环孢素A治疗再生障碍性贫血对患者临床疗效、血常规指标及免疫功能的影响

目的探讨再生障碍性贫血(aplastic anemia,AA)患者采用环孢素A进行治疗对临床疗效、血常规指标及免疫功能的影响。方法随机选取2019年1月—2022年1月滨州市中心医院收治的80例AA患者为研究对象,根据随机摸球法分成观察组(n=40)与对照组(n=40)。对照组采用常规药物治疗,观察组采用环孢素A治疗,对两组患者的临床疗效、血常规指标、免疫功能、生活质量及不良反应进行比较。结果观察组的治疗总有效率(97.50%)高于对照组(80.00%),差异有统计学意义(χ^(2)=4.507,P<0.05)。治疗后两组白细胞(WBC)、血小板(PLT)、血红蛋白(Hb)水平明显增高,且观察组高于对照组,差异有统计学意义(P<0.05)。治疗后两组CD3^(+)、CD4^(+)水平明显增高,CD8^(+)水平明显降低;且观察组CD3^(+)、CD4^(+)水平高于对照组,观察组CD8^(+)水平低于对照组,差异有统计学意义(P<0.05)。治疗后两组世界卫生组织生存质量测定量表(WHOQOL-100)评分明显提高,观察组高于对照组,差异有统计学意义(P<0.05)。观察组不良反应发生率(5.00%)低于对照组(22.50%),差异有统计学意义(χ^(2)=5.165,P<0.05)。结论环孢素A应用于AA患者治疗中,可提高临床疗效,提高血常规指标,改善免疫功能,提升生活质量,减少不良反应发生。

Research on directly cold-rolled AISI 304 stainless steel strip with the twin-roll strip casting process

In order to improve the surface quality and properties of AISI 304 stainless steel strip produced with the twinroll strip casting process,the strip was directly cold-rolled. The results show that cold rolling clearly improves the surface roughness,microstructure and properties. Residual δ ferrite is greatly decreased, anisotropy becomes less obvious and corrosion resistance is greatly improved. These results demonstrate the feasibility of directly cold-rolled AISI 304 stainless steel strip.

An overview of strain ageing in low carbon steels

Strain ageing in steel was first observed during the 19th century when the maximum load carrying capacity of a test piece was increased after it had been retested following a previous series of testing in a plastic range. Over the last decades, a great deal of research has been performed to gain deeper insights into the phenomenon of strain ageing. The synergistic development of theoretical hypothesis and new experimental evidences has promoted the understanding of the mechanisms underlying strain ageing. The content of this paper is organized into four components. First, we have compared the main theories developed in recent years. Second, we have summarized the metallurgical effects on the strain ageing behavior observed in experiments. Moreover, we have made an attempt to correlate the experimental results and the above-mentioned theories. Third, we have proposed a feasible solution to control strain ageing in low carbon steels. Finally, we have elaborated the potentiality of the atom probe technique in facilitating direct characterization of the distribution of solute atoms.

Comparative study on the corrosion behavior of low alloy steels in sulfuric acid solution

The corrosion behavior of a weathering steel SPA-C and two acid resistance steels（ S-TEN1 and ND）in sulfuric acid solution was investigated by using potentiodynamic polarization and weight loss measurement techniques. Both potentiodynamic polarization and weight loss measurement tests indicated that corrosion resistance of these three alloy steels was as follows： ND ~ S-TEN1 〉 SPA-C. Surface analysis of the corroded samples conducted after the immersion test indicated that two layers were formed on the substrates, with the outer layer comprising FeSO4. H20 and the inner layer mainly comprising iron oxides. The addition of Cu, Cr, and Sb refined the corrosion products and improved the adhesion ability between the rust layer and the substrate.

Cause of stamping cracks in pure iron magnetic shielding covers

This study explores reasons for the random occurrence of stamping cracks during the production of pure iron magnetic shielding covers. Scanning electron microscopy and energy spectrum are used to observe cracks within parts, and results show significant brittle fracture morphology with chunks of manganese silicate and aluminum silicate inclusions present in the fracture surface. The chemical composition, mechanical properties, and microstructure are also analyzed for a corresponding batch of cold rolled pure iron sheet. The oxygen content of the material is found to be high,resulting in the random distribution of a large amount of long chain manganese silicate and aluminum silicate inclusions along the rolling direction, which corresponds to inclusions found on the fractured surface. The stamping cracks are thus assumed to be caused by the randomly distributed chain of inclusions within the cold rolled sheet. It is suggested that the amount of deoxidizer used should be more carefully controlled to decrease the inclusion contents and to thus avoid the recun＇ence of such defects.

Causes of progressive stamping die damage and retooling measures to reduce carbide punch fracture

We investigated the reasons for frequently appearing early failure of carbide punches in a progressive stamping die when they were used to produce magnetic shielding steel parts. The failure modes of the carbide punches were statistically classified. Edge chipping and shoulder fracturing were the two types of failure modes that were found. The composition, hardness, and microstructure of the punches were analyzed. The cobalt content was found to be too low to ensure sufficient toughness. The brittle phase of tungsten carbide （WC）was prone to breaking off during the shear cutting process, and resulted in edge chipping. In addition, the material chips were easily bonded to the punch edge when there was a lack of press oil lubricity. It resulted in an uneven blanking clearance, which caused a lateral force and finally resulted in shoulder fracturing of the punches. Improvement measures were introduced to address the abovementioned issues. By using the carbide punches with greater toughness and shear cutting oil with high lubricity, the early damage problems of the punches are effectively solved, which ensures normal production of the magnetic shielding steel parts.

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 05CuPCrNi 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 05CuPCrNi is lower than - 60 ℃. These results provide the basis for the use of this train body material in extremely cold regions.

Reasons and countermeasures for “marking problem” during the production of double-walled copper-brazed steel tubes

This study explores the reasons underlying the frequent appearance of ＂marking problem＂ during the production of double-walled copper-brazed steel tubes. To this end, we compared two types of copper-coated steel strips, of which one has almost no problem during production, whereas the other has higher number of incidences of ＂marking problem＂. We analyzed the chemical composition,mechanical properties,the cross-sectional metallographs, and surface quality of the trimmed edge in both types of specimen. After the roll forming process, the bonding condition between the steel layers of the tubes before and after brazing process has also been examined. Results indicate that the chemical composition and mechanical properties of the two kinds of strips are similar; however, the edge quality of the trimmed strips is significantly different. It is believed that the irregular shape of the edge portions in the strips will be more pronounced during the bevel treatment. Consequently, smooth and tight seams cannot be guaranteed by such uneven beveled edges,which lead to higher number of incidences of ＂marking problem＂ during production.

Effect of intercritical annealing temperature and cooling rate on the microstructure and mechanical properties of low-carbon aluminum killed steel

In this study, the intercritical annealing process for a typical low-carbon aluminum killed steel is investigated. A cold-rolled sheet was annealed at intercfitical temperatures ranging from 730 ℃ to 770 ℃ and then cooled in air or water. The annealed steel was then baked at 210 ℃, and its mechanical properties and microstructures were analyzed in detail. It is shown that after the air-cooling process,the strength of steel decreased and ductility increased with an increase in the annealing temperature. However, after water-cooling, the strength and ductility both increased with the increase of annealing temperature. These results are attributed to the property- optimization of the steel.

Preface

Due to retarded growth of global economy and an increase in the cost of raw materials, the competition for the market of iron and steel products is increasingly fierce,and influenced by a number of factors such as excess supply in domestic market. Cold-rolled steel sheets are mainly used for home appliances, packaging and construction, and so on, and they have generally entered a period of low growth over the world nowadays.

Numerical simulation of the temperature field of twin-roll thin strip continuous casting

In this study, the temperature field model of twin-roll thin strip continuous casting was developed, and the interface heat transfer coefficient between the air and the strip surface was computed by using the inverse method. The effects of the process parameters including the casting speed, liquid level height, pouring temperature and thickness of the thin strip on the outlet temperature of the rotating rolls and the surface temperature of the thin strip were analyzed.

A simple simulator and method for measuring transient interfacial heat transfer in the strip casting process

This study presents a simple simulator for measuring the transient interfacial heat transfer between the molten steel and the copper casting roll for strip casting. The calculation principle of the heat flux is introduced in detail. Results show that the heat flux reaches the peak value of 9 MW/m^2 ,and decreases rapidly to 4 MW/m^2, and then fluctuates within the range of 2 MW/m^2 to 5 MW/m2. It agrees with the previous study. It also indicates the simulator can be effectively used to analyze the heat transfer during strip casting.

EB态TA10钛合金高温变形行为及热加工图

以电子束冷床(EB)炉单次熔铸的TA10钛合金扁锭为研究对象,利用Gleeble−3800热模拟试验机开展高且宽应变速率范围(0.01~30 s^(−1))下的等温压缩试验,研究该合金在800~1000℃下变形60%时的高温力学行为及铸态组织演变特征,建立基于峰值应力的高温塑性本构方程,绘制考虑应变的热加工图,深入讨论能量耗散效率因子与宏观、微观组织、力学响应间的关联关系。结果表明:随着变形温度升高或应变速率降低,TA10钛合金流变应力减小;变形温度高于或低于相变点时,峰值应力与变形温度均呈线性相关。Arrhenius方程能较好地预测该合金变形抗力与工艺参数间的变化规律。该合金不适合单道次大变形,较为适合变形量中等且较慢应变速率下的成形方式,可尝试开展高速率多次小变形的方式成形。该合金在两相区慢应变速率下热变形时的流变软化机制为动态球化或塑性流动局部化,而高应变速率下应力塌陷现象的主要原因为宏观失稳,且其在单相区的软化机制以动态回复为主。

吉帕钢冷轧板形及厚度精度控制技术研究

针对吉帕钢冷轧板形及厚度精度控制的生产难题,设计出一种三次多项式与正弦函数组合的新型辊型,并开发出基于十八辊单机架轧制和冷连轧的目标板形动态设定控制技术,实现了多种超薄规格吉帕钢的稳定冷轧,最高轧制速度达到800 m/min;开发出基于性能前馈的吉帕钢冷轧厚度精度控制方案,包括新型AGC性能前馈控制轧制技术以及厚度扩展性能前馈控制轧制技术,成功用于吉帕钢十八辊单机架轧制和冷连轧轧制,带钢头尾厚度偏差在2%以内的控制能力提升达到37%。