轴承钢和阀门钢线材的生产工艺

简要介绍了重庆钢铁股份有限公司高速线材厂的生产设备概况;为在普碳钢生产线上生产轴承钢、阀门钢线材,通过合理控制加热、轧制、控制冷却工艺,不仅使设备运行稳定,而且满足了用户对产品的外形尺寸、性能等要求。     

Mg-Nd-Zn-Zr稀土镁合金的热变形行为

采用GLEEBLE-1500热模拟机对Mg-Nd-Zn-Zr稀土镁合金在温度为250～450.℃、应变速率为0.002～0.100.s-1、最大变形程度为60%的条件下, 进行高温压缩模拟实验研究. 分析了实验合金在高温变形时的流变应力和应变速率及变形温度之间的关系, 计算了变形激活能和应力指数, 并研究了在热压缩过程中组织的变化, 为确定该稀土镁合金的挤压温度提供了实验依据. 结果表明: 合金的峰值流变应力随应变速率的增大而增加, 随温度的升高而降低; 合金的变形激活能在300～400.℃内变化不大, 而在400～450.℃时增加很大; 根据实验分析认为该稀土镁合金挤压温度定在350～400.℃左右为宜; 在350.℃左右顺利挤出的实验合金有很好的力学性能: σb=275.5.MPa, δ=13.5%.     

新型铸造镁合金开发现状

总结了近年来镁合金在高温抗蠕变、高韧性、高强度、高耐蚀性、降低成本和改善工艺性六大热点研究方向上取得的典型研究成果，重点阐述了对高温抗蠕变铸造镁合金的研究。并从热力学角度分析了镁合金中可能出现的各相对镁合金高温蠕变过程的影响，叙述了Mg-Al、Mg-Zn和Mg-RE系耐热合金的最新发明。     

分流挤压镁合金管材工艺研究

用分流挤压方法可生产挤压比不大于68，壁厚不小于1．5mm的非薄壁镁合金管材，其表面基本上无烧损、无横裂纹等缺陷。主要工艺参数：挤压筒温度250-350℃，镁棒温度320-380℃，模具预热温度300-380℃。模具及其内残余镁合金重复加热可保证模具多次使用，不用清洗。     

Thermal cross-linking and anti-meltdrop properties of copolyester containing phosphorus/magnesium salt composites by in situ polymerization

Polyester is widely used in household products because of its good mechanical properties and wears resistance, but polyester is easy to ignite and inclined to produce droplet, so its application range is limited. The cross-linkable magnesium hydroxide nanoparticles were incorporated into flame-retardant polyester, which enables the phosphorus-containing copolyester with thermal cross-linking and anti-meltdrop properties. The nanoparticles were achieved by in situ polymerization and acted as a nucleating agent for improving the crystalline properties of the copolyester. Furthermore, the nanoparticles also enhanced anti-meltdrop properties and reduced the heat and gas release during the combustion process of the copolyester. The maximum heat release rate and total smoke release reduced by 39.8% and 74.4% compared with pure polyester. Specifically, the combustion products of the nanoparticles and phosphorus flame retardant could act a barrier role by covering the carbon layer to isolate air and heat, thereby resulting in excellent anti-meltdrop properties. The simple modification method reported here realizes the collaborative modification of flame retardant and anti-meltdrop properties of phosphorous flame-retardant copolyesters by thermal cross-linking.     

Mg-Al-Zn（RE）镁合金轧制变形行为及强化机制

针对典型的Mg-Al-Zn系AZ31变形镁合金以及添加了0．8％Ce和0．8％Nd的AZ31镁合金，研究了合金在轧制加工过程中组织与性能的变化以及稀土元素对合金的影响，并探讨了合金的主要强化机制。结果表明：Mg-Al-Zn系合金轧制加工过程中加丁硬化严重，容易发生脆性断裂。添加稀土元素后的合金强度和塑性都有明显提高，稀土元素可形成Al4ce等含稀土化合物，起到细晶强化和第二相强化作用。     

轧制工艺对高碳钢线材性能影响的研究

研究了高碳钢线材轧制过程中终轧温度、吐丝温度和冷却速度对线材性能的影响,并采用数值优化方法建立了性能预测模型,其结果表明,模型计算精度较高。     

THE APPARENT VISCOSITY OF SEMI-SOLID AZ91D ALLOY AT STEADY STATE

The rheological behavior of semi-solid AZ91D at steady state is studied using a Couette type viscometer in the present paper. The results show that the apparent viscosity of semi-solid AZ91D at the steady state increases with the solid fraction increasing, and goes up sharply when the solid fraction reaches a certain value, which is called critical fraction. In addition, the apparent viscosity of semi-solid AZ91D at the steady state takes on a distinct downtrend with the shearing rate increasing, which indicates a strong shear thinning property. In addition, the critical solid fraction becomes higher under larger shearing rate, owing to the more globular shape of the solid particles. Based on the present experiment results, an empirical equation is built as that, relating the steady state apparent viscosity of semi-solid AZ91D with the solid fraction fs andshearing rate (?) at the same time: ηapp=10.74exp(6.95fs)(?)-0.86.     

Preparation and hydrogen sorption properties of Mg-Cu-Y-H systems

Mg-xwt.%CuY (x=15, 20, 25) composites were successfully prepared by reactive mechanical alloying (RMA).X-ray diffraction (XRD) measurement shows that main phases of the as milled composites are MgH2 and Mg2Cu, and they converted into Mg and MgCu2 after dehydrogenation, respectively.Pressure-Composition-Isotherm (PCI) test shows that the composites exhibit double pressure plateau at each isothermal desorption process.The hydrogen absorption and desorption kinetics of the composites become worse with increasing x content, indicating that Mg-Cu phase has a negative effect on the hydrogen sorption properties of the composites.It is supposed that the good hydrogen sorption properties of the composites attribute to the catalyst effect of yttrium hydride distributed in Mg substrate and the particles size reduction and crystal defects formed by RMA.