechanical tests. It is established using the computational and experimental methods that the magnitude of ρ mainly depends on the zirconium concentration in the aluminum alloy. The optimal ratio between the zirconium concentration in the alloy and annealing temperature, which makes it possible to attain the best combination of characteristics of hardness and resistivity, is determined.     

FD级镀锌钢卷的表面质量控制

FD级表面镀锌IF钢是表面质量要求最高的镀锌产品,表面质量控制难度大,合格率低。其主要缺陷之一“线状”缺陷是炼钢内生夹杂或保护渣卷入引起的。控制“线状”缺陷的主要措施是洁净度控制和机清（火焰清理）。为了对比洁净度控制和机清措施的有效性,进行了IF钢镀锌钢卷表面质量控制试验。结果表明,机清对提高FD命中率的作用大于洁净度控制措施;没有经过机清的板坯,钢水洁净度控制措施、连铸液位波动和三路氩气背压控制的影响是明显的。试验过程发现的“机清翘皮”缺陷,是机清板坯表面毛刺或凸棱经轧制形成的。“机清翘皮”下方没有夹杂物,有时能够发现少量FeO。修磨等提高机清后板坯表面质量的方法有助于消除机清“翘皮”缺陷。     

Research and development of hot-rolled ultra-high strength steel at Baosteel

The effects of the composition and cooling process on the microstructures and properties of hot-rolled ultra-high strength low alloy(HSLA)steel,complex phase steel and martensite steel were studied in the laboratory.And S700MC and MP1200 ultra-high strength steels were trial produced at the 1 880 mm hot-rolling line of Baosteel.Compared with conventional hot-rolled high strength products,the idea that water is alloy was applied in the newly developed hot-rolled ultra-high strength steel.By the use of the economical composition design and controlled cooling after hot-rolling effectively,ultra-high strength steel of different steel grades can be obtained.     

Influence of post-weld heat treatment on the microstructure and hardness of laser weld seams on hot-rolled TRIP 800 steel

The transformation induced plasticity (TRIP) steels effect occurs because of the martensitic transformation of retained austenite during plastic deformation,and it provides the steel with excellent strength and ductility.While welding remains a vital part of auto body manufacturing,the weldability of TRIP steels is problematic,and this prevents its adoption for many applications in the automotive industry.This present work studies the effects of welding and post-weld heat treatment on the microstructure of TRIP steels.It is found that the microstructures of the fusion zone and the heat affected zone (HAZ) are changed after high-temperature heat treatment.Hardness tests revealed that fusion zone hardness decreased with increasing of temperatures in the post-weld heat treatment on the laser weld seam.The rolling performance of the welding seam and the seam of post-weld heat treatment were also studied.