Gleeble 3800热模拟试验机在宝钢的典型应用与功能开发

热模拟试验可研究成分与各工艺参数对组织和性能的影响，用于指导产品设计和实际生产工艺的制定，还有助于建立数学模型。文章介绍了Gleeble 3800热／力模拟试验机在宝钢实际应用中的几个典型试验，包括高温热塑性试验、多道次变形试验、冷轧薄板相转变点试验和HAZ焊接热影响区热模拟试验等。这些试验可用来解决连铸、轧钢和冷轧产品热处理生产中存在的一些问题。     

PLC控制系统双机热备及可靠性设计与实现

可编程序控制器(PLC)是专门为工业生产环境设计的控制装置。总结了PLC控制系统的设计原则、内容、步骤和方法，并探讨了PLC双机热备用设计及可靠性设计方面要考虑的主要问题，结合工程设计经验提出可行的解决办法。     

Microstructural Evolution of Creep-Induced Cavities and Casting Porosities for a Damaged Ni-based Superalloy Under Various Hot Isostatic Pressing Conditions

The microstructural evolution of casting porosities and creep-induced cavities for a damaged nickel-based superalloy under different hot isostatic pressing(HIP) conditions was investigated in order to understand the effects of HIP parameters on the healing behavior of micropores. A number of small-sized creep cavities formed during long-term service and large-sized porosities formed during the casting process were observed. These microdefects were partially healed after treated at high temperature of 1100 °C combined with 150 MPa pressure for 2 h, together with the formation of the socalled concentrically oriented c0 rafting structure. When HIP temperature was increased to 1150 and 1175 °C, both the amount and the size of the microdefects were decreased. The concentrically oriented c0 rafting around creep cavities became more remarkable, and the primary c0 denuded zone was also formed between the raft structure and the cavity.Energy-dispersive X-ray spectroscopy analysis revealed that the c matrix solute atoms diffused toward the cavity under the concentration gradient, whereas the c0-forming elements diffused in a negative direction. When increasing HIP temperature up to 1200 °C, the micropores were hardly observed, indicating that both casting porosities and creep-induced cavities had almost been healed. Meanwhile, the c0 rafting structure disappeared since HIP temperature was beyond the c0 solvus temperature. It is revealed by the experimental results that the atomic diffusion could mainly dominate the healing process of micropores.     

Thermal properties of new varieties of yam starches

Starches isolated from yam varieties of Dioscorea alata and Dioscorea cayenensis‐rotundata species were prepared at different time–temperature conditions and characterised by DSC, amperometric iodine titration, light microscopy and rheology and compared to native and chemical modified tapioca starches. The observation by light microscopy showed different morphologies of the granules when heated above 100°C and the tendency for disintegration decreased in the order native tapioca starch > yam starch > modified tapioca starch. Differences between yam and tapioca starches were also revealed by DSC. Yam starch enthalpy is higher than tapioca starch, but the peak temperature is low. However, the significant differences between yam and the other tested starches were found in terms of their rheological behaviour. The viscosity of yam starch was very stable at high temperatures on the viscograph. With this property, yam starch can be used as thickening and gelling agent in food.     

耐蚀热镀锌钢板在汽车工业中应用的进展

介绍了耐蚀热镀锌钢板的性能特点及其发展情况,对其在汽车工业中的应用现状进行了详细评述,并对发展我国汽车热镀锌钢板提出了几点建议。     

Influence of Microstructural Evolution on the Hot Deformation Behavior of an Fe–Mn–Al Duplex Lightweight Steel

The hot deformation behavior of Fe–26 Mn–6.2 Al–0.05 C steel was studied by experimental hot compression tests in the temperature range of 800–1050 °C and strain rate range of 0.01–30 s21 on a Gleeble-3500 thermal simulation machine. The microstructural evolution during the corresponding thermal process was observed in situ by confocal laser scanning microscopy. Electron backscattered diffraction and transmission electron microscopy analyses were carried out to observe the microstructural morphology before and after the hot deformation. Furthermore, interrupted compression tests were conducted to correlate the microstructural characteristics and softening mechanisms at different deformation stages.The results showed that hot compression tests of this steel were all carried out on a duplex matrix composed of austenite and d-ferrite. As the deformation temperature increased from 800 to 1050 °C, the volume fraction of austenite decreased from 70.9% to 44.0%, while that of d-ferrite increased from 29.1% to 56.0%. Due to the different stress exponents(n) and apparent activation energies(Q), the generated strain was mostly accommodated by d-ferrite at the commencement of deformation, and then both dynamic recovery and dynamic recrystallization occurred earlier in d-ferrite than in austenite.This interaction of strain partitioning and unsynchronized softening behavior caused an abnormal hot deformation behavior profile in the Fe–Mn–Al duplex steel, such as yield-like behavior, peculiar work-hardening behavior, and dynamic softening behavior, which are influenced by not only temperature and strain rate but also by microstructural evolution.     

无堆焊衬里热壁加氢反应器的H2S腐蚀

介绍了在压力为4．0MPa、温度为385℃条件下，使用的13CrMo44无堆焊衬里热壁加氢反应器的H2S腐蚀情况，分析了减缓H2S腐蚀的影响因素，以及反应器使用中应注意的问题。     

Self-propagating high-temperature synthesis of advanced ceramics MoSi2–HfB2–MoB

This study focuses on the investigation of the macrokinetic features of SHS (combustion synthesis) of elemental mixtures Mo–Hf–Si–B, in particular the mechanisms of structure and phase formation in the combustion front as well as the structure and properties of consolidated ceramics. Two routes for the fabrication of the composite SHS powder in system MoSi₂–HfB₂–MoB were used: (1) synthesis using Mo–Si–B and Hf–B mixtures followed by mixing of the combustion products and (2) synthesis using the four-component Mo–Hf–Si–B mixture. Dense ceramic samples with a homogeneous structure and low residual porosity (0.8–3.6%) were prepared by hot pressing of SHS powders. Although the particles size distribution and phase composition of SHS powders are similar for both synthesis routes, the structure and properties of both the composite SHS powders and hot-pressed ceramics differ considerably. Synthesis using the four-component Mo–Hf–Si–B mixture allows one to produce hierarchically ordered nanocomposite material with improved mechanical properties: hardness up to 17.6?GPa and fracture toughness up to 7.16?MPa?m^1/2.     

Characterising pre-preg and non-crimp-fabric composite single lap bonded joints

Pre-preg and non-crimp-fabric composite single lap bonded joints were manufactured and investigated to characterise the bond quality and static failure behaviour. A two-part epoxy adhesive was employed to bond composite laminates. The composite panels, which were treated with low pressure oxygen plasma, were bonded in a hot drape former and then cut to manufacture single lap bonded joints. The joints were examined using X-ray microtomography to evaluate the bond quality achieved in the hot drape former. Quasi-static tensile tests were conducted on the pre-preg and non-crimp-fabric composite single lap bonded joints. The fracture surfaces were examined using optical and scanning electron microscopy. The static failure behaviour and failure patterns observed in the two joint types were compared and discussed.     

A review of diamond synthesis by CVD processes

Diamond has some of the most extreme mechanical, physical and chemical properties of all materials. Within the last 50 years, a wide variety of manufacturing methods have been developed to deposit diamond layers under various conditions. The most common process for diamond growth is the chemical vapor deposition (CVD). Starting from the first publications until the latest results today, a range of different developments can be seen. Comparing the basic conditions and the process parameters of the CVD techniques, the technical limitations are shown. Processes with increased pressure, flow rate and applied power are the general tendency.