试验参数对304不锈钢拉伸试验性能的影响分析

本文研究分析了不同试验参数（试验速串、引伸计标距、引伸计打开位置）控制下304不锈钢拉仲性能指标的变化情况．从而得到了304不锈钢弹性模量、屈服强度、抗拉强度、伸长事随试验速率的变化规律；不同控钊方式下涸得的断后伸长率与传统方法所测量的断后伸长率的结果比较情况。为正确使用全自动拉伸试验机进行程序编辑奠定了基础。     

S355J0WP耐候钢高温拉伸性能研究

为探索耐腐蚀钢在高温条件下的强度及塑性,本文研究了S355J0WP耐候钢在250℃及以上高温条件下的拉伸性能。试验结果表明：随着温度的升高,S355J0WP耐候钢的强度发生较大变化,具体表现为强度降低。但屈服强度和抗拉强度下降速率有所不同,屈服强度的下降速率快于抗拉强度。断后伸长率随着温度升高无明显变化,但当高温拉伸温度达到500℃时,断后伸长率出现一定幅度升高。随着温度的升高,圆拱形应力-应变曲线坡度逐渐变大。应力—应变曲线形状的变化主要是由于S355J0WP颈缩后的变形量总体上随着温度的提高而增大。     

拉伸试验速度对屈服强度的影响及控制

通过理论分析及实验数据，表明金属拉伸试验速度对屈服强度的影响。并依据国家标准，巾平均应力速率推导负荷速率计算公式，根据负荷速率可以简单、直观、方便地进行日常拉伸试验。确保试验结果的准确性。     

高温温度变化对Q370R钢板的性能影响

对Q370R进行了200～600℃温度下的屈服强度、抗拉强度等高温力学性能试验。通过试验发现,Q370R的屈服强度随试验温度的升高而降低,且温度在接近350℃时,屈服阶段基本消失;抗拉强度在200～400℃时,随试验温度的升高而增加;在400～600℃时,随试验温度的升高而降低。     

管线钢X70拉伸性能的对比试验分析

通过对比拉伸试验在不同取样位置、不同试样宽度、不同拉伸速率下所获得的性能数据,分析了取样位置、试样宽度和拉伸速率三方面对管线钢X70拉伸性能的影响。     

合金元素对双相不锈钢2101耐点蚀性能的影响

研究了合金元素对双相不锈钢2101耐点蚀性能的影响规律。结果显示,2101系列合金的浸泡点蚀腐蚀速率在1.9～7.0 g/（m^2.h）之间,与304不锈钢在同一数量级;Mo是提高2101系双相不锈钢耐腐蚀性的关键元素,而N对耐腐蚀性的影响不大;点蚀起源和Thermo-Calc计算结果显示2101成分体系中,铁素体相是耐点蚀性较弱相,提高铁素体相耐蚀性是提高合金整体耐蚀性的关键;当Cr含量固定在21.5%时,Mo作为铁素体形成元素将在铁素体相中富集,提高铁素体相的耐点蚀性能,从而提高合金整体耐蚀性。     

第二代单晶高温合金DD6的拉伸性能

研究了低成本的第二代单晶高温合金DD6的拉伸性能.结果表明[001]取向DD6合金的屈服强度与国外实际应用的第二代单晶高温合金的屈服强度相当;室温至760℃,DD6合金的屈服强度基本相同;在760～850℃范围内,随着温度升高,屈服强度提高;850℃时,合金的屈服强度达到最大值,即1030 MPa;当温度超过850℃后,随着温度的升高,DD6合金的屈服强度显著降低.     

表面处理对海洋工程用316L不锈钢耐点蚀性能的影响

316L不锈钢为常用的耐蚀合金材料,然而其在海洋大气环境服役时易遭受点腐蚀而发生失效。通过点腐蚀速率、临界点蚀温度、点蚀电位、极化曲线测试等评价方法,对经过不同表面处理(光亮退火、抛光、酸洗钝化)后的316L不锈钢的耐点蚀性能进行测试分析。结果表明,不同表面处理对316L不锈钢的临界点蚀温度影响不大,但会使点腐蚀速率、点蚀电位有所差异;在测试条件下,抛光及酸洗钝化均可有效提高316L不锈钢的耐点蚀性能,其中酸洗钝化态的耐点蚀性能最好,因此建议对海洋工程用316L不锈钢产品在使用前进行酸洗钝化处理。     

预变形对锆合金拉伸性能的影响

<正>北京航空材料研究院王旭等人分析了不同预变形量下退火态Zr-4合金的显微组织,研究了预变形量对退火态Zr-4合金室温和350℃下拉伸性能的作用规律,并通过扫描电子显微镜(SEM)及透射电子显微镜(TEM)对不同预变形量试样的显微形貌、位错组态及其分布情况进行了分析。拉伸试验结果表明:随着预变形量的增加退火态Zr-4合金在室温和高温下的屈服强度和抗拉强度均显著提高,断面收缩率和延伸率有一定的降低。对不同预变形量试样的显微形貌及位错分布情况的     

温度分布对铜基摩擦材料点蚀损伤的影响

通过离合器惯性实验台耐热实验,结合对非均质粉末冶金摩擦层结构模型和温度场的分析结果,研究了特定工况下的铜基粉末冶金摩擦副点蚀损伤现象,分析了温度分布对摩擦材料点蚀损伤的影响。结果表明:湿式铜基摩擦材料在长时间过载或热负荷集中时,由于摩擦表面产生局部高温,摩擦层内部产生较大的温度梯度和热应力,在铜基体与石墨接触区域会产生裂纹并出现铜基体的脱落与转移,发生点蚀;摩擦层上的点蚀程度由外侧向内侧逐渐加重后再减轻,中部点蚀现象最严重;在同一道摩擦层上,距离径向油槽较远区域的点蚀现象严重。     

不锈钢裸表面在氯化物溶液中的点腐蚀

研究了不锈钢去膜表面在氯化镁介质中的点腐蚀现象。去膜表面发生点蚀的临界电位低于膜覆盖表面发生点蚀的临界电位。去膜表面的点蚀主要在晶界和夹杂起源。点蚀形貌是敏锐的条纹状花样。根据作者提出的裸表面与氯化物介质反应步骤模型讨论了点蚀特征电位的意义以及裸表面点蚀形成的过程。     

Pitting Corrosion Behavior of Stainless Steel 304 in Carbon Dioxide Environments

The pitting corrosion behavior of stainless steel (SS) 304 in aqueous CO2-H2S-CI-environment was investigated by potentiodynamic cyclic anodic polarization and electron probemicroanalysis (EPMA). The experimental results show that the pitting corrosion susceptivityof SS 304 increases with the increase of temperature. Chlorine ion is the prerequisite for pittingcorrosion of SS 304 in H2S-CO2 environments. There is a linear relatiotxship between the pittingcorrosion potential (Eb-100) and chlorine ion concentration, and Eb-00 becomes noble with in-creasing pH value of the solution with or without H2S. pH value has little effect on the protec-tion potential with the presence of Hz S. H2S increases strongly the pitting corrosion susceptivi-ty and deteriorates the pitting corrosion resistance of SS 304 in CO2 environments. The obser-vations by EPMA show that SS 304 in CO2-saturated NaCI solution (3%) with H2S sufferspitting corrosion accompanied with intergranular corrosion.     

X80管线钢在西南地区土壤中的腐蚀电化学特征

采用电化学测试、SEM及EDS微观分析等方法,对X80管线钢在西南地区水饱和土壤中的腐蚀电化学特征进行了研究。结果表明,在水饱和西南土壤中,随腐蚀时间延长,X80钢腐蚀速率缓慢增大,腐蚀速度主要受氧扩散过程控制;EIS图谱具有双容抗弧与Warburg阻抗特征,电荷传递电阻和结合层电阻随时间而减小,腐蚀产物主要为铁的氧化...     

Prediction of Pitting Corrosion Mass Loss for 304 Stainless Steel by Image Processing and BP Neural Network

Pittingcorrosionisafrequentphenomenonen counteredinchemical,petroleumandmechanicalen gineeringandmanyotherindustrialapplication processes.Itcancauseinnumerableenergycon sumptionandeconomicdamage.Inordertoprevent ordecreasethepittingcorrosionofmetallicmate…     

Phase Transformation and Its Effects on Mechanical Properties and Pitting Corrosion Resistance of 2205 Duplex Stainless Steel

The effects of phase transformation on mechanical properties and pitting corrosion of 2205 duplex stainless steel were investigated. The amount of σ phase in the test specimen varied up to a maximum of 6% by thermal treatment at 850 ℃ for up to 60 min. The results showed that σ phase markedly increased the hardness and decreased the impact toughness of the test steel. But the increasing tendency of the ultimate tensile strength and the yield strength was not obvious, while the total elongation abruptly decreased with the aging time from 5 to 60 min. SEM impact microfractograph analysis revealed that the types of impact fracture changed from ductile mode to transcrystalline mode when the specimens were aged for 5-60 min. Furthermore, the extent of pitting potential reducing was found to be strongly temperature dependent, more pronounced at the higher temperature. During the incubation period of σ phase nucleation, the pitting corrosion test temperature and the aging time had collaborative effects on evidently displacing the pitting potential towards less noble values. After 15 min, the higher temperature contributed more to decreasing the pitting potential than the aging time.     

管线配套焊丝钢生产缓冷工艺研究

通过测定焊丝钢冷却过程连续过冷曲线,制定了管线配套焊丝钢盘条的冷却工艺。通过调整冷却工艺参数,使盘条强度满足了用户要求。拉拔试验结果表明,盘条可以不经过热处理直接拉拔到用户要求线径,拉拔后焊丝满足了用户缠绕与送丝要求。     

Effect of Temper Rolling on Tensile Properties of Low-Si AI-Killed Sheet Steel

The tensile properties of steel after temper rolling are affected by the reduction;low-Si Al-killed sheet steel was taken to study the effect of temper rolling on the tensile properties.The results indicate that the yield strength first decreases with the increase of reduction,and then increases.The relationship between the yield strength and the reduction can be expressed using quadratic function.The tensile strength increases with the increase of the reduction,while the total elongation decreases with the increase of the reduction,and the relationship between them and the reduction can be expressed using power function.Under the same condition,the results also indicate that the yield strength and tensile strength of steels across the rolling direction are all larger than those along the rolling direction; there is no obvious distinction between the total elongation along the rolling direction and that across the rolling direction.     

Effect of Temper Rolling on Tensile Properties of Low-Si Al-Killed Sheet Steel

The tensile properties of steel after temper rolling are affected by the reduction; low-Si Al-killed sheet steel was taken to study the effect of temper rolling on the tensile properties. The results indicate that the yield strength first decreases with the increase of reduction, and then increases. The relationship between the yield strength and the reduction can be expressed using quadratic function. The tensile strength increases with the increase of the reduction, while the total elongation decreases with the increase of the reduction, and the relationship between them and the reduction can be expressed using power function. Under the same condition, the results also indicate that the yield strength and tensile strength of steels across the rolling direction are all larger than those along the rolling direction; there is no obvious distinction between the total elongation along the rolling direction and that across the rolling direction.     

The Enhanced Even and Pitting Corrosion Resistances of Bulk Nanocrystalline Steel in HCl Solution

We studied the corrosion properties of bulk nanocrystalline 304 stainless steel (BN‐SS304) produced by severe rolling technique and conventional polycrystalline 304 stainless steel (CP‐SS304) with immersion test, X‐ray photoelectron spectroscopy, ultra‐violet photoelectron spectroscopy, inductively coupled plasma emission spectrometer, and scanning electron microscope. Immersion test was carried out in 0.5 mol L^?1 HCl solution for 30 days immersion interval at room temperature. It is well known that the pitting corrosion of stainless steel could be inevitable in solution containing Cl^?. However, BN‐SS304 can scarcely suffer from pitting corrosion with the compact oxide film on its corrosion surface and less corrosion rate in comparison with CP‐SS304. The less corrosion rate of BN‐SS304 was attributed to the stronger O₂ adsorption and compact oxide film on its corrosion surface, its less weight of 4s–4s valence electrons and its larger work function in comparison with CP‐SS304. The improved pitting corrosion resistance of BN‐SS304 resulted from the compact oxide film, weaker Cl^? adsorption and less Cl^? chemical activity on its corrosion surface.