SPV490钢轧后在线热处理工艺研究

研究了SPV490钢控轧后在线直接淬火、回火工艺参数与其力学性能之间的关系。分析了不同的工艺参数对钢板组织及性能的影响。结果表明：经奥氏体再结晶区和未再结晶区两阶段结合控制轧制后在线930℃直接淬火、640℃回火，钢板可获得均匀、细小的回火索氏体组织，其综合力学性能均超过标准要求。     

低合金高强钢在线冷却工艺研究

研究了超快冷工艺参数对低合金调质高强钢的组织性能的影响规律.实验钢在轧后空冷以及快速冷却至520℃左右时,均得到粒状贝氏体组织,粗大的M/A岛降低了冲击韧性.快冷至210℃以下时得到全部的板条马氏体组织,达到了直接淬火的目的.实验结果表明,采用在线直接淬火回火工艺时钢板的综合力学性能优于离线淬火工艺,表明超快冷条件下在线热处理技术在发展减量化高性能钢中具有优势.     

回火工艺对在线淬火12MnNiVR钢组织和性能的影响

利用SEM、TEM等分析方法及性能检测研究了回火工艺参数对在线淬火12MnNiVR钢组织及性能的影响。结果表明,在线淬火后的12MnNiVR钢板淬火组织为淬火马氏体加少量淬火贝氏体的复合组织;经(625～655)℃×60min回火可以获得均匀的回火贝氏体组织,其综合力学性能均超过要求。抗拉强度可达到628MPa以上,屈服强度可达562MPa以上,伸长率达21%以上,-20℃冲击功达到220J以上。     

不同工艺对低碳钢钢板力学性能及屈强比的影响

本文研究了一种C-Mn-Nb-V成分体系低碳钢钢板在不同工艺条件下的力学性能。对比了TMCP控轧控冷,在线、离线淬火,亚温淬火工艺条件下钢板的力学性能及回火处理前后钢板屈强比。采用“TMCP+回火”工艺,钢板屈强比为0. 89;采用“在线、离线淬火+回火”工艺,钢板屈强比升至0. 92及以上;采用“亚温淬火+回火”工艺,得到了回火马氏体+亚临界铁素体的混合组织,钢板屈强比仅为0. 75。研究结果表明,采用“亚温淬火+回火”工艺,钢板综合力学性能良好且具有较低的屈强比。     

热处理工艺对NM400低合金钢板组织性能的影响

研究了在线淬火-缓冷-回火工艺对NM400低合金钢板组织性能的影响,并与同等工艺条件下离线热处理后实验钢板的显微组织和力学性能进行了比较。结果表明：在线淬火-缓冷-回火工艺处理的钢板可获得大量压扁拉长的板条马氏体、铁碳化合物和少量的残余奥氏体组织,而离线热处理的钢板则获得较为规则的板条马氏体组织。在线淬火-缓冷-回火处理工艺可提高耐磨钢板的屈服强度和塑性,而离线热处理耐磨钢板的冲击韧性和抗拉强度较好。     

低屈强比超高强EH690钢板的研发

采用常规化学成分、轧制和调质热处理工艺生产的超高强EH690钢板屈强比在0.96以上,为了实现钢板较低的屈强比,一般采用低碳、高合金的化学成分设计,然后再进行两次淬火(常温淬火Q+两相区淬火Q＇)+回火的工艺,生产工艺复杂,生产成本较高。为此,采用低合金化学成分设计,合理的控轧控冷工艺及亚温淬火+回火的热处理工艺,研究了不同亚温淬火温度、回火温度对EH690钢板力学性能和显微组织的影响。结果表明:所设计化学成分的EH690钢板经过815 ℃的亚温淬火+480 ℃回火热处理后,钢板具有合适比例的软相铁素体和硬相马氏体双相组织,这种组织在保证钢板具有较好力学性能的同时屈强比也降低到0.90左右。采用该工艺,简化了生产工艺流程,降低了生产成本,实现了低屈强比超高强EH690钢板的工业化大规模生产。     

在线淬火后回火工艺对塑料模具钢组织和性能影响

研究不同回火工艺参数对在线淬火生产的3Cr2Mn Ni Mo塑料模具钢板组织性能及硬度的影响。利用光学显微镜及硬度仪分析了试样的显微组织及硬度。结果表明:试样在线淬火后回火温度越高,硬度越低;600℃回火1 h到2 h时,硬度下降比较快,回火2 h到8 h时,硬度下降呈线性趋势。回火时间在2 h内时,回火时间对硬度的影响程度要大;采用在线淬火方式冷却钢板硬度可以达到约为46~48 HRC时,应采用630℃回火4 h可以得到28~36 HRC的回火硬度;采用在线淬火冷却钢板硬度达到约为43~46 HRC时,应采用610℃回火4 h可以得到28~36 HRC的回火硬度。     

热处理工艺对HB400耐磨钢组织和性能的影响

通过微观组织观察和力学性能测试,并结合磨损实验,研究了热轧+淬火、热轧+淬火+回火工艺对HB400级低合金高强耐磨钢板组织、力学性能及耐磨性的影响.结果表明:淬火后的钢板组织为板条状马氏体,具有一定的强韧性和耐磨性.250℃回火后获得回火马氏体组织,且在强度、硬度降低幅度不大的情况下,改善了耐磨钢的韧性,钢板的耐磨性最好.     

NM360耐磨钢回火工艺优化的研究

针对NM360耐磨钢板回火不充分、内应力没有充分释放的问题,研究了不同回火温度对NM360耐磨钢板的显微组织和力学性能的影响,并对回火工艺进行了优化。结果表明,耐磨钢在(900±10)℃保温12 min后淬火并在450℃回火时,随着回火时间的延长,试样的硬度逐渐降低,冲击吸收功先增大后减小,在回火时间为2.5 h时达到最大值。淬火后在300~400℃回火,耐磨钢处于回火脆性区。在450℃回火2.5 h时,耐磨钢获得大量回火马氏体组织,使钢具有较高的强度和高韧性,达到最佳的力学性能。通过回火工艺的优化,最终确定的最佳回火温度为450℃,最佳回火保温时间为2.5 h。     

水电用SX780CFZ35特厚板热处理工艺研究

针对水电用SX780CFZ35特厚钢板需具备易焊接、高强度、良好的塑性和低温韧性的要求,研究了热处理工艺对其力学性能及金相组织的影响。结果表明,在相同淬火温度下,钢板屈服强度、抗拉强度随回火温度的升高而降低,但冲击功随回火温度的升高而升高,屈强比则呈先上升后下降的趋势。在相同回火温度下,随淬火温度的升高,钢板强度增加,冲击功降低。820 ℃淬火,钢板组织存在较大比例未溶铁素体,为贝氏体和细小铁素体双相组织;860 ℃以上淬火,钢板组织为贝氏体,回火后为回火索氏体组织。热处理工艺为900 ℃淬火+620 ℃ 回火时,钢板冲击功达到100 J以上,强度依然能符合技术协议要求,为最佳热处理工艺。     

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.     

THERMODYNAMICS STUDY ON THE DECOMPOSITION OF CHROMITE WITH KOH

Institute of Process Engineering, Chinese Academy of Sciences, China, has proposed a method for oxidative leaching of chromite with potassium hydroxide. Understanding the mechanism of chromite decomposition, especially in the potassium hydroxide fusion, is important for the optimization of the operating parameters of the oxidative leaching process. A traditional thermodynamic method is proposed and the thermal decomposition and the reaction decomposition during the oxidative leaching of chromite with KOH and oxygen is discussed, which suggests that chromite is mainly destroyed by reactions with KOH and oxygen. Meanwhile, equilibrium of the main reactions of the above process was calculated at different temperatures and oxygen partial pressures. The stable zones of productions, namely, K2CrO4 and Fe2O3, increase with the decrease of temperature, which indicates that higher temperature is not beneficial to thermodynamic reactions. In addition, a comparison of the general alkali methods is carried out, and it is concluded that the KOH leaching process is thermodynamically superior to the conventional chromate production process.     

INFLUENCE OF HEAT TREATMENT ON DAMPING BEHAVIOUR OF THE MAGNESIUM WROUGHT ALLOY AZ61

The effect of isochronal heat treatments for 1h on variation of damping, hardness and microstructural change of the magnesium wrought alloy AZ61 was investigated. Damping and hardness behaviour could be attributed to the evolution of precipitation process. The influence of precipitation on damping behaviour was explained in the framework of the dislocation string model of Granato and Lücke.     

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。     

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).     

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.     

Using Finite Element and Contour Method to Evaluate Residual Stress in Thick Ti-6Al-4V Alloy Welded by Electron Beam Welding

This work was to reveal the residual stress profile in electron beam welded Ti-6Al-4V alloy plates(50 mm thick) by using finite element and contour measurement methods.A three-dimensional finite element model of 50-mmthick titanium component was proposed,in which a column–cone combined heat source model was used to simulate the temperature field and a thermo-elastic–plastic model to analyze residual stress in a weld joint based on ABAQUS software.Considering the uncertainty of welding simulation,the computation was calibrated by experimental data of contour measurement method.Both test and simulated results show that residual stresses on the surface and inside the weld zone are significantly different and present a narrow and large gradient feature in the weld joint.The peak tensile stress exceeds the yield strength of base materials inside weld,which are distinctly different from residual stress of the thin Ti-6Al-4V alloy plates presented in references before.     

Microstructures and Tensile Properties of Ultrafine-Grained Ni–(1–3.5) wt% SiC_(NP) Composites Prepared by a Powder Metallurgy Route

Silicon carbide nanoparticle-reinforced nickel-based composites(Ni–Si CNP),with a Si CNPcontent ranged from1 to 3.5 wt%,were prepared using mechanical alloying and spark plasma sintering.In addition,unreinforced pure nickel samples were also prepared for comparative purposes.To characterize the microstructural properties of both the unreinforced pure nickel and the Ni–Si CNPcomposites transmission electron microscopy(TEM) was used,while their mechanical behavior was investigated using the Vickers pyramid method for hardness measurements and a universal tensile testing machine for tensile tests.TEM results showed an array of dislocation lines decorated in the sintered pure nickel sample,whereas,for the Ni–Si CNPcomposites,the presence of nano-dispersed Si CNPand twinning crystals was observed.These homogeneously distributed Si CNPwere found located either within the matrix,between twins or on grain boundaries.For the Ni–Si CNPcomposites,coerced coarsening of the Si CNPassembly occurred with increasing Si CNPcontent.Furthermore,the grain sizes of the Ni–Si CNPcomposites were much finer than that of the unreinforced pure nickel,which was considered to be due to the composite ball milling process.In all cases,the Ni–Si CNPcomposites showed higher strengths and hardness values than the unreinforced pure nickel,likely due to a combination of dispersion strengthening(Orowan effects) and particle strengthening(Hall–Petch effects).For the Ni–Si CNPcomposites,the strength increased initially and then decreased as a function of Si CNPcontent,whereas their elongation percentages decreased linearly.Compared to all materials tested,the Ni–Si CNPcomposite containing 1.5% Si C was found more superior considering both their strength and plastic properties.     

Directional Growth of Tin Crystals Controlled by Combined Solute Concentration Gradient Field and Static Magnetic Field

A new method was introduced to achieve directional growth of Sn crystals. Microstructures in liquid(Pb)/liquid(Sn) diffusion couples were investigated under various static magnetic fields. Results show that the β-Sn crystals mainly reveal an irregular dendritic morphology without or with a relatively low static magnetic field(B0.3 T). When the magnetic field is increased to 0.5 T, the β-Sn dendrites close to the final stage of growth begin to show some directional character. With a further increase in the magnetic field to a higher level(0.8–5 T), the β-Sn dendrites have an enhanced directional growth character, but the dendrites show a certain deflection. As the magnetic field is increased to 12 T, the directional growth of the β-Sn dendrites in the center of the couple is severely destroyed. The mechanism of the directional growth of the β-Sn crystals and the deflection of the β-Sn crystals with the application of static magnetic field was tentatively discussed.