Effect of Rare Earths on Precipitation Kinetics of Niobium Carbide in Microalloyed Steel

ＥｆｅｃｔｏｆＲａｒｅＥａｒｔｈｓｏｎＰｒｅｃｉｐｉｔａｔｉｏｎＫｉｎｅｔｉｃｓｏｆＮｉｏｂｉｕｍＣａｒｂｉｄｅｉｎＭｉｃｒｏａｌｏｙｅｄＳｔｅｌＹｅＷｅｎ（叶文），ＬｉｕＹｏｎｇｈｕａ（刘勇华），ＬｉｎＱｉｎ（林勤），ＣｈｅｎＮｉｎｇ（陈宁）（Ｄｅ...     

Breakdown Behavior of Eutectic Carbide in High Speed Steel During Hot Compression

 The evolution of eutectic carbide in as-cast M2 high-speed steel on different deforming conditions was investigated. Initially, specimens were deformed by hot compression in the range of 1223 to 1398K at strain rates of 0.01 to 1.0s-1. In a series of continuous deformation tests the flow stress curves were determined for the downstream process simulation. Subsequently, metallographic examination was carried out before and after deformed specimens for carbides analysis. As-cast microstructure is characterized as a spherical matrix of austenite and a continuous network of rodlike or irregular eutectic carbide, whereas deformed microstructure has broken carbide network and smaller granular products on all experimental conditions. It suggests that eutectic carbides fracture to particles during hot deformation by thermomechanical disintegration, while diffusion-controlled phase transformation was not remarkable. Combination with numerical simulation, the relationship between breakdown ratio of carbide network and deforming parameters were concluded. Strain was the most important one to shatter eutectic carbides and disperse products. Furthermore, critical strain values were obtained, beyond which carbide network disappeared, and fractured carbides kept a stable profile and deformed with matrix coordinately. A higher temperature or lower strain rate resulted in a lower critical strain.     

Effect of Adding Rare Earth Element on Cemented Carbide YT14 by Digital Image

ＥｆｆｅｃｔｏｆＡｄｄｉｎｇＲａｒｅＥａｒｔｈＥｌｅｍｅｎｔｏｎＣｅｍｅｎｔｅｄＣａｒｂｉｄｅＹＴ１４ｂｙＤｉｇｉｔａｌＩｍａｇｅＳｕｎＬｉｈｏｎｇ（孙丽虹）；ＨｅＣｏｎｇｘｕｎ（贺从训）；ＬｉｎＣｈｅｎｇｕａｎｇ（林晨光）；ＷａｎｇＹｏｕｍｉｎｇ（...     

Characteristics and Controlling of LaB_6-ZrB_2 Eutectic Microstructure

ＣｈａｒａｃｔｅｒｉｓｔｉｃｓａｎｄＣｏｎｔｒｏｌｉｎｇｏｆＬａＢ６ＺｒＢ２ＥｕｔｅｃｔｉｃＭｉｃｒｏｓｔｒｕｃｔｕｒｅＣｈｅｎＣｈａｎｇｍｉｎｇ（陈昌明），ＺｈｏｕＷａｎｃｈｅｎｇ（周万城），ＺｈａｎｇＬｉｔｏｎｇ（张立同）（ＮａｔｉｏｎａｌＫｅ...     

碳化物对H13钢退火软化的影响

利用扫描电镜、物理化学相分析和Ｘ射线衍射方法，测定了不同退火经工艺下Ｈ１３钢中基体的合金元素含量和碳化物类型、尺寸、分布、对对量以及退火硬度。明确了Ｈ１３钢退火后硬度的高低与碳化物粒子的大小、相对量及碳化物的类型的依赖关系。     

Effects of Rare Earth Elements on Properties and Structure of WC－14TiC－8Co Cemented Carbide

ＥｆｆｅｃｔｓｏｆＲａｒｅＥａｒｔｈＥｌｅｍｅｎｔｓｏｎＰｒｏｐｅｒｔｉｅｓａｎｄＳｔｒｕｃｔｕｒｅｏｆＷＣ－１４ＴｉＣ－８ＣｏＣｅｍｅｎｔｅｄＣａｒｂｉｄｅＨｅＣｏｎｇ－Ｘｕｎ；（贺从训）；ＷａｎｇＹｏｕ－Ｍｉｎｇ；（汪有明）；ＬｉｎＣｈｅｎ－Ｇｕ...     

Effect of Rare Earth Elements on Growth Dynamics of Austenite in 60CrMnMo Steel

６０ＣｒＭｎＭｏｓｔｅｅｌｉｓｕｓｅｄｆｏｒｍａｋｉｎｇｈｏｔｒｏｌｓ．Ｔｈｅｈｏｔｒｏｌｓｅｘｐｅｒｉｅｎｃｅａｌｔｅｒｎａｔｉｎｇｍｅｃｈａｎｉｃａｌ,ｔｈｅｒｍａｌａｎｄｆｒｉｃｔｉｏｎａｌｌｏａｄｄｕｒｉｎｇｒｏｌｉｎｇ．Ｉｔｓｂｏｄｙｉｓ...     

Accelerating Effect of Rare Earth in Steel on Its Surface Carburizing Process

Ｉｎｇｅｎｅｒａｌ,ＲＥａｒｅｂｅｎｅｆｉｃｉａｌｅｌｅｍｅｎｔｓｆｏｒｓｔｅｌｓｗｈｅｎｔｈｅｙａｒｅａｄｄｅｄｉｎａｐｐｒｏｐｒｉａｔｅａｍｏｕｎｔｓ［１～３］．Ｉｎｅａｒｌｙ１９８０ｓ,ｉｔｗａｓｆｏｕｎｄｔｈａｔＲＥｄｏｐｅｄｃａｒｂｕｒｉ...     

高速钢中的碳化物缺陷

 大量碳化物的存在是高速钢组织的重要特征,也是影响高速钢质量和性能的关键因素。碳化物颗粒细小、形状规则和分布均匀的钢其质量和性能都好。但是,钢中的碳化物并不都这样理想,往往存在缺陷。根据对W18Cr4V、W6Mo5Cr4V2、W9Mo3Cr4V和W2Mo9Cr4VCo8等钢中碳化物的研究结果,分析了高速钢中常见的几种缺陷：①碳化物分布不均匀;②颗粒尺寸粗大,形状不规则,多为角状等;③碳化物微裂纹;④碳化物粘连等;⑤二次碳化物稀少。另外,还分析了以上碳化物缺陷产生的原因和危害性,并指出了减少缺陷应采取的措施。     

Heterogeneous Nuclei of Intergrowth Eutectic in Austenite-Bainite Steel Modified by Ce and Al

ＨｅｔｅｒｏｇｅｎｅｏｕｓＮｕｃｌｅｉｏｆＩｎｔｅｒｇｒｏｗｔｈＥｕｔｅｃｔｉｃｉｎＡｕｓｔｅｎｉｔｅＢａｉｎｉｔｅＳｔｅｌＭｏｄｉｆｉｅｄｂｙＣｅａｎｄＡｌＸｕＺｈｅｎｍｉｎｇ（许振明）（ＤｅｐａｒｔｍｅｎｔｏｆＭａｔｅｒｉａｌｓＥｎｇｉｎｅｒ...     

Modifying Effect of Rare Earths and Titanium on Austenitic Manganese Steel

ＭｏｄｉｆｙｉｎｇＥｆｅｃｔｏｆＲａｒｅＥａｒｔｈｓａｎｄＴｉｔａｎｉｕｍｏｎＡｕｓｔｅｎｉｔｉｃＭａｎｇａｎｅｓｅＳｔｅｌＺｈｕＲｕｉｆｕ（朱瑞富），ＬüＹｕｐｅｎｇ（吕宇鹏），ＬｉＳｈｉｔｏｎｇ（李士同）ＣｈａｏＺｈｉｑｉａｎｇ（朝志强），Ｗａ...     

Mechanism of Improving the Wearability of WC78-TiC14-Co8 Cemented Carbide with Yttrium Addition

ＭｅｃｈａｎｉｓｍｏｆＩｍｐｒｏｖｉｎｇｔｈｅＷｅａｒａｂｉｌｉｔｙｏｆＷＣ７８ＴｉＣ１４Ｃｏ８ＣｅｍｅｎｔｅｄＣａｒｂｉｄｅｗｉｔｈＹｔｒｉｕｍＡｄｄｉｔｉｏｎＹｕａｎＹｉ（袁逸），ＷａｎｇＸｉｎｙｉ（汪新义）（ＤｅｐａｒｔｍｅｎｔｏｆＭａｔｅ...     

Effect of RE Oxide on Cracking Resistance of Hardfacing Metal

Ｓｉｎｃｅｎｏｔｏｎｌｙｔｈｅｈｏｔｒｏｌａｎｄｈｏｔｄｉｅｗｉｔｈｈｉｇｈｅｒｐｒｉｃｅａｒｅｃｏｎｓｕｍｅｄｉｎｌａｒｇｅｑｕａｎｔｉｔｉｅｓｂｕｔａｌｓｏｔｈｅｉｒｑｕａｌｉｔｙａｆｅｃｔｓｔｈｅｐｒｏｄｕｃｔｉｖｉｔｙ，ｔｈｅｙａｒｅｃｒｉｔ...     

锻造对DGJW40钢结硬质合金组织性能的影响

ＤＧＪＷ４０ 钢结硬质合金是一种采用新工艺制作的新型材料。对ＤＧＪＷ４０ 钢结硬质合金锻造前后的显微组织和力学性能进行对比分析与研究,结果表明通过锻造可使其得到有效改善。     

改善不锈轴承钢9Cr18共晶碳化物的工艺研究

采用金相显微镜分析了30 t EAF-LF-VD-Φ200 mm电极-Φ360 mm ESR锭-120 mm×120 mm锻坯-Φ50 mm轧材的冶炼和加工工艺对不锈轴承钢9Cr18共晶碳化物的影响,结果表明,模铸电极浇注温度由1500～1510℃降至1485～1495℃,电渣重熔熔速由4.5 kg/min降至3.5 kg/min,增强电渣重熔冷却条件,可以有效减少冶炼过程中的共晶碳化物原始形成。采用锻透力强、大变形开坯,可使大颗粒碳化物破碎、减小颗粒尺寸,降低碳化物条带和网状聚集程度,能够有效改善不锈轴承钢共晶碳化物评级,减小碳化物颗粒尺寸。     

Effect of titanium and rare earth microalloying on microsegregation,eutectic carbides of M2 high speed steel during ESR process

The effects of RE and Ti microalloying during electroslag remelting(ESR) process on the microsegregation and morphology of eutectic M_2C carbides in M2 high speed steel were investigated.The results show that the addition of 0.2 wt% RE can alleviate the segregation of C,W,Mo,V and Cr,while the morphology of eutectic M_2C carbides hardly changes.The microalloying with the addition of 0.5 wt% Ti has the lowest degree of microsegregation due to the improvement of primary dendrites by the effective heterogeneous nucleating agent of(Ti,V)(C,N) particles.The addition of Ti makes the mo rphology of M_2C carbides change from rod-like or maze-like shape into a coarse feathery shape,exhibiting anisotropic facet growth characteristics.For the microalloying of 0.2 wt% RE and 0.5 wt% Ti,the segregation of the main metal alloying elements is slightly more severe than that of the addition of only RE or Ti.Under the combined action of RE and Ti,the feathery eutectic M_2C becomes thinner and shorter and tends to be isolated or distributed in a discontinuous network.     

RE 对 ZnAl4 合金组织和力学性能的影响

在ZnAl4合金中添加RE元素对其进行变质处理,通过金相组织和力学性能分析,研究了RE对该合金的显微组织和力学性能的影响。结果表明,基体中加入适量的稀土后,优化了组织结构,细化了晶粒,使合金的强度、硬度提10%以上,延伸率也有一定的提高。     

高碳铬不锈轴承钢孪晶碳化物研究

研究了高碳铬不锈轴承钢“孪晶碳化物”（直线状和链状碳化物）的影响因素及形成原因,结果表明：加热温度达到1140℃,退火后开始出现沿晶界分布的链状碳化物;加热温度≥1160℃,退火后出现大量直线状和链状两种形态的碳化物。材料从高温直接冷却时,温度≥1080℃并且冷却速度≤80℃／h可能析出链状碳化物,并且温度越高冷却速度越慢析出的可能性就越大。直线状碳化物形成原因为：材料加热温度过高．晶粒长大的过程中晶界迁移时偶然发生堆垛错误形成了生长孪晶,在随后的退火过程中碳化物向奥氏体挛晶界面沉淀而形成,是真正意义上的孪晶碳化物。链状碳化物是由于材料过热或者局部过热,在随后冷却过程中碳化物沿奥氏体晶界析出而形成的,本质上是一种网状碳化物。     

稀土元素对奥氏体不锈钢焊条熔敷金属组织和性能的影响

在奥氏体不锈钢焊条中，通过在焊条药皮中加入稀土元素。探讨了其对焊条熔敷金属组织和性能的影响。对加稀土前后两种焊条进行了熔敷金属常规拉伸和冲击试验。宏观金相组织分析和冲击断口扫描电镜分析。并对熔敷金属薄片进行了透射电镜分析。结果表明：在奥氏体不锈钢焊条药皮中加入稀土元素。可以细化结晶组织，改变晶界上碳化物的析出形态和分布，并使碳化物的析出数量和颗粒尺寸明显减小，从而净化了奥氏体晶界，提高了其焊条熔敷金属的机械性能。     

CSP工艺生产低碳钢中的纳米碳化物及其对钢的强化作用

用化学相分析及x射线小角散射法研究了CSP工艺生产HSLC钢中碳化物的成分、数量及粒度分布,发现尺寸小于18 nm的碳化物含量大于文献中测定的CSP含Nb的HSLA钢中尺寸小于18nm的Nb (C_xN_y)含量.对纳米级碳化物对钢的强化作用进行了讨论.