铝及铝合金熔体净化剂研究进展

介绍了铝及铝合金熔体净化过程中气体净化剂、排杂熔剂、精炼剂、覆盖剂等净化剂的研究现状,并初步分析了其在铝及铝合金熔体净化过程中的基本原理,同时提出铝熔体提高净化效果的主要途径及铝熔体净化剂的发展方向。     

40CrMnMo活塞杆的断裂

借助于光学显微镜和扫描电镜对 4 0CrMnMo活塞杆的组织、裂纹形态、断口的形貌以及活塞杆横截面的硬度进行研究 ,分析该活塞杆的断裂原因。结果表明 ,断裂的原因是材质不合格 ,存在成分偏析 ,热处理工艺不符合规定以及硫元素含量偏高。这就使得首先在偏析的边缘产生开裂 ,并且在轴向应力的影响下 ,裂纹沿着垂直于轴线的方向扩展 ,直至断裂     

ML08Al水口堵塞的研究与解决

研究了邯钢三炼钢方坯生产ML08Al浸入式水口堵塞的形成机制,分析了连铸浇铸过程中水口堵塞的影响因素,提出提高保护浇铸水平,对钢水夹杂物进行变性处理,对塞棒进行吹氩等措施,可有效防止水口堵塞,解决了堵水口的问题,稳定了生产节奏,也取得了较好的经济效益。     

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 冷轧板最主要的质量问题就是表面缺陷,亮带缺陷是目前首钢冷轧板最为常见的表面问题。通过研究不同亮带表面缺陷形貌及亮带处缺陷形貌、发生规律、元素构成、以及全流程缺陷的遗传性,分析了首钢冷轧亮带缺陷的主要原因,包括连铸坯皮下夹渣、皮下气泡、氧化铁皮压入以及辊印等因素。     

Inclusion behavior and microstructure of weld metal with Ce in twin wire high heat input submerged-arc welding

In this study,the welding thermal cycle curve exhibited two temperature peaks in high heat-input twin-wire separate-pool submerged-arc welding and coarse-grained heat affected zone existed in the welded joint. The inclusions of primary weld metal and coarse-grained heat affected zone of Ce-added SAW should be Al_2O_3,MnO,SiO_2,TiO,Ce_2S_3,CeS,Ce_2O_2S and Ce_2O_3. Under the effect of welding thermal cycle,oxy-sulfides inclusions of Ce,the diameter of which was less than 2. 0 μm,slightly grew larger,but the composition and type of the inclusions didn't change. The microstructure of the large heat input weld metal had acicular ferrite that Ce oxide sulphide particles induced nucleation and proeutectoid ferrite. In the coarse-grained heat affected zone of weld metal,home-position precipitation of acicular ferrite and sympathetic acicular ferrite were both observed. It was supposed that previous crystal cells of acicular ferrite in austenite grain promoted home-position precipitation of acicular ferrite. Meanwhile,sympathetic acicular ferrite tended to nucleate at the primary acicular ferrite grain boundaries,where high dislocation density was located,and grew inside the neighboring carbon-depleted austenitic regions. The granular bainite nucleated in the austenitic zone with high carbon content close to acicular ferrite and sympathetic acicular ferrite.     

Production of new welding fluxes based on silicomanganese slag

ABSTRACT

The properties of a welding flux based on the silicomanganese slag are investigated. The flux is produced using the slag formed in the production of silicomanganese with different ratios of the slag fractions and different content of the water glass in the flux addition. The addition of up to 20–30% dust fraction of the silicomanganese slag to the composition of the flux results in excellent mechanical properties of specimens taken from the welded plates. The FD-UFS addition reduces the extent of contamination with non-metallic inclusions and reduces the size and amount of these inclusions. The optimum content of the water glass in the flux (up to 20–30%) was determined. Consequently, the resultant mechanical properties of the specimens taken from the welded plates are very high.     

高频磁场电磁净化模拟

为了更准确地分析高频交变电磁场对金属熔体中的非金属夹杂物的去除效果,分别利用硅含量为18%、12.6%和10%3种铝硅合金所生成的尺寸为100、50和10μm的硅块来模拟非金属夹杂物以进行电磁净化实验研究.实验证明:生成的硅块可以更好地模拟金属液中单个的非金属夹杂物;施加电磁场后发现,电磁挤压力对单个尺寸在100和50 μm的非金属夹杂物的去除效果明显,同时也可以去除10 μm左右的非金属夹杂物.     

Ce变质处理提高Fe-Cr-Ni中熵合金抗点蚀性的研究

目的 研究Ce变质处理提高Fe-Cr-Ni中熵合金在3.5％NaCl溶液中抗点蚀性的机理.方法 通过动电位极化实验,分析Ca变质处理与Ce变质处理的Fe-Cr-Ni中熵合金的抗点蚀性.利用SEM和EDS等手段观察了经不同变质处理后合金中夹杂物的形貌和元素组成,并结合阻抗谱分析与XPS技术研究了Ce对钝化膜保护力的影响....     

分步酸溶法提取镍基高温合金粉末中非金属夹杂物的研究

本文提出利用分步酸溶法准确提取镍基高温合金粉末中非金属夹杂物,实现夹杂物的定量表征。首先选用最佳配比为HCl:HNO3=6:1的混合浓酸溶解镍基高温合金粉末,然后利用H2O2-草酸体系和稀酸将酸溶产物和难溶金属元素完全溶解。利用SEM、EDS等表征手段分析了最终获得的非金属夹杂物的数量、形貌、成分和尺寸分布,结果表明,该方法具有简便快速、分离效率高、回收率高、对非金属夹杂物的影响较小、可提取夹杂物粒径范围广等优点。此外,本文还对比了分步酸溶法和水淘洗法的提取效果,发现分步酸溶法对粒径大于50μm的夹杂物提取效果与常用的水淘洗法基本一致,而对粒径小于50μm的夹杂物提取效果显著提升。     

镁合金中的MgO夹杂物及熔剂精炼过程的研究

采用扫描电镜及电子探针对镁合金中单颗粒夹杂物进行了成分分析。结果表明：在MgO夹杂物内部，各处的成分并不均一，且夹杂物伴随着气孔产生。研究推导了单个夹杂物颗粒被熔剂裹覆后在镁合金液中的沉降速度表达式。得出了熔剂粘附层厚度与夹杂物沉降速度之间的关系，计算了夹杂物在镁合金液中的沉降速度，测定了精炼熔剂在试块上的粘附层厚度。通过对熔剂夹杂物成分的检测分析，证实了熔剂在精炼除渣过程中的作用。