Effect of Texture and Grain Size on Bio-Corrosion Response of Ultrafine-Grained Titanium

The bio-corrosion response of ultrafine-grained commercially pure titanium processed by different routes of equal-channel angular pressing has been studied in simulated body fluid. The results indicate that the samples processed through route B_c that involved rotation of the workpiece by 90 deg in the same sense between each pass exhibited higher corrosion resistance compared to the ones processed by other routes of equal-channel angular pressing, as well as the coarse-grained sample. For a similar grain size, the higher corrosion resistance of the samples exhibiting off-basal texture compared to shear texture indicates the major role of texture in corrosion behavior. It is postulated that an optimum combination of microstructure and crystallographic texture can lead to high strength and excellent corrosion resistance.     

热处理工艺对冷轧热镀锌双相钢组织与性能的影响

在实验室试制了热镀锌冷轧DP590双相钢,分析了临界区退火温度对双相钢组织性能的影响,并将同种成分的实验室试制双相钢与工业生产双相钢的组织性能作对比,结果表明:热镀锌双相钢在镀锌段易出现贝氏体组织,且随临界区温度的上升,贝氏体组织含量增多,双相钢的强度上升,而塑性下降;工业试制双相钢,贝氏体和马氏体交互附着在铁素体晶界上,它们的体积分数约占29%,抗拉强度为610MPa,伸长率为31.5%,各项性能符合要求。研究得出,通过控制第二相(马氏体+贝氏体)体积分数和分布形态,能够充分改善热镀锌双相钢的力学性能。     

可逆式冷轧对钢板织构及铁素体晶粒尺寸的影响

在实验室通过可逆式和连续式冷轧及退火模拟试验,研究了可逆式冷轧对DX51D（低碳铝镇静钢）和DX54D（无间隙原子钢）钢板织构及铁素体晶粒尺寸的影响。试验结果表明：①可逆式冷轧态试样α取向线{115}、{335}织构密度明显大于冷连轧试样,可逆式与连续式冷轧态试样γ取向线{111}织构密度无明显差别;②DX54D可逆轧制退火态试样γ取向线{111}织构密度大于冷连轧试样,其α取向线织构密度则与冷连轧试样相当;③DX51D可逆轧制退火态试样织构密度与冷连轧试样相当;④可逆轧制退火态试样的铁素体晶粒尺寸小于冷连轧试样。     

Effect of NiCl2-Base Fluxes on Interfacial Layer Formation of Hot-Dip Galvanized Steels

 While the thick growth of intermediate phase layers generally benefits the corrosion resistance of galvanized steels, it is unfavourable from the standpoints of mechanical integrity and economics. The present study investigates the role of nickel chloride-base fluxes, in relation to the typical zinc-ammonium chloride flux, in the reduction of galvanized coatings' thickness and the effect on coatings' morphology and compositions. The investigation of pretreated galvanized steel specimens hot-dipped for various durations has verified that nickel chloride fluxes influence the growth rate of the zeta interlayer. This results in the overall-reduction of the coating thickness by as much as two times compared to those prepared with the conventional flux. Nickel from the fluxes gradually diffuse away from the substrate's surface, and hence the initial concentration of the nickel salts along with the hot-dip duration need to be controlled appropriately for effective use of nickel chloride-base fluxes in the galvanizing process.     

热镀锌表面锌凸起的成因及其形成机制

镀锌板表面出现条状锌凸起,通过现场试验跟踪以及金相组织分析,发现出现凸起的地方基板都存在裂纹、划伤等缺陷;根据晶体结晶形核和生长理论,初步分析由于基板存在缺陷,使锌液在此处结晶时,极易形核和生长,造成镀锌板表面出现条状凸起。     

镀锌钢板灰色镀锌层缺陷形成机理分析

针对热镀锌钢板表面出现的灰色镀锌层缺陷,使用电子探针(EPMA)进行缺陷镀层断面WDS形貌显微分析和成分分析、使用扫描电子显微镜进行缺陷镀层表面SEM微观形貌分析和EDS成分分析,并结合热镀锌镀层形成机理,提出了连续热镀锌过程中由于带钢及锌锅温度过高,锌锅中铝含量过低以及带钢表面粗糙过大,促使铁-锌合金渗入带钢表面而形成镀锌层灰色镀层缺陷。     

卷取温度对低碳铝镇静钢热镀锌板抗时效性能的影响

 针对低碳铝镇静钢连续热镀锌板抗时效性能较差的问题,通过镀锌板时效指数测量和内耗测量研究了卷取温度对抗时效性能的影响。试验结果表明,在620～710℃,随热轧卷取温度的提高,镀锌板固溶碳含量降低,抗时效性能提高,卷取温度从620℃提高到710℃,镀锌板时效指数降低19%。适当提高热轧卷取温度是改善低碳铝镇静钢热镀锌板抗时效性能的有效手段之一。     

0018Ni循环相变过程对性能及晶粒显示的影响

研究0018Ni管材循环相变过程中组织、性能变化趋势,找出挤压后的热处理工艺对成品管性能及晶粒大小的影响关系;找到了导致化学腐蚀与电解腐蚀的晶粒形态差异的本质原因是热处理过程循环相变不充分。这种不充分明显降低性能指标,尤其是塑性指标。     

可逆式冷轧对钢板织构及铁素体晶粒尺寸的影响

在实验室通过可逆式和连续式冷轧及退火模拟试验,研究了可逆式冷轧对DX51D(低碳铝镇静钢)和DX54D(无间隙原子钢)钢板织构及铁素体晶粒尺寸的影响。试验结果表明:(1)可逆式冷轧态试样α取向线{115}、{335}织构密度明显大于冷连轧试样,可逆式与连续式冷轧态试样γ取向线{111}织构密度无明显差别;(2)DX54D可逆轧制退火态试样γ取向线{111}织构密度大于冷连轧试样,其α取向线织构密度则与冷连轧试样相当;(3)DX51D可逆轧制退火态试样织构密度与冷连轧试样相当;(4)可逆轧制退火态试样的铁素体晶粒尺寸小于冷连轧试样。     

退火工艺对高温轴承钢M50钢材晶粒度的影响

晶粒度大小是衡量M50轴承钢质量的重要指标,通过探讨退火工艺对M50钢晶粒度级别的影响,以期改善实际生产过程中高温轴承钢M50钢材晶粒粗大、混晶问题。试验结果表明,适当提高退火温度、延长保温时间不会对M50钢晶粒度级别造成不利影响。实际生产中进行验证,退火工艺由860℃下保温5 h变更为910℃下保温8 h,可以改善因炉温均匀性差造成的M50钢材晶粒粗大及混晶等问题。另外,验证了当退火保温后的冷却速度过快,容易造成成品轴承淬火晶粒粗大,在实际生产过程中应予以关注。     

拉拔工艺对热镀锌钢丝性能的影响

介绍了拉拔工艺热镀锌钢丝σ、δ和扭转性能的影响,指出合理的拉拔工艺能改善热镀锌钢丝的综合力学性能。     

Effect of Initial Grain Size on the Evolution of {001}?100? Texture in Severely Deformed and Annealed High-Purity Nickel

Development of cube texture ({100}〈001〉) was studied in high-purity Ni (99.97 pct) with widely different starting grain sizes (~28 and 650 μm) following ultrahigh straining (ε _eq  = 6.4) by accumulative roll bonding (ARB) and annealing. The fine-grained starting material (FGSM) develops a much stronger cube texture after different annealing treatments as compared to the coarse-grained starting material (CGSM), despite their very similar bulk deformation texture. A lamellar type deformation structure is observed in both these materials, but the CGSM shows a more fragmented structure and frequent presence of shear bands. The recrystallization texture of the two materials differs right from the onset of recrystallization: cube-oriented grains nucleate and grow in the FGSM in sharp contrast to the nucleation and growth of randomly oriented grains in lamellar as well as shear-banded regions of the CGSM. The observed differences in the evolution of recrystallization texture in the two materials are discussed with regard to the microstructural differences and pertinent theories on the formation of cube texture.     

Effect of Nucleant Particle Agglomeration on Grain Size

Metallurgical and Materials Transactions A - Solute accumulation/depletion in the liquid around a growing solid particle during the solidification of metallic melts creates a constitutionally...     

Correlation Between Texture,Grain Boundary Constitution,and Corrosion Behavior of Ni-Cu Coatings

Metallurgical and Materials Transactions A - Nickel-Copper (Ni-Cu) coating with different Cu contents (2 to 7 wt pct) was electrodeposited over a mild steel substrate. Corrosion properties...     

回火对超细贝氏体晶粒取向和尺寸的影响

用50kg真空感应炉冶炼的钢锭,经1150℃开轧,两阶段控制轧制,830℃终轧成12mm钢板,驰豫27s,720℃进水快冷(冷却速率30～35℃/s)后,超低碳贝氏体钢(成分%:0.023C、1.63Mn、0.52Cu、0.25Mo、0.055(Nb+Ti)、0.0011B)具有板条贝氏体+少量粒状贝氏体和不规则铁素体的复合组织,贝氏体束团尺寸为3～5μm,块状和不规则铁素体尺寸为1～2.5μm。650℃和700℃回火对贝氏体晶粒取向无显著影响。     

硼对低碳钢晶粒尺寸的影响

研究了硼对低碳钢晶粒尺寸的影响,结果表明:低碳钢中酸溶硼([B]s)的质量分数大于0.005%时,随酸溶硼的质量分数增加,铁素体晶粒尺寸明显变大.主要原因为硼的加入使钢的奥氏体晶粒增大,从而使铁素体晶粒尺寸变大;硼的加入抑制铁素体形核并降低相变开始的实际温度,孕育期变长,从而使铁素体晶粒尺寸变大.冷却速度为0.5～5℃/s,随冷却速度加快,晶粒尺寸明显减小;冷却速度为5～15℃/s,晶粒尺寸的变化不大.冷却速度大于5℃/s时,含硼低碳钢明显出现贝氏体,因此热轧后盘条的冷却速度最好控制在5℃/s以下.     

退火与平整工艺对热镀锌深冲钢力学性能的影响研究

作为汽车及家电用钢重要组成部分的热镀锌深冲钢板,因其良好的冲压性能已得到广泛地应用。基于薄板坯连铸连轧工艺(CSP)所提供的超低碳钢原料,通过在马钢2号热镀锌机组进行不同退火温度、不同TV值以及不同的平整和拉矫延伸率试验,研究了其对产品力学性能的影响。在此基础上提出了采用IF钢而不采用超低碳钢作为2号热镀锌机组深冲钢原料的建议。     

Effect of Crystallographic Texture on Anisotropy of Yield Strength in X100 Pipeline Steel

The anisotropy of microstructures and mechanical properties in commercial American Petroleum Institute (API) X100 pipeline steel was systematically investigated by experimental measurements. The experimental results show that anisotropy of yield strength could be observed considerably, which should be attributed to the crystallographic textures due to deformation and transformation of texture components. This is because the effect of the inhomogencity of microstructure in different directions on the mechanical properties could be reasonably neglected based on the experimental investigation of grain size distribution. The effect of crystallographic texture on the anisotropy of yield strength was interpreted theoretically based on the relationship between yield strength and average orientation factor.