2A97H14铝锂合金薄板表面缺陷分析及改善

2A97铝锂合金薄板的表面缺陷一直困扰其在航空领域的应用。采用扫描电镜、能谱分析对2A97H14铝锂合金薄板表面缺陷进行表征。结果表明：表面的微缺陷仅存在于表层位置，不是夹杂物等冶金缺陷，也没有影响到金相组织；去除约0.01 mm厚的表层，可基本消除表面缺陷。     

IF钢连铸板坯表面夹渣缺陷的研究

连铸过程结晶器内的保护渣卷入造成的非金属夹杂物尺寸大、靠近铸坯表面，成为轿车面板等高品质冷轧薄板的主要表面缺陷。本文对鞍钢三炼钢厂生产的IF钢连铸板坯表面夹渣缺陷的分布、形态及成分进行研究，观察到表面夹渣存在的两种形式。探讨了贯通型表面夹渣的形成机理，并提出减少表面夹渣的措施。     

CSP薄板坯连铸开浇炉次大型夹杂物研究与控制

某钢厂CSP薄板连铸生产高强汽车用钢、家电用钢等产品,开浇炉次卷板表面大型夹杂缺陷对产品质量造成严重危害,通过在中间包取样,采用扫描电镜、氧氮分析、光谱分析等手段,结合现场工艺参数,对产生夹杂缺陷的影响因素进行了分析研究。结果表明,造成CSP薄板坯开浇过程结晶器液面波动的主要原因为钢液二次氧化生成大量的夹杂物,以及钢液钙铝比控制不合理,造成钢液流动性变差。基于研究结果提出了相应的控制措施,开机炉次大型夹杂缺陷率降低了35.82%。     

镀锡板表面翘皮缺陷形成原因分析

为明确马钢镀锡板表面翘皮成因,对现场镀锡板进行了取样分析。缺陷取样检验分析结果表明,目前马钢镀锡板表面翘皮缺陷产生的原因主要是压氧（压入氧化铁皮）、非金属夹杂物和连铸结晶器保护渣卷入。同时,Parsytec表面质量检测系统因根据缺陷的图像判定缺陷类型,很难将条状圧氧和线状非金属夹杂分开,对夹杂缺陷的判定存在较大的误差。     

冷轧薄板表面长条形缺陷及其成因

一、问题的提出鞍钢生产的冷轧薄板质量一直比较稳定,但是从1985年以来,接连发生表面长条形缺陷。特别是在1987年2月,因2.5mm厚的30号冷轧板表面质量不合,用户向鞍钢提出质量异议。为分析这种缺陷产生原因,本文利用金相检验,扫描电镜观察和能谱对缺陷中夹杂物进行成分分析,研究了这种缺陷的形因。二、长条形缺陷的宏观特征在1.5～3.0mm厚的08A1或30号冷轧板表面,出现沿轧向呈长条形表面缺陷,如图     

低碳铝镇静钢冷轧板线状缺陷成因分析

利用扫描电子显微镜和能谱分析对低碳铝镇静钢冷轧板的表面缺陷进行了分析和研究。结果表明,缺陷主要是由高硬度、难变形的Al2O3夹杂引起的。根据生产工艺流程及现场情况预测了Al2O3夹杂来源,并提出了低碳铝镇静钢冷轧板表面质量的改善措施。     

冷轧薄板表面条痕缺陷成因及预防

为了提高冷轧薄板的成材率，研究了冷轧薄板表面条痕缺陷的宏观和微观特征，找出了炼钢、热轧、冷轧各工序可能导致缺陷形成的原因，并提出了相应的预防措施。     

DT辊辊颈典型质量缺陷原因分析及预防

介绍了我公司投料生产的个别DT辊锻件在机床加工过程中出现辊颈外露大面积夹杂物缺陷和调制前无损检测局部无底波典型质量缺陷问题,采用断口观察、扫描电镜等手段分析确定了质量缺陷问题产生的原因为内部裂纹和表面大量聚集的疏松缺陷.采取措施进行改进,有效防范质量缺陷问题再次发生.     

液/半固态双金属铸造复合耐磨薄板组织与性能研究

针对耐磨薄板难于实现大平面冶金结合和界面氧化夹杂难以去除的技术瓶颈,提出了液/半固态双金属铸造复合板制备的新工艺,以解决传统铸造复合工艺难于制备大面积耐磨板问题。通过制备的低碳钢/高铬铸铁(LCS/HCCI)复合耐磨薄板,研究了耐磨薄板界面层微观组织形成规律,通过装机测试分析了该耐磨薄板的使用性能。     

冷轧板SPHCZ钢表面缺陷原因分析与对策

结合现场实际生产过程,采用扫描电镜、金相组织、能谱分析等手段探讨了冷轧板SPHCZ钢表面缺陷的原因,并提出了相应对策。研究结果表明:主要表面缺陷为长条状表面缺陷和带状表面翘皮缺陷,长条状表面缺陷部位主要成分为Fe和O,无其他夹杂元素存在,该类长条状表面缺陷产生原因是轧钢生产过程中氧化铁皮压入钢板。带状表面翘皮缺陷部位主要成分为Al、Ca、K、Na、O、Fe和部分S等夹杂元素,带状表面翘皮缺陷产生原因是连铸过程中结晶器保护渣卷入钢中。通过增加粗轧清除氧化铁皮频次、细化精轧机架内检查制度、优化中间包吹氩制度,提高保护渣黏度等措施,SPHCZ钢表面缺陷率取得了显著的效果,由改进前的0.37%降低至0.12%。     

Reduction in area and appearance of hydrogen-assisted fracture surfaces of cathodically charged differnt Low-alloy sulphur containing steels

The present work is concerned with the role of sulphidic inclusions in hydrogen-assisted cracking of low-alloy steels with different sulphur contents. The steels were previously cathodically charged in sulphuric acid solution. Evaluating the susceptibility to hydrogen-assisted cracking in terms of the reduction in area values, the high sulphur steel is less susceptible than the low sulphur steel. The fracture surface of the low sulphur steel appears rather brittle, with local quasi-cleavage fractures around large intergranular fracture facets. In contrast, the fracture surface of the high sulphur steel is characterized predominantly by the microvoid coalescence mode, with a great number of manganese sulphide inclusions. The difference between the two sulphur steels is based upon the concept that the interfaces between sulphidic inclusions and matrix act as trapping sites for hydrogen and thus hydrogen is uniformly distributed over the sulphidic inclusions.     

AH32耐蚀钢显微组织对其腐蚀行为的影响

根据《油船货油舱耐蚀钢性能标准》规范,通过浸泡实验测量了AH32耐蚀钢在货油舱底部模拟环境中的腐蚀过程.采用失重测量、电化学极化与阻抗方法、扫描电镜和电子探针等手段,分析了AH32耐蚀钢显微组织对其腐蚀行为的影响.实验结果表明:模拟货油舱底板腐蚀实验中,AH32耐蚀钢的轧制面因珠光体所占面积分数小而腐蚀速率较低,其横截面则因珠光体面积分数大而造成腐蚀速度较快,而且二者的腐蚀速度均随浸泡时间的延长而加速.此外,轧制面表面有均匀腐蚀和因夹杂物溶解所形成的蚀坑,而横截面的腐蚀则沿条带状珠光体组织而有选择的进行.样品的珠光体区域在浸泡后有碳富集,这是造成腐蚀随浸泡时间延长而加速的原因.     

35CrMnSiA超高强度钢典型断口及原因分析

为了分析35CrMnSiA超高强度钢拉伸试样断面收缩率低的断裂机理和断裂原因,采用扫描电镜及能谱仪等对常见的4类断口进行了观察和分析。结果表明,一定量的氢和拉应力的共同作用产生的鱼眼缺陷是导致常规塑性断口断面收缩率低的主要原因。韧脆混合断口是由于在较大颗粒的夹杂物周围产生了氢脆,导致钢的断面收缩率下降。笔尖状断口主要是由于钢中大颗粒夹杂物或氢损伤缺陷造成的。脆性断口是由于机械标识对材料造成了损伤或氢在表面损伤处聚集形成了微裂纹。     

A Study of Homogeneity of Structure and Properties Over the Width of Sheets of Pipe Continuously Cast Steel 07G2FBYu

The effect of defects in the structure of a slab on the set of properties of sheet steel 07G2FBYu used for large-diameter electrically welded pipes for oil and gas pipelines is investigated. The structure and content of nonmetallic inclusions are studied at the edges and in the middle of slabs. Types of inclusions are determined. The effect of the mode of double hardening and high-temperature annealing on the microstructure of the steel is analyzed, including its variation over the sheet width. Changes in the strength, ductility, and resistance to brittle fracture, stress corrosion, sulfurated hydrogen corrosion, and hydrogen-stress cracking are considered. A hypothesis that the stress-corrosion cracking in electrically welded pipes serving in pipelines depends on the contamination of the edge zone of the sheet steel with nonmetallic inclusions is considered.     

浸入式水口结构对大方坯结晶器内夹杂物运动的影响

通过建立大方坯结晶器内钢液流动、传热、凝固和夹杂物运动耦合模型,研究了浸入式水口结构对结晶器内钢液流动和夹杂物运动的影响,比较了5种不同孔数的水口对应的夹杂物上浮、下沉以及坯壳吸附的比率和速率.研究结果表明:浸入式水口的结构很大程度上决定了结晶器内钢液的流动方式,进而决定了小颗粒夹杂物的运动轨迹.从水口底孔出来的射流中向上回流至液面部分的流股以及从侧孔出来的射流形成的螺旋上升的流股是促进夹杂物上浮的主要动力.只含侧孔的四孔型和双孔型水口在夹杂物去除方面能力最强,对于50 μm的小颗粒夹杂物去除率分别为25％和17％;而带底孔的水口(包括单孔型、三孔型和五孔型水口)去除率基本在10％以下.此外,对于含底孔的水口,铸坯内部夹杂物相对较多,而对于只含侧孔的水口,铸坯表面附近夹杂物相对较多.     

Analysis of surface topography changes in steel sheet strips during bending under tension friction test

In order to investigate the frictional behaviour and the change in surface roughness of different sheet topographies, a bending under tension friction test, BUT, was used. This test exposes the material to bulk-plastic deformation under conditions similar to those present in the drawing radius of a real tool. Each steel sheet material has been tested under different lubrication conditions. To measure the sheet surface topography a 3D stylus technique was used.For each steel strip the original surface, the area in contact with the tool and the resulting surface topography were measured. When comparing “standard” 3D surface roughness data for original and final surfaces, no correlation with friction data was obtained. However, with a special evaluation technique good correlation with oil retention volume and frictional behaviour was found for the surface in contact with the tool. By using measurements from the contact area, filtering the measured surface in two steps, firstly with a 5th degree polynom to get rid of the circular form and secondly with a ball filter to get rid of the waviness located in the topmost layer in the surface and then plotting the bearing area curve for the filtered surface on a probability paper, the real area of contact for each steel sheet surface can be determined, as well as the number of oil pockets and their mean area. The oil pockets were estimated by using a software in which areas of peaks were estimated, on a surface inverted at the level of the real area of contact.By plotting the mean area of the oil pockets versus the coefficient of friction for a sheet material with an excess amount of lubricant, a relationship is determined.     

彩钢板屋面渗漏水与大面积防腐处理

彩钢板屋面的应用越来越广泛,但是其中也存在着渗漏水与大面积腐蚀的问题,为此必须做好防水和防腐处理。笔者针对彩钢板屋面渗透水与大面积防腐处理的有效策略进行了研究。     

高强低合金钢H420LA表面条斑缺陷成因分析

针对高强低合金钢H420LA退火带钢表面存在的暗色条斑缺陷,采用SEM、EDX等手段对带钢表面正常区及条斑区进行了微观结构对比分析,并追溯了热轧态及模拟酸洗后带钢表面不同区域的宏观及微观形貌差别。结果表明：H420LA热轧带钢表面红锈缺陷可遗传演变为退火成品的表面条斑。通过对红锈缺陷的微观结构及其成因分析,提出了提高出炉温度、增加粗轧除鳞道次的工艺措施,有效地减少了H420LA热轧卷表面的红锈缺陷,冷轧成品表面质量因此得到改善。     

EFFECT OF RARE EARTH ADDITIONS ON FRACTURE PROPERTIES OF 2.25Cr-1Mo STEELS

The inclusion parameters,fracture surface morphology and void growth characteristics of ten-sile and fracture toughness specimens of 2.25Cr-1Mo steels with and without rare-earth(RE)additions have been investigated by quantitative metaltography(QTM),scanning elec-tron microscopy(SEM)and energy dispersive spectroscopy(EDS).There is a substantiallyhigher density of inclusions in the RE-treated steel,which has lower values of fracture proper-ties including critical values of COD and J integral(δ_c and J_(IC)),fracture strain(ε_f)and Charpy V-notch energy(CVN).The fracture surface of the RE-treated steel comprisesequiaxed dimples of diameters comparable with its inclusion spacing,whereas for thenon-RE-treated steels,a wide range of dimple sizes is found with average diameter muchsmaller than the corresponding inclusion spacing.The investigation indicates that the lowervalues of fracture properties for the steel with RE at room temperature may be ascribed to itslarge content of RE-containing inclusions.     

IF钢板坯表层大尺寸夹杂物的三维分布

IF钢铸坯表层大尺寸夹杂物分布对冷轧钢板表面质量有较大影响。采用ASPEX自动检测法与逐层刨削法研究了IF钢铸坯表层20 mm内中100 μm以上夹杂物的三维分布。铸坯表层20 mm内夹杂物共分成3类,气泡、氧化铝+气泡、块状氧化铝,数量比例分别为72%、26%和2%。结合水模型研究了结晶器内大尺寸夹杂物被凝固坯壳捕获行为,结果表明,在现有浇铸工况下结晶器内大尺寸夹杂物主要集中在上回流涡心处与浸入式水口下部等结晶器“死区”位置。消除结晶器内死区有助于减少铸坯表层大尺寸夹杂物,提高轧板表面质量。