Analysis of spot defects on the surface of a cold-rolled Fe-36%Ni alloy strip

Many spot defects were found on the surface of a cold-rolled Fe-36%Ni alloy strip produced in a factory,which seriously affected the surface quality of the product.Through metallographic microscopy and scanning electron microscopy analyses,it was found that the spot defects were caused by the residual oxide layer on the surface of the cold-rolled Fe-36%Ni alloy strip after hydrogen annealing.By properly increasing the grinding amount of the blank before cold rolling to remove the oxide layer,the spot defects on the surface of the cold-rolled strip were effectively eliminated,and the surface quality of the product was ensured.

Two-stage treatment process of pickling wastewater in the cold-rolling production of stainless steel

Based on the characteristics of pickling wastewater in the cold-rolling production of stainless steel, a new processing route, featuring source sludge reduction, wastewater two-stage treatment, heavy metal-contained sludge and calcium salt sludge separating recovery, was proposed. As shown by the research results, after the two-stage process treatment, the effluent water can steadily reach the emission standards, the sludge yield can be decreased by more than 8% ; within the heavy metal-contained sludge, the recovery rates of Fc,Cr and Ni can either reach or surpass 95% ,and the total content ofF and S can drop to around 3%. Therefore,the sludge in the front part can be used as ferric dust. In the calcium salt sludge ,the recovery rate of F can either reach or surpass 85% ,and the total contents of Fe,Cr and Ni can fall below 0.5%. So the sludge in the rear part can be used as fluorgypsum or fluorite. Meanwhile,the results of the analysis on heavy metals leaching toxicity and morphologic distribution indicate that the two kinds of sectionalized sludge are not classified as hazardous wastes, which have a stable behavior and better utilization values compared with the former mixed- sludge.

Study on metallurgical properties and pellet proportioning technology of stainless steel cold-rolling sludge

With a complicated composition, large rolling sludge has been a focal point concerning neither at home nor abroad have any technologies suitable for bulk utilization of stainless steel cold- production and serious damage to the environment, stainless steel cold- environmental protection for stainless steel enterprises. Up to now, come into being that are not only proper, safe and economical but also rolling sludge. Based on the characteristics of the stainless steel cold- rolling sludge, orthogonal experiments were carried out on pellet proportioning and high-temperature roasting, and major metallurgical properties of sludge pellets were also tested. As the results show, pellets with 30% addition of cold-rolling sludge are qualified regarding their compressive strength, chemical composition and major metallurgical properties. No adverse impact happens to the blast furnace operation when sludge pellets account for 10% of the blast furnace raw materials. Therefore, the technical route applied in this paper is proved simple, feasible and environmentally friendly for cold-rolling sludge treatment.

Effects of cold-rolling reduction on the recrystallization texture and grain boundary of ferritic stainless steel

The study investigates the effects of cold-rolling reduction on the recrystallization-annealed Nb ＋ Ti stabilized ultra-pure ferritic stainless steel with 21% Cr in regards to its microstructure evolution, grain size,recrystallization texture, and grain boundary characteristic distribution and disorientation angle. The research employed the electron back scattered diffraction technique and its results have shown that the average grain size was reduced and the {111 / 〈 112 〉 component was strengthened,which rotated towards {5541 〈225 〉 and {4451 〈384 〉 ,with an increasing cold-rolling reduction. The number fraction of the low-angle grain boundary and the coincidence site lattice （CSL） boundary ,which was mainly made up of ∑3,∑7∑11 and ∑13b, also increased.

Effect of deformation twinning on the evolution of texture in TWIP steels during cold-rolling

Texture evolution of high-manganese twining-induced plasticity (TWIP) steels (Fe-16Mn-0.6C) during cold-rolling is studied by means of quantitative orientation distribution function (ODF)analysis.Thickness reductions of the specimens during cold-rolling are 10%,20%,30%,50% and 65%,respectively.Evolution of texture is of the Brass type,which is typical for low-stacking fault energy (SFE) materials.The contribution of deformation twinning to the development of texture is clearly illustrated by the monotonic increase of the twinned Cu component.In the present study,the deformation twinning was identified as significantly contributing to deformation up to the maximum reduction applied.These results are useful for the prediction and control of the texture in TWIP steels.

Research and application on the automatic measuring device for testing transverse thickness difference of cold-rolling steel sheet

Many advanced technologies have been applied in developing the automatic measuring device for testing transverse thickness difference of cold-rolling steel sheet,such as the technologies of automatic control,sensor measurement,marking identification,photographic location,computer application and information transmission.This measuring device can measure the transverse thickness difference of the steel plate accurately and quickly,with a high detection level of automation.It is an effective detection equipment for transverse thickness control of steel plate.Horizontal width of steel plate measuring 0.8-1.4 m, horizontal measurement point positioning accuracy±0.02 mm,thickness range 0.2-2.0 mm, measurement accuracy within±1μm.

斜轧轧管与皮尔格轧管对大口径薄壁无缝钢管性能影响

通过对斜轧轧管机组生产的φ813 mm×28 mm规格和皮尔格轧管机组生产的φ711 mm×24 mm规格的15CrMoG无缝钢管的化学成分、常温拉伸、高温拉伸、硬度、冲击和金相组织等试验分析,研究了斜轧轧管与皮尔格轧管两种不同无缝钢管轧制方式对大口径薄壁无缝钢管性能的影响。结果表明:在相近轧制比的前提下,两种轧制方式对常温拉伸、高温拉伸及硬度等性能指标无影响,斜轧轧管方式生产的15CrMoG无缝钢管,其横纵向性能差异较小,冲击韧性更优。

利用最大熵(MaxEnt)模型对红豆杉潜在适生区的模拟

为了研究红豆杉(Taxus wallichiana var.chinensis(Pilger)Florin)的保护和繁殖,利用红豆杉存在记录与环境因素,利用最大熵(Maxent)模型,使用红豆杉分布数据,气象以及地形数据,分析影响红豆杉分布的主导环境要素,模拟红豆杉在我国的潜在适宜区,并结合我国自然保护区分布范围进行分析。研究结果表明:共提取了6个影响红豆杉潜在适生区的主导环境因素,分别为5月平均降水量、4月平均降水量、9月平均降水量、高程、坡度、3月平均降水量,红豆杉的潜在适生区是气候与地形的共同作用结果,春季降水量、高海拔与一定的坡度区间是影响红豆杉分布的主要因素;构建的最大熵模型的评价指标受试者工作特征曲线下面积(AUC)为0.933,表明该模型模拟结果精准,生成的红豆杉适生区结果可信;红豆杉的高适生区主要分布在鄂、陕、渝、湘、黔交界处以及闽、浙、赣交界处,高适生区多以高海拔山区为主;高适生区与中适生区分别有6.27%与4.82%的面积处于自然保护区范围内,可以针对部分高适生区的自然保护地对红豆杉进行就地保护与引种栽培,科学制定红豆杉的保护方案。

Pilger冷轧管机动态静力分析

通过对Pilger冷轧管机主传动系统的动力学分析,建立主传动系统的数学模型。以ADAMS为平台,结合Pro/E中的三维实体模型,建立某冷轧管机主传动系统动力学虚拟样机,并进行仿真计算和结果分析。获得考虑轧制力分布的该冷轧管机主传动系统的动力学特性,为Pilger冷轧管机的设计提供参考。

Effect of cerium alloying on microstructure,texture and mechanical properties of magnesium during cold-rolling process

Hot-extrusion and cold-rolling were conducted on Mg-Ce binary alloys to explore the effect of cerium(Ce)on microstructure,texture and mechanical properties of Mg alloys.The addition of Ce results in significant grain refinement both in as-cast and hot-extruded samples.The basal texture is also weakened after extrusion and an inclined basal texture is formed with Ce addition.The strength and elongation of the Mg-Ce alloys are improved simultaneously due to such grain refinement and texture weakening effect.After cold-rolling,plenty of twins are found in the pure Mg and AZ31 plates while grains in the Mg-0.3Ce plate deform more uniformly without lamellar twin structure.Furthermore,Mg-0.3Ce alloys own strong and continuous strain hardening because Ce atoms and Mg-Ce precipitated phases serve as obstacles for dislocation slip.

Effect of water quenching processing parameters on the mechanical properties of a cold-rolled C-Mn-containing steel sheet

Cold-rolled advanced high-strength steel sheets have become the material of choice for the automotive industry because of their unique attributes of high strength and balanced mechanical properties.High-hydrogen gas jet cooling and water quenching are the most commonly used ultrafast cooling technologies for producing martensite-containing high-strength steel sheets.The water quenching technology ensures the fastest industrial cooling rate of 1 000 K/s;therefore,it has the highest potential with respect to saving alloys.In this study,the water quenching of a C-Mn-containing steel sheet is simulated during continuous annealing to investigate the effect of water quenching and tempering parameters on its mechanical properties.The results reveal that at low quenching temperatures,the strength of the steel sheet decreases as the soaking temperature increases.However,at high quenching temperatures,a high soaking temperature corresponds to increased strength after quenching,regardless of whether the material was austenitized in the single austenite zone or the inter-critical zone.Therefore,a high quenching temperature always results in a high strength and a high yield ratio after quenching.Low-temperature overaging(tempering) considerably influences the yield strength and yield ratio,and the extent of this influence is correlated with the soaking temperature.

Fracture Behavior of TiNi Based Shape Memory Alloy Cold-rolled Tube

The microstructures and interracial characteristics of matrices at the inwalls and the out-walls of the cold-rolled tube with different amounts of deformation were investigated by the scanning electronic microscope （SEM）, the optical microscope （OM）, and the transmission electronic microscope （TEM） techniques. It was observed that as the amount of deformation increases, the flaws nucleate at the out-walls of the cold rolled tube, the stress-induced martensites change from （111 ） type Ⅰ twins to （011） type Ⅱ twins and then to （100） compound twins, nanocrystals and bulk amorphisation happen, the high density dislocation causes stress concentration at the out-walls of the Ti50Ni50 cold-rolled tube, and then precipitates its fracture, and the Ti2Ni particles strengthen the grain boundaries and curb the dislocation movements during plastic deformation. The inhomogeneity level of the grains in the Ti50Ni50 alloy plays an important role on the fracture of the Ti50Ni50 cold rolled tube.

Effect of annealing parameters on mechanical properties of cold-rolled martensitic steel sheets

Cold-rolled martensitic steel sheets produced on continuous annealing lines with water quenching facility,have advantages of high strength and low alloying element contents.These are in good accordance with the trend of light-weighting and fuel saving for automotive steel.In this article,a cold-rolled martensitic steel is studied to investigate the effect of annealing parameters on its mechanical properties.It is found that the quenching temperature and the slow cooling speed as well as the overageing temperature have significant influence on the strength of the experimental steel.The temperature zone at which the austenite decomposition is slow or has not started may be chosen as the quenching temperature to ensure the steel’s strength stability.The slow cooling speed also influences the steel’s strength greatly.A high cooling rate will lead to significantly higher strength.Tempering would decrease the steel’s tensile strength but would increase its yield strength.

Development and application of Baosteel's cold-rolled martensitic steel sheets

Cold-rolled martensitic steel sheets are becoming widely applied in the automotive industry because of their ultra-high strength,which may result in satisfactory weight reduction. The grades of martensitic steel sheets are classified based on their tensile strength,which ranges from 980 to 1 700 MPa. The main applications include a series of structural parts of uniform cross-section or simple shape,such as bumper beams,door beams and door sills,etc. The study and development of cold-rolled martensitic steel sheets date back to 2007 in Baosteel,and some grades became commercially available in 2009. By 2015,Baosteel had commercially supplied thousands of tons of these steel sheets with tensile strength up to 1 400 MPa. Currently,1 500 MPa martensitic steel sheet is commercially available and 1 700 MPa martensitic steel sheet has been successfully produced. The process technology and application guides of Basoteel ＇s cold-rolled martensitic steels are summarized and analyzed in order to assist ongoing research and ensure correct applications of these ultra-high strength steel sheets.

Fatigue Response of Cold-Rolled Type-304 Stainless Steel Foil

This study presents the fatigue response of 304 stainless steel foil, cold-rolled to a thickness of 3.2 μm with 87 percent cold work at orientations of 0, 45, and 90 degrees to the direction of rolling. Fatigue specimens were fabricated by laminating a supportive layer of 20-μm polyimide film to one side of the foil and patterning 242 crack initiation features by photolithographic process. Progression of fatigue damage was determined through electrical resistance measurement. The fatigue response was demonstrated to be largely affected by anisotropy existing between the rolling direction and the off-axis orientations. Fatigue cracks that traveled in a direction parallel to the elongated grains (cyclic loads applied at 90-degree orientation to foil rolling direction) had the most fatigue response (undesirable characteristic). The construction of the specimens with thin foil supported by a film backing contributed to high fatigue threshold.

Properties of ultra-low carbon,cold-rolled sheet steels containing titanium or boron for use in enameling

Ultra-low carbon（ULC）,cold-rolled sheet steels for porcelain enameling containing alloys of titanium and boron are studied. The microstructure,mechanical properties,inclusions,and precipitates of the sheet steels are analyzed. The hydrogen permeation time of the sheet steels as-annealed and after skin-passed or cold-rolled at different reductions are measured. It is show n that the sheet steels possess different features of enameling properties in hydrogen permeability,fishscale resistance,and pinhole resistance.

冷轧管机主减速机传动齿轮的过盈联接计算

冷轧管机主减速机具有降速增扭的作用,为节省制造成本,主减速机中的大齿轮采用组装齿圈式的结构,通过热胀法把齿圈与轮芯组装在一起,而齿圈与轮芯的过盈联接则非常重要,需经计算确定合理的过盈量。鉴于此,以某大型冷轧管机为例,运用经典力学理论对主减速机传动齿轮的过盈联接进行计算和分析,提供一种切实可行的计算方法。计算结果表明,该配合设计在足够的安全裕度下可保证动力传递且不发生滑移,该研究为冷轧管机主减速机传动齿轮的过盈联接提供了技术支撑。

冷轧管机孔型拆装方法及计算

冷轧管机孔型是生产无缝管的模具兼消耗品,成品外径不同需要配相应规格的孔型,同规格设备需配多套孔型来满足生产要求,在生产中孔型拆装频繁,因此选择合适的拆装方法及计算尤为重要,既要保证轧制力传递,又要避免装配时开裂,实现快速拆卸,缩短换型时间,提高生产效率。鉴于此,对热装孔型过盈量选择进行了计算,并介绍了拆装方法和特制的感应拆卸工具,以方便操作人员选择合理的拆卸方式,提高更换孔型的安全性,减少不合理装配造成的损失。

皮尔格冷轧管机轧制过程工艺优化

针对高速皮尔格冷轧管机轧制过程中轧制力波动及峰值大的问题,基于有限元仿真的方法,提出皮尔格冷轧工艺优化方案。首先,以316L不锈钢为研究对象,建立皮尔格冷轧管机冷轧过程三维有限元模型,分析了皮尔格冷轧管机轧制过程管坯外径与轧制力变化;其次,系统分析了皮尔格冷轧的轧制过程中送进量、管坯转动角度及辊缝间隙等工艺参数对轧制力的影响;最后,优选合理工艺参数,降低轧制力峰值及波动量。研究结果表明:316L不锈钢管坯在进入压下段后,轧制力及管坯轧制应力急剧增大;正反行程轧制力峰值及轧制力波动量随送进量增加而增大;当回转角度增大时,正行程轧制力峰值逐渐减小,而反行程轧制力峰值则先减小后增大,波动量在保持稳定后急剧增大;当辊缝间隙过大时,轧制力峰值呈现先增大后减小的变化趋势,前后行程轧制力波动量趋于稳定;当正行程送进量为6 mm,反行程送进量为1.5 mm,回转角度为55°,辊缝间隙为2 mm时,轧制力峰值降低23%,波动量减小至100 kN。

孔型设计对皮尔格冷轧316L不锈钢管塑性变形的影响

为满足皮尔格冷轧316L不锈钢管的高精度轧制技术需求,依据舍瓦金和米尔孔型设计原则,构建了两种轧辊孔型设计方案,并采用ABAQUS软件建立了多行程周期皮尔格冷轧过程的三维非线性有限元模型,模拟分析了316L不锈钢管从荒管到成品管轧制全程的金属塑性变形行为、轧制力演化及轧后残余应力分布等规律。结果表明,两种孔型的轧制力相当,管材应变随轧制进程逐步增加;采用米尔孔型时管材金属随周期送进和旋转发生了环向扭转,而采用舍瓦金孔型的金属环向塑性流动均匀,使得舍瓦金孔型轧制后管材的径向和环向残余应力相对较小。316L不锈钢管皮尔格冷轧后的尺寸及残余应力测试结果与计算结果一致,验证了数值模型的可靠性。