(V,Cr, W)C复合粉末对WC-11Ni硬质合金微观组织及力学性能的影响

以Cr₂O₃、WO₃、V₂O₅和炭黑为原料，采用碳热还原法在1 500℃下反应2 h制备了(V,Cr, W)C复合粉末。采用XRD和SEM对(V,Cr, W)C复合粉末的相成分和显微组织进行了表征，研究了复合粉末的添加方式及含量对WC-11Ni硬质合金组织及力学性能的影响。结果表明，添加(V,Cr, W)C复合粉末的合金力学性能获得了显著提升，其抗弯强度、维氏硬度以及断裂韧性比未添加复合粉末的试样分别提高了19.97%、19.61%、12.18%。同时，添加(V,Cr, W)C复合粉末的合金性能优于添加(V,Cr)C复合粉末和添加WC+Cr₃C₂混合粉末的合金试样。另外，随着(V,Cr, W)C复合粉末添加量的增加，合金的抗弯强度、维氏硬度及断裂韧性均呈先增大后减小的变化趋势；当(V,Cr, W)C复合粉末的添加量为0.6%时，合金的抗弯强度、维氏硬度和断裂韧性达到最大值，分别为2 835 MPa、1 671 MPa、15.1 MPa...     

钛锶复合添加对汽车零部件压铸用模具钢性能的影响

对汽车零部件压铸用3Cr2W8V模具钢进行了钛锶复合添加改性,并对高温磨损试验和热疲劳试验结果进行了分析。结果表明:钛锶复合添加对3Cr2W8V模具钢的耐磨损性能和热疲劳性能产生了重要影响。与未添加钛锶的3Cr2W8V模具钢相比,添加了0.3%Ti和0.3%Sr的3Cr2W8V-0.3Ti-0.3Sr模具钢磨损体积、主裂纹平均宽度和主裂纹平均深度分别减小了35.7%、44.8%、57.1%,耐磨损性能和热疲劳性能得到明显提高。     

离子硫,氮,碳稀土多元共渗

对热挤压模具钢3Cr2W8V进行了基体强韧化处理以及表面离子硫、氮、碳加稀土共渗处理,分析其基体组织及表面层组织,进行了耐磨性试验。结果表明,加入稀土可有效地提高扩渗速度及渗层质量。由于表面形成了一层Fe_2S,在热挤压过程中有自润滑作用,从而大幅度提高了模具的耐磨性,显著增加使用寿命。     

稀土对Ti0.25V0.34Cr0.2Ni0.2合金相结构和电化学性能的影响

通过XRD, SEM-EDS等方法及电化学测试研究了稀土对Ti0.25V0.34Cr0.2Ni0.2合金的微观结构和电化学性能的影响. 结果表明, Ti0.25V0.34Cr0.2Ni0.2和Ti0.25V0.34Cr0.2Ni0.2RE0.01 (RE分别代表La, Ce, Pr, Nd和混合稀土)合金均由主相为体心立方结构的钒基固溶体相和少量TiNi基第二相组成. 稀土元素加入后, 合金bcc相的晶格参数略有增加; 镧在合金中发生偏析, 形成新相. 添加稀土元素能够加速合金的活化. 303 K温度下基准合金和含Pr合金电极实际测定的理论放电容量大致相等, 约为364 mAh·g-1. 合金的放电容量对温度的变化比较敏感, 高温有利于合金放电. 稀土对合金电极的荷电保持率产生不利影响; 混合稀土的添加能够改善合金的倍率放电性能.     

高强韧性热作模具钢4Cr3MoWVSiRE的性能

通过试验,本文对高强韧性热作模具钢4Cr3MoWVSiRE的室温、高温性能及使用结果进行了较全面的介绍,并与老钢种3Cr2W8V作了对比。结果表明该钢种综合性能,优于3Cr2W8V钢,用该钢制造的齿轮锻模,使用寿命较3Cr2W8V钢锻模提高一倍以上。     

EAF+VOD-ESR-825 mm轧机流程试制12%Cr型叶片钢

长城特钢采用 30 t EAF +VOD ESR(2～3 t锭 ) 825mm轧机试生产了 1Cr12Mo ,2Cr12NiMo1W1V等12%Cr型叶片用钢。结果表明 ,当 1Cr12Mo钢成分为 (%) :C 0.13～0.15 ,Cr 11.70～11.90 ,Ni 0.46～0.55 ,Mo 0.34～0.47,以及2Cr12NiMo1W1V钢成分为 (%) :C 0.22～0.25 ,Cr 11.30～11.68,Ni 0.67～0.95 ,Mo 0.96～0.99,W 0.96～0.98,V 0.22～0.25时 ,钢中的δ 铁素体含量δ_F ＜5 % ,满足标准要求。电极母材精炼时 ,用Ca-Si,Si-Al-Ba终脱氧有利于在电渣过程去除钢中夹杂物     

一种镍基单晶高温合金的显微偏析行为

研究了一种新型镍基单晶高温合金DD98铸态组织的显微偏析行为.实验结果表明,当合金以枝晶凝固时,组织中存在显微偏析.其中元素Mo、Cr、Ti、Ta、Al在枝晶间富集,Ti、Mo、Ta、Cr的偏析较为严重,Al的偏析程度相对小一些,Ni、Co、W为枝晶干偏析元素,其中W的偏析最为严重;共晶中富集Al、Ta、Ti、Ni,贫Co、W、Cr、Mo.凝固速率对枝晶偏析有显著的影响.随着抽拉速率的增加,元素Al、Mo、Co、Ti的偏析程度增加,而Ta的偏析程度降低,其它元素的偏析程度变化不大.     

45t LF（VD）精炼钒氮非调质钢的增氮工艺

试验和分析了成分为(%):0.42C、0.62Si、1.42Mn、0.11V、0.015N钒氮非调质钢LF(VD)吹氮精炼时合金元素、LF和VD工艺参数对该钢增氮的影响.结果表明,前期加固氮合金元素V、Cr、Mn,快速提高LF精炼温度至1 620～1 630℃,增加精炼吹氮时间,可使平均增氮速率达2.83×10-6/min;VD处理进行氮气搅拌,控制VD处理时间,可提高氮的收得率.     

新型热作模具钢的试验研究

对新型热作模具钢4Cr2Mo2MnVNbB作了全面性能试验,并与老钢种3Cr2W8V进行对比及应用考核,证明本钢种的综合性能较高,使用寿命长,可以更替3Cr2W8V钢,其应用价值显著,可供有关部门选用。     

Al-Fe-Si合金基体及强化相Al12(Fe,X)3Si价电子结构分析

基于EET理论,计算了Al-Fe-Si合金基体与强化相Al12Fe3Si,Al12(Fe,X)3Si的价电子结构,探讨了价电子结构与合金强化、合金相稳定性的关系及合金元素X对强化相稳定性的影响.结果表明:与基体α-Al相比,强化相Al12Fe3Si,Al12(Fe,X)3Si的n(A)值分别增强了248%,208%～231%,位错运动阻力分别增大2.48倍和2.08～2.31倍,从合金相价电子结构参数n(A)看,溶质原子固溶强化作用弱于析出相的强化作用;合金元素V,Cr,W,Mo,Mn的加入改变了Al12FeSi的价电子结构,使其原子状态组数σ(N)增加了2个数量级,使合金相的稳定性增强,进而延缓了粗化速度;V,Cr,W,Mo,Mn对Al12Fe3Si相稳定性影响的强弱顺序为Cr(Mn)→W(Mo)→V.     

Research on Thermal Wear of Cast Hot Forging Die Steel Modified by Rare Earths

Thermal wear of cast hot-forging die steel modified by rare earths（RE） was studied and compared with commercially used die steels. The function of RE and the mechanism of thermal wear of cast steel modified by RE were discussed. The results showed that with increasing content of RE, the wear rate of cast steel reduced at first and then increased. By adding 0.05% （mass fraction） RE, the cast hot-forging die steel with optimum thermal wear resistance was obtained, which was better than that of H13 and 3Cr2WSV. The large amount of coarse inclusions, （RE）2O2S, resulted from excessive RE, which obviously deteriorated thermal wear resistance. The mechanism of thermal wear of the modified cast die steel is oxidation wear and oxide fatigue delamination. The wear debris are lumps of Fe2O3 and Fe3O4.     

Effect of Rare Earth Elements on Quenching Crack Resistance of Steel 9Cr2Mo

Ｒｏｌｌｅｒｆｏｒｃｏｌｄｒｏｌｌｉｎｇｉｓａｋｅｙｆｏｒｇｉｎｇｐａｒｔ,ｗｈｉｃｈｅｘｐｅｒｉｅｎｃｅｓｃｏｎｔａｃｔｓｔｒｅｓｓ ,ａｌｔｅｒ ｎａｔｉｎｇｓｔｒｅｓｓａｎｄｆｒｉｃｔｉｏｎａｌｓｔｒｅｓｓｄｕｒｉｎｇｒｏｌｌｉｎｇ .Ｔｈｅｒｅｆｏｒｅ ,ｈｉｇｈｅｒｓｔｒｅｎｇｔｈ ,ｓｕｒｆａｃｅｈａｒｄｎｅｓｓ,ｗｅａｒｒｅｓｉｓｔａｎｃｅａｎｄｅｎｏｕｇｈｔｏｕｇｈ ｎｅｓｓｓｈｏｕｌｄｂｅｃｏｎｓｉｄｅｒｅｄｆｏｒｍａｎｕｆａｃｔｕｒｉｎｇｔｈｉｓｃｏｌｄｒｏｌｌｅｒ[1] .Ｓｉｎｃｅｔｈｅ…     

Effect of Rare Earth on Thermal Shock Resistance of Steel 9Cr2Mo

Ｒａｒｅｅａｒｔｈｅｌｅｍｅｎｔｓｈａｖｅｂｅｅｎａｄｄｅｄｉｎｔｏｈｏｔｒｏｌｌｅｒｓｔｅｅｌ.ＲＥｅｌｅｍｅｎｔｓｃａｎｉｍｐｒｏｖｅｔｈｅｒ ｍａｌｆａｔｉｇｕｅ[1] ,ｌｏｗｆｒｅｑｕｅｎｃｙｆａｔｉｇｕｅ[2 ] ,ｐｌａｓ ｔｉｃｉｔｙａｎｄｔｏｕｇｈｎｅｓｓ[3] ,ｒｅｆｉｎｅａｕｓｔｅｎｉｔｉｃｇｒａｉｎｓｉｚｅ[4] ａｎｄｍｏｄｉｆｙｉｎｃｌｕｓｉｏｎｓ[5 ] ｏｆｈｏｔｒｏｌｌｅｒｓｔｅｅｌ 6 0ＣｒＭｎＭｏ .Ｓｔｅｅｌ 9Ｃｒ2Ｍｏｉｓａｔｒａｄｉｔｉｏｎａｌｃｏｌｄｒｏｌｌｅｒｓｔｅｅｌ.Ｗｈｅｎ…     

丝锥用Nb微合金化TGM2A-S高速钢的开发

TGM2A-S钢(/%:0.85C、0.27Si、0.24Mn、0.026P、0.007S、3.98Cr、4.76Mo、6.09W、1.83V、0.12Nb、0.03RE)是在高速钢TGM2A的基础上添加微量铌和稀土开发的新型丝锥用高速钢。TGM2A-S钢的生产工艺流程为25 t EAF-30 t LF-VD(微合金化)-铸锭(700 kg)二火锻造(85 mm方)-连轧(Φ8 mm)-冷拉(Φ6.6 mm)-加工丝锥(M6)。结果表明,原工艺:3 t中频感应炉-ESR (280 kg锭)-二火锻造(85 mm方)-连轧(Φ8 mm)-冷拉(Φ6.6 mm)-加工丝锥(M6)生产的TGM2A钢中的O和N含量分别为35.4×10^-6和123.6×10^-6,而改进工艺生产的TGM2A-S钢的O和N含量分别为15.7×10^-6和87.7×10^-6。TGM2A-S钢的丝锥切削寿命较电渣工艺生产的TGM2A钢提高20%; TGM2A-S钢的淬火晶粒为10.5级,电渣工艺生产的TGM2A钢的晶粒度为10级。     

稀土元素在洁净重轨钢中存在状态的热力学模型研究

建立了可以定量描述洁净稀土重轨钢凝固过程中成分偏析与夹杂物析出的耦合热力学模型,经文献验证,模型具有较高精度。通过模型分析了稀土加入量对洁净钢中夹杂物的析出规律与稀土存在状态的影响。得出在洁净重轨钢中加入稀土可以变质钢中MnS、Al₂O₃夹杂;钢中首先析出稀土氧硫化物(或稀土铝酸盐),其次是稀土硫化物,最后是稀土氮化物;在同一稀土加入量条件下,固溶La的量要大于固溶Ce的量。     

Effects of Rare Earth Elements on Corrosive Wear Behaviour of Cast Cr-Mn-N Stainless Steel in Dilute Sulphuric Acid

ＥｆｅｃｔｓｏｆＲａｒｅＥａｒｔｈＥｌｅｍｅｎｔｓｏｎＣｏｒｒｏｓｉｖｅＷｅａｒＢｅｈａｖｉｏｕｒｏｆＣａｓｔＣｒＭｎＮＳｔａｉｎｌｅｓＳｔｅｌｉｎＤｉｌｕｔｅＳｕｌｐｈｕｒｉｃＡｃｉｄＤｉｎｇＨｕｉ（丁晖），ＹｕａｎＧｕａｎｇｙｉｎ（袁广银），...     

稀土对V微合金重轨钢高温塑性的影响

U76CrRE钢(/%:0.71～0.80C、0.50～0.80Si、0.80～1.10Mn、0.04～0.10V、0.25～0.35Cr、0.02RE)和U75V钢(/%:0.70～0.78C、0.50～0.70Si、0.75～1.05Mn、0.04～0.08V)的冶炼工艺流程为铁水预处理-150 t复吹转炉-LF-VD 280 mm×380 mm连铸,LF精炼后通过喂稀土包芯线加入稀土。对钢的铸坯进行热塑性试验结果表明,加入稀土主要在第Ⅲ脆性区提高V微合金重轨钢的高温塑性,950～1225℃U76CrRE钢和U75V钢的平均断面收缩率Z值分别为83.34%和65.17%,1250℃U76CrRE钢和U75V钢的Z值分别为58%和12%。为防止铸坯出现裂纹,铸坯的矫直温度应≥900℃。     

Formation of intermetallic compound at interface between rare earth elements and ferritic-martensitic steel by fuel cladding chemical interaction

The intermetallic compounds formation at interface between rare earth elements and clad material were investigated to demonstrate the effects of rare earth elements on fuel-cladding chemical interaction(FCCI)behavior.Mischmetal(70Ce-30La)and Nd were prepared as rare earth elements.Diffusion couple testing was performed on the rare earth elements and cladding(9Cr2W steel)near the operation temperature of(sodium-cooled fast reactor)SFR fuel.The performance of a diffusion barrier consisting of Zr and V metallic foil against the rare earth elements was also evaluated.Our results showed that Ce and Nd in the rare earth elements and Fe in the clad material interdiffused and reacted to form intermetallic species according to the parabolic rate law,describing the migration of the rare earth element.The diffusion of Fe limited the reaction progress such that the entire process was governed by the cubic rate law.Rare earth materials could be used as a surrogate for high burnup metallic fuels,and the performance of the barrier material was demonstrated to be effective.     

不锈钢连铸板坯结晶器钢液喂稀土丝工艺试验研究

通过工业试验并结合数值模拟计算,研究了不锈钢连铸结晶器钢液喂稀土丝工艺的铸坯稀土收得率和稀土元素分布。结果表明,结晶器喂稀土丝其稀土收得率高达85%,但实际铸坯外层靠近凝固坯壳处稀土含量相对较高且分布不均匀(RE 0.059%～0.073%),其原因是由于结晶器钢液凝固早期稀土浓度偏高而且分布不均匀。因此,在模拟计算或实际生产中,应考虑凝固相变对稀土分布的影响,并注意稀土丝直径、喂线速度与连铸参数的匹配,避免稀土元素的偏聚。     

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.