双金属复合锤头的研制及生产

分别采用高铬铸铁和碳素钢作为锤端和锤柄.造型时锤端和浇注系统内浇道的成型分别采用消失模模型.复合时将砂型整体放入感应线圈中感应加热,加热过程中消失模受热汽化.当锤柄升到预定温度（800℃左右）时,开始浇注复合层金属液.所得的界面为完全冶金结合.复合部分经热处理后组织为Cr7C3共晶碳化物＋马氏体＋少量残奥,HRC≥58,ak≥12 J/cm^2.锤头使用寿命是同等工况下高锰钢的5倍左右.     

镶铸式复合锤头的铸造工艺研究

分别采用高铬铸铁和碳素钢作为锤端和锤柄.造型时将涂附保护剂的锤柄套上锤端整体放入砂型中,锤端和浇道采用消失模.采用立浇的方式,锤端设置冒口.复合时将砂型整体放入感应线圈中感应加热,锤柄升到一定温度时,开始浇注金属液并继续加热,待金属液完全覆盖锤柄时停止加热,继续浇注直到充满整个冒口.所得的界面为完全冶金结合.复合层经热处理组织为Cr7C3共晶碳化物 马氏体 少量残奥,硬度≥58 HRC,冲击韧度≥12 J/cm2.锤头使用寿命是同等工况下高锰钢的4倍左右.     

双金属复合锤头的研制及生产

分别采用高铬铸铁和碳素钢作为锤端和锤柄。造型时锤端和浇注系统内浇道的成型分别采用消失模模型。复合时将砂型整体放入感应线圈中感应加热,加热过程中消失模受热汽化。当锤柄升到预定温度(800℃左右)时,开始浇注复合层金属液。所得的界面为完全冶金结合。复合部分经热处理后组织为Cr7C3共晶碳化物+马氏体+少量残奥,HRC≥58,ak≥12 J／cm2。锤头使用寿命是同等工况下高锰钢的5倍左右。     

高铬铸铁堆焊锤柄双金属复合锤头的开发研究

为了提高双金属复合锤头锤柄的耐磨性和复合界面的结合强度,本文采用先对锤柄堆焊一层高铬铸铁耐磨材料,然后再采用型内感应加热进行镶铸的工艺.得到的近共晶成分的高铬铸铁表面堆焊层,在低预热温度下与锤端接触部分达到良好的冶金结合,锤柄堆焊层耐磨性较未堆焊前提高了20倍,改善了工作环境,锤头整体寿命提高了一倍多.     

服务园地·问答与讨论信箱

48如何用消失模铸造工艺生产高铬铸铁双金属复合锤头?锤头为高铬铸铁,锤柄为2G35(2G40)和2GMn13或结构钢Q235机械加工而成.解答一:用消失模铸造生产此类复合锤头,有镶铸式和复铸式 2种工艺.(1)锤头,锤柄镶铸式锤头为高铬铸铁或铬系白口口铸铁,可用砂型,金属型、V法、消失模法等工艺预先浇铸各种型式锤头(质量、大小,形状等);锤柄除用铸造锤头的工艺浇注外,也可用机械加工方法制作,如用结构钢(型材、板材、棒材、扁钢等)加工而制得.     

型内感应加热双金属复合磨辊的研制

双金属复合磨辊复合层采用高铬铸铁,基体辊芯采用碳素结构钢.采用型内感应加热工艺进行复合.造型时辊芯预先放置在砂型中,复合时将包含有辊芯的砂型整体放入到感应圈内采用中频感应原理对辊芯进行预热,达到预定温度后浇注并继续进行加热,复合层将基体辊芯包覆后停止加热并继续浇注,使金属液充满冒口.所得到的双金属复合磨辊结合界面为完全冶金结合.经过热处理后,复合层组织为断续分布的Cr7C3共晶碳化物 马氏体 少量残余奥氏体,基体组织为珠光体 铁素体.应用于破碎粉磨石灰石和钛铁矿的结果表明,双金属复合磨辊使用寿命是高锰钢磨辊的3倍左右.     

高铬铸铁-铸钢双金属复合锤头的研制

介绍了采用镶铸复合铸造工艺生产破碎用高铬铸铁-铸钢双金属复合锤头的材质选取,组织性能及生产工艺.锤端采用高铬铸铁,化学成分如下C25%;Cr18%,锤柄采用碳钢材质,锤端与锤柄间采用冶金结合和机械结合双重结合工艺.所生产的锤头锤端硬度高(HRC＞56),锤柄韧性好,两者结合良好,使用安全可靠,与高猛钢锤头相比,使用寿命提高4倍左右.     

高铬铸件——铸钢双金属复合锤头的研制

介绍了采用镶铸复合铸造工艺生产破碎用高铬铸铁－－铸钢双金属复合锤头的材质选取,组织性能及生产工艺。锤端采用高铬铸铁,化学成分如下：Ｃ：２．５％;Ｃｒ：１８％,锤柄采用碳钢材质,锤端与锤柄间采用冶金结合和机械结合双重结合工艺。所生产的锤头锤端硬度高（ＨＲＣ〉５６）,锤柄韧性好,两者结 合良好,使用安全可靠,与高猛钢锤头相比,使用寿命提高４倍左右。     

感应加热钢／铝双金属界面的研究

双金属复合铸件外层采用铸造铝合金,内层选取碳素结构铜,采用型内感应加热工艺进行复合。造型时内层钢套预先放置在砂型中,复合时将包含有钢套的砂型整体放入到感应圈内采用中频感应原理对钢套进行预热,达到预定温度后浇注并继续进行加热,复合层将基体钢套包覆后停止加热。所得到的双金属复合铸件结合界面为完全冶金结合。复合层组织为连续分布FeAl3与Fe2Al5中间化合物。界面结合强度为76．4MPa。     

型内感应加热铝-钢双金属复合界面的研究

双金属复合铸件外圈采用铸造铝合金，内圈选取碳素结构钢，采用型内感应加热工艺进行复合。造型时内层钢套预先放置在砂型中，复合时将包含有钢套的砂型整体放人到感应圈内采用中频感应原理对钢套进行预热，达到预定温度后浇注并继续进行加热，复合层将基体钢套包覆后停止加热。所得到的双金属复合铸件结合界面为完全冶金结合，复合层组织为连续分布FeAl3与Fe2Al5中间化合物，界面结合强度为76．4MPa。     

Effects of Post-weld Heat Treatment on Microstructure,Mechanical Properties and the Role of Weld Reinforcement in 2219 Aluminum Alloy TIG-Welded Joints

In as-welded state, each region of 2219 aluminum alloy TIG-welded joint shows diff erent microstructure and microhardness due to the diff erent welding heat cycles and the resulting evolution of second phases. After the post-weld heat treatment, both the amount and the size of the eutectic structure or θ phases decreased. Correspondingly, both the Cu content in α-Al matrix and the microhardness increased to a similar level in each region of the joint, and the tensile strength of the entire joint was greatly improved. Post-weld heat treatment played the role of solid solution strengthening and aging strengthening. After the post-weld heat treatment, the weld performance became similar to other regions, but weld reinforcements lost their reinforcing eff ect on the weld and their existence was more of an adverse eff ect. The joint without weld reinforcements after the post-weld heat treatment had the optimal tensile properties, and the specimens randomly crack in the weld zone.     

The First Phase of the SRIF Industrialized Base in ＂West Area＂ Has Been Put into Operation

After nearly two years＇ tense construction, the first phase of industrialized base of Shenyang Research Institute of Foundry （SRIF）, located at the Tiexi Casting and Forging Industrial Park in the west of Tiexi District, has now been completed and formally put into operation.     

新型的治疗阿尔茨海默氏症药物(1-二甲基磷酰基-2,2,2-三氯)-乙基-1-醇烟酸醋对体外神经细胞的作用

目的: 观察本实验室合成的一种治疗阿尔茨海默氏症(AD)的药物(1-二甲基磷酰基-2, 2, 2 -三氯)-乙基^-1-醇烟酸醋(NMF),对体外培养的皮层神经细胞活性的影响以及对海人藻酸(KA)所致的神经损伤的保护作用。方法: 采用体外培养皮层神经元的方法,解剖分离 15 d胚胎小鼠皮层神经细胞, 接种于 96孔板,48 h 后加药并培养 72 h,以 MIT 法 观察 NMF 对小鼠皮层神经细胞活性的影响;同时将接种于 24 孔板的细胞预先给予 NMF,d 3 时加或不加KA处理后,以台盼蓝染色鉴别并计数死、活细胞,可得出细胞的存活率。结果: NMF 明显促进胎鼠皮层神经元活性,其中 NMF1、0. 1、10nmol·L^-1促进神经元活性增殖率分别高达 34.7%、37.4%、36. 7%, NMF 明显促进正常胎鼠皮层神经元存活卒,与对照组比较,10nmol·L^-1 NMF 对皮层神经元的存活率分别提高 39.3%、73.5%。 NMF能显著 对抗 KA 所致的神经元损伤,与 KA 损伤组相比, NMF0.1、10、10nmol·L^-1对损伤皮层神经元的保护率分别为 77.30%、80.10%、84.15%。结论: NMF 明 显促进胎鼠皮层神经元的洁性、提高正常皮层神经元,的存活卒,并能有效地保护KA所致的神经元损伤,提示 NMF 是一种很有潜力的治疗 AD 的药物。     

Three-Dimensional Growth of Coherent Ferrite in Austenite: A Molecular Dynamics Study

Coherent second phase often exhibits anisotropic morphology with specifi c orientations with respect to both the second and the matrix phases. As a key feature of microstructure, the morphology of the coherent particles is essential for understanding the second-phase strengthening eff ect in various industrial alloys. This letter reports anisotropic growth of coherent ferrite from austenite matrix in pure iron based on molecular dynamics simulation. We found that the ferrite grain tends to grow into an elongated plate-like shape, independent of its initial confi guration. The fi nal shape of the ferrite is closely related to the misfi t between the two phases, with the longest direction and the broad facet of the plate being, respectively, consistent with the best matching direction and the best matching plane calculated via the Burgers vector content(BVC) method. The strain energy calculation in the framework of Eshelby's inclusion theory verifi es that the simulated orientation of the coherent ferrite is energetically favorable. It is anticipated that the BVC method will be applicable in analysis of anisotropic growth and morphology of coherent second phase in other phase transformation systems.     

Effect of Rare Earth Doping on Impedance,Modulus and Conductivity Properties of Multiferroic Composites:0.5(BiLa_xFe_(1-x)O_3)–0.5(PbTiO_3)

The Lanthanum-doped bismuth ferrite–lead titanate compositions of 0.5(Bi LaxFe1-xO3)–0.5(Pb Ti O3)(x = 0.05,0.10,0.15,0.20)(BLxF1-x-PT) were prepared by mixed oxide method.Structural characterization was performed by X-ray diffraction and shows a tetragonal structure at room temperature.The lattice parameter c/a ratio decreases with increasing of La(x = 0.05–0.20) concentration of the composites.The effect of charge carrier/ion hopping mechanism,conductivity,relaxation process and impedance parameters was studied using an impedance analyzer in a wide frequency range(102–106Hz) at different temperatures.The nature of Nyquist plot confirms the presence of bulk effects only,and non-Debye type of relaxation processes occurs in the composites.The electrical modulus exhibits an important role of the hopping mechanism in the electrical transport process of the materials.The ac conductivity and dc conductivity of the materials were studied,and the activation energy found to be 0.81,0.77,0.76 and 0.74 e V for all compositions of x = 0.05–0.20 at different temperatures(200–300 °C).     

Quantitative Analysis of the Crystallographic Orientation Relationship Between the Martensite and Austenite in Quenching–Partitioning–Tempering Steels

The orientation relationships(ORs)between the martensite and the retained austenite in low-and medium-carbon steels after quenching–partitioning–tempering process were studied in this work.The ORs in the studied steels are identified by selected-area electron diffraction(SAED)as either K–S or N–W ORs.Meanwhile,the ORs were also studied based on numerical fitting of electron backscatter diffraction data method suggested by Miyamoto.The simulated K–S and N–W ORs in the low-index directions generally do not well coincide with the experimental pole figure,which may be attributed to both the orientation spread from the ideal variant orientations and high symmetry of the low-index directions.However,the simulated results coincide well with experimental pole figures in the high-index directions{123}_(bcc).A modified method with simplicity based on Miyamoto’s work was proposed.The results indicate that the ORs determined by modified method are similar to those determined by Miyamoto’method,that is,the OR is near K–S OR for the low-carbon Q–P–T steel,and with the increase of carbon content,the OR is closer to N–W OR in medium-carbon Q–P–T steel.     

Effect of Short-Time Aging on the Pitting Corrosion Behavior of a Novel Lean Duplex Stainless Steel 2002

The effect of short-time aging in the temperature range between 400 and 1000 °C on the pitting corrosion behavior and mechanical property of a novel lean duplex stainless steel(LDSS) 2002 was investigated through the potentiostatic critical pitting temperature(CPT) tests and the Charpy impact tests. Both the pitting corrosion resistance and the toughness of aged specimens degraded due to the precipitation of detrimental secondary phases and the most significant reduction of CPT and impact energy emerged at 650 °C concurrently. The CPT of LDSS 2002 specimen aged at 650 °C decreased by 28 °C, and the impact energy dropped from 69 to 29 J/cm~2 compared with the solution-annealed sample. Transmission electron microscopy characterization showed that the main precipitates in LDSS 2002 were Cr_2N and M_(23)C_6 along the ferrite–austenite grain boundaries.     

Information for Contributors

正The Transactions of Nonferrous Metals Society of China,founded in 1991 and sponsored by The Nonferrous Metals Society of China,is published monthly now and mainly contains reports of original research which reflect the new progresses in the field of nonferrous metals science and technology,including mineral processing,extraction metallurgy,metallic materials and heat treatments,metal working,physical metallurgy,powder metallurgy,with the emphasis     

Preface

<正>We are pleased to present this Special Issue of Transactions of Nonferrous Metals Society of China containing selected papers from the First Asian Conference on Aluminum Alloys(ACAA-2013),held in Beijing,China,13–17 October 2013.This conference has been initiated,with approval of     

Information for Contributors

The Transactions of Nonferrous Metals Society of China, founded in 1991 and sponsored by The Nonferrous Metals Society of China, is published monthly now and mainly contains reports of original research which reflect the new progresses in the field of nonferrous metals science and technology, including mineral processing, extraction metallurgy, metallic materials and heat treatments, metal working, physical metallurgy, powder metallurgy, with the emphasis on fundamental science. It is the unique preeminent publication in English for scientists, engineers, under/post-graduates on the field of nonferrous metals industry. This journal is covered by many famous abstract/index systems and databases such as SCI Expanded, Ei Compendex Plus, 1NSPEC, CA, METADEX, AJ and JICST.