Semisolid Slurry Preparation of Die Steel with High Chromium Content

The semisolid slurry preparation of die steels Cr12 and Cr12MoV with high chromium content was studied. The results show that the semisolid slurry of both steels with solid of 40%-60% can be made by electromagnetic stirring method and is easy to be discharged from the bottom little hole of the stirring chamber. The sizes of the spherical primary austenite in the slurry of die steels Cr12 and Cr2MoV are 50-100 μm and 80-150μm, respectively. The homogeneous temperature field and solute field for both steel melts are obtained. The strong temperature fluctuation in the melt with many fine primary austenite grains occurs and the remelting of the secondary arm roots at the same time is accelerated because of the electromagnetic stirring. These are the most important reasons for deposition of spherical primary austenite grains.     

氮对304奥氏体不锈钢组织和力学性能的影响

在０Ｃｒ１８Ｎｉ９奥氏体不锈钢成分基础上，加入一定的氮，并使钢中的镍含量控制在标准下限含量的条件下，研究了氮对组织和力学性能的影响。结果表明：加氮后钢的强度提高，奥氏体稳定不变，固溶态组织不变，而敏化后晶界析出物类型有所不同。     

1Cr18Ni9Ti铁素体和探伤超标的解决途径

1Cr18Ni9Ti不锈钢是奥氏体不锈钢,本文主要阐述通过控制温度和变形量在热加工中的应用,来解决其在热加工中易出现的两个问题:铁素体超标和探伤粗晶。     

聚氯乙烯脱氯反应器不锈钢内衬抗腐蚀的研究

聚氯乙烯(PVC)在脱氯过程中会产生大量的HCl气体,而HCl具有很强的腐蚀性.对3种奥氏体不锈钢(00Cr17Ni14Mo3(316L)、0Cr18Ni9Ti(321)、1Cr18Ni9(302))进行抗HCl气体腐蚀实验,并对试样进行扫描电镜(SEM)和能谱(EDS)分析.结果表明:不锈钢316L的抗HCl气体的腐蚀性能最好,在本研究条件下,不锈钢316L最适合用来作PVC脱氯反应器的内衬.     

A New Pb-free Machinable Austenitic Stainless Steel

 In the present paper, the machinability tests were conducted by using various processing parameters on a CA6164 lathe with a dynamometer. The metallurgical properties, machinability and mechanical properties of the developed alloy were compared with those of an austenite stainless steel 1Cr-18Ni-9Ti. The results have shown that the machinability of the austenitic stainless steels with free-cutting additives is much better than that of 1Cr-18Ni-9Ti. This is attributed to the present of machinable additives. The inclusions might be composed of MnS. Sulfur and copper addition contributes to the improvement of the machinability of austenitic stainless steel. Bismuth is an important factor to improve the machinability of austenitic stainless steel, and it has a distinct advantage over lead. The mechanical properties of the free cutting austenitic stainless steel are similar to that of 1Cr-18Ni-9Ti. A new Pb-free austenitic stainless steel with high machinability as well as satisfactory mechanical properties has been developed.     

八角梅花形内圆不锈钢管试制

八角梅花形内圆不锈钢管为食品行业专用异型管材,该产品原用铜合金管再内外涂金,产品加工工艺复杂,价格昂贵,且由于产品频繁使用造成色彩不均及剥落带来对人体的危害,故国外发达国家现选用奥氏体不锈钢,即1Cr18Ni9Ti或1Cr18Ni9材料作为替代品。而奥氏不锈钢异型管比铜合金管具有更好的抗蚀性,耐磨性,价格低廉等特点。     

α-相对2.625 t1Cr18Ni9Ti 不锈钢锭初轧坯表面质量的影响

生产实践表明,1Cr18Ni9Ti奥氏体不锈钢α-相数量(级别)是影响2．625 t钢锭初轧坯表面质量的主要因素,当钢中α-相超过2．5级[α-相含量(面积)=12％]时,钢坯表面质量急剧下降。当钢中C为0．08％(Cr+ 3．28Ti) ／Ni≤2,钢锭均热温度≤1 270℃时,钢中α-相≤2．5级,可得到良好表面质量的轧坯。为获得较好的轧坯表面质量,应控制钢中Ti≤0．70％、电渣母材的Ti≤0．80％。     

15Ni?15Cr ODS钢的微观结构与力学性能

氧化物弥散强化（Oxide dispersion strengthened, ODS）钢因其良好的高温力学性能和抗辐照性能被认为是钠冷快堆包壳材料的重要候选材料. 本文通过机械合金化以及热等静压和锻造工艺制备了15Ni?15Cr ODS奥氏体钢,并且采用相同工艺制备了不加氧化物的15Ni?15Cr奥氏体钢作为参比材料. 利用透射电镜对样品的微观结构进行分析,发现15Ni?15Cr和15Ni?15Cr ODS奥氏体钢晶粒尺寸分别为0.75和0.5 μm. 15Ni?15Cr ODS奥氏体钢中分布的氧化物弥散粒子主要为δ-Y₄Zr₃O₁₂以及少量的Al₂O₃. 15Ni?15Cr ODS奥氏体钢中氧化物弥散粒子的平均粒径为12.8 nm、数密度5.5×1022 m?3、粒子间距26 nm. 相比于15Ni?15Cr奥氏体钢,15Ni?15Cr ODS奥氏体钢具有更高的强度,但是高温塑性有所降低. 15Ni?15Cr ODS奥氏体钢的室温断裂机制为韧性断裂,高温断裂机制为韧–脆混合断裂.      

Cavitation Erosion Behavior and Mechanism of HVOF Sprayed WC-10Co-4Cr Coating in 3.5 wt% NaCl Solution

A WC-10Co-4Cr coating was prepared by high-velocity oxygen-fuel (HVOF) thermal spraying process. The cavitation erosion (CE) characteristics of the coating as well as the stainless steel 1Cr18Ni9Ti were investigated in 3.5 wt% NaCl solution. The coating exhibited higher CE resistance than that of the stainless steel 1Cr18Ni9Ti. After being eroded for 20 h, the CE volume loss of the stainless steel 1Cr18Ni9Ti is 3.22 times to that of the coating. The removal mechanism for the coating was erosion of the binder phase first, followed by brittle detachment of hard phases as a result of the action of corrosion and mechanical effect. The cracks were found to initiate at the carbide-binder interface and the edge of the pores, leading to craters on the surface and accelerating the damage of the coating. Fatigue and plastic deformation were found to be the material removal mechanism for the substrate steel 1Cr18Ni9Ti.     

TTS443高铬铁素体不锈钢的开发

针对304(Crl8-Ni8型)奥氏体不锈钢和430(Cr17型)铁素体不锈钢的特性,通过试验和分析Cr、Cu、Nb、Ti等合金元素对铁基合金材料性能的影响,开发出一种高铬铁素体不锈钢-TTS443(/%:O.010C、21Cr、0.40Cu、0.25Nb、0.20Ti、O.012N) 。该钢种的耐蚀性能与304奥氏体不锈钢相当,具有良好的成形性与焊接性能,TTS443铁素体不锈钢是304奥氏体不锈钢理想代替材料。     

电磁搅拌对半固态钢铁组织的影响

研究电磁搅拌对半固态铸铁初生奥氏体和弹簧钢铸态组织的作用.研究表明:铸铁在凝固过程中,经过短时间的电磁搅拌,粗大的初生奥氏体枝晶就可以被破碎细化,而且随着搅拌功率的加大,初生奥氏体更加球状化或非枝晶化;经过电磁搅拌,引起铸铁熔体的强烈流动和温度起伏,加速了初生奥氏体枝晶二次臂的熔断和一次臂的缩短,最终使树枝状初生奥氏体转变为球状的初生奥氏体.研究还表明:电磁搅拌可以明显细化弹簧钢的柱状枝晶,代之以细等轴晶.     

06Cr19Ni10奥氏体不锈钢的DTA试验与组织分析

 根据铬当量、镍当量的计算结果推断了06Cr19Ni10奥氏体不锈钢的凝固模式,并采用差热分析技术（DTA）对06Cr19Ni10奥氏体不锈钢在10和30℃/min的加热冷却速度下的凝固过程进行了研究,对DTA曲线中的吸热峰和放热峰进行了分析,并采用激光共聚焦显微镜（LSCM）和扫描电子显微镜（SEM）对样品进行了测定。分析结果表明：06Cr19Ni10奥氏体不锈钢的实际凝固模式为FA型,即铁素体奥氏体型。随着冷却速率的增加,奥氏体形核率增大,残余的δ铁素体在形态上更加细小分散。该研究结果对实际生产中改善铸坯组织,提高铸坯质量具有着一定的意义。     

钛含量对0Cr13Co8Ni5Mo马氏体时效不锈钢冲击韧性的影响

 通过具有不同Ti含量的三炉试验钢,研究了Ti含量对0Cr13Co9Ni5Mo 马氏体时效不锈钢的力学性能、金相组织和奥氏体含量的影响。研究结果表明：添加较多的Ti可显著降低基体组织中的有效C、N含量,大幅降低固溶、时效处理后残余/逆转变奥氏体含量,最终使冷脆转化温度显著上升,在提高强度的同时降低了钢的韧性。     

CeO2对不锈钢基SiO2-BaO-Al2O3-Cr2O3陶瓷涂层性能的影响

采用高温熔烧法于1Cr18Ni9Ti不锈钢基材表面制备掺CeO2的SiO2-BaO-Al2O3-Cr2O3陶瓷涂层,研究了不同含量CeO2对涂层的抗氧化性、抗热震性和硬度的影响。研究结果表明,含CeO2的不锈钢基SiO2-BaO-Al2O3-Cr2O3陶瓷涂层能有效阻止不锈钢基体的氧化增重,提高涂层的抗热震性能及硬度。本实验条件下,CeO2含量2.8%时,涂层具有最好的抗氧化性能和抗热震性能。     

等离子熔覆镍基合金的组织及其冲蚀磨损性能

为提高不锈钢材料的耐冲蚀磨损性能,以Ni46合金粉末为原料,采用等离子熔覆工艺在不锈钢1Cr18Ni9Ti基材上制备镍基合金涂层,分析了熔覆层的显微组织以及物相形貌和相结构等,测定了涂层的显微硬度.使用旋转圆盘实验机研究了Ni基等离子熔覆合金涂层在砂浆中的冲蚀行为.结果表明:材料的冲蚀磨损性能受到材料基本力学性能的限制,高硬度镍基涂层的抗冲蚀性能最好,在相同实验条件下其磨损率由小到大排列顺序为镍基涂层>0Cr13Ni5Mo>1Cr18Ni9Ti;镍合金层中奥氏体基体的固溶强化和硬质相有效抵御砂砾的冲击,是Ni基等离子熔覆合金层具有高抗冲蚀性能的主要原因.     

MA956 ODS合金微晶涂层对1Cr18Ni9Ti不锈钢氧化性能的改善

采用高频电脉冲沉积技术在1Cr18Ni9Ti不锈钢表面上沉积了厚度约为50μm的MA956 ODS合金纳米微晶涂层、涂层与基体之间呈现良好的冶金结合.在1000℃静态空气中对1Cr18Ni9Ti试样与表面施加涂层试样进行了总计100h的恒温氧化实验.用AFM,SEM,EDX和XRD分别对涂层和氧化后试样的形貌。成分和组成进行了观察和分析.结果显示:1Cr18Ni9Ti表面沉积MA956ODS。合金纳米微晶涂层促进了Cr的选择氧化,提高了1Cr18Ni9Ti表面氧化膜的粘附性,改善了1Cr18Ni9Ti抗高温氧化性能.     

Investigation on Metallurgical Factors Controlling Charpy Impact Toughness in 1Cr21Ni5Ti Duplex Stainless Steel

 Based on the fact that toughness degradation occurred in 1Cr21Ni5Ti duplex stainless steel during slow cooling in a temperature interval of 400-600 ℃ following brazed welding, a simulated embrittlement treatment was utilized to evaluate its embrittlement tendency. Accumulated experiences have shown that high Ti and Al contents led frequently to severe toughness deterioration. To elucidate this phenomenon, four heats with various Ti and Al contents were prepared in laboratory scale melts, which were used to investigate the inherent embrittlement nature. The results have shown that 550 ℃ aging led only to a modest toughness reduction, whereas, aging around 475 ℃ resulted in ferrite embrittlement, regardless of Ti, Al levels. However, high Ti, Al levels reduced the austenite phase, which, in the case of its inferior shape and distribution due to insufficient hot deformation, failed to resist cleavage type cracks initiated in the ferrite phase. Increasing hot forged areas reduction could modify the shape and distribution of austenite, resulting in the enhanced resistance of the austenite to the cleavage type cracks, which have been confirmed to be beneficial for brittlement suppression of 1Cr21Ni5Ti duplex stainless steel.     

倾斜板法制备9Cr18半固态坯料二次重熔的微观组织演变

研究利用倾斜板法制备的9Cr18半固态坯料在二次重熔过程中微观组织演变,以期对后续触变成形提供必要的理论基础。研究结果表明,采用倾斜板浇注法可以得到优质的9Cr18半固态坯料,其典型组织为初生固相奥氏体（γ₁）球状晶粒和晶界网状组织构成,网状组织为二次奥氏体（γ₂）和M₇C₃碳化物液相共晶组织。球状晶粒的平均直径为93.5 μm,形状因子0.69,半固态坯料球状晶粒边界光滑,大小相对均匀。固液两相中Fe、C、Cr存在着明显的元素差异。液相组织中Cr、C元素富集,固相中Fe含量较高。采用波浪形倾斜板法制备的9Cr18合金半固态坯料重熔组织形貌优于传统铸锭重熔组织。半固态坯料重熔后的组织化学成分更为均匀,晶粒也更圆整,固液界面平滑,且加热温度越高,晶粒越圆整,液相率越高。二次重熔后碳化物尺寸明显减小,平均宽度仅为0.5 μm,长度大大减小使得其形态接近粒状。      

纳米镀镍层作中间层的钛合金与不锈钢扩散焊接

采用电镀纳米镍中间层,对钛合金TA17与不锈钢0Cr18Ni9Ti进行扩散焊焊接试验研究.利用能谱对焊接接头的元素分布进行分析,结果表明:采用电镀纳米镍层作中间层能有效防止钛合金中的Ti、V、Al等元素与不锈钢中Fe、Ni、C等元素的相互扩散和迁移,很好地抑制了金属间化合物TiFe、TiFe2及脆性相TiC的形成.通过计算接头处扩散层的激活能可知纳米镍的扩散性能比镍箔的好.