预冷等温球化退火工艺对Cr12型模具钢组织性能的影响

通过对Cr12型模具钢常规球化退火工艺的改进,得到了预冷等温球化退火新工艺。并对不同球化温度、不同退火保温时间对钢组织性能的影响进行了探讨。结果表明:改进的预冷等温球化退火新工艺合理可行,可获得硬度低于200HB、碳化物颗粒均匀细小的球化效果。球化温度和退火保温时间对组织性能均有一定影响。Cr12型模具钢理想的球化退火工艺为:球化温度940℃,保温至透烧,出炉油冷到400℃,进行730℃等温退火处理,冷却速度为<30℃/h至200℃出炉。     

一种新型冷轧辊用钢的组织演变

本文以一种新型冷轧辊用钢为研究对象,借助金相显微镜和扫描电子显微镜分析了试验钢在正火、球化退火、淬火、回火过程中的组织演变,研究了碳化物的成分变化和溶解析出行为。结果显示,试验钢正火后得到马氏体+部分颗粒状和少量块状碳化物的显微组织;球化退火后的显微组织为铁素体基体上分布有大量颗粒状碳化物+少量块状碳化物,球化退火组织评定为为2~3级;淬火后的组织为马氏体+部分颗粒状和少量块状碳化物;三次回火后的组织为回火马氏体+部分颗粒状和少量块状碳化物。试验钢中的块状碳化物在整个热处理过程中始终存在,1100℃以下奥氏体化时只发生边缘部分的少量溶解。颗粒状碳化物主要为M23C6型,在热处理过程中存在明显的溶解和析出行为,1100℃以下奥氏体化时部分溶解。     

冷轧辊用9Cr2MoRe钢球化退火工艺研究

稀土元素能提高9Cr2Mo冷轧辊钢的热疲劳性能、低周疲劳性能、塑、韧性以及细化奥氏体晶粒、改善碳化物的形态和变质夹杂物的作用,通过添加稀土元素Re以及合理的热处理方式来改善冷轧辊的性能,用正交设计法研究了电渣熔铸9Cr2MoRe钢碳化物球化退火工艺,通过对调质球化工艺中各因素对球化效果影响的综合分析,重点讨论了9Cr2MoRe冷轧辊用钢球化退火工艺。     

冷轧Mg-9Li-1Zn合金的退火热处理工艺

以改善冷轧Mg-Li系合金的变形能力为目的,系统研究了冷轧变形后的Mg-9Li-1Zn合金的退火热处理工艺,分析了退火温度和退火时间对合金组织和性能的影响.研究结果表明:Mg-9Li-1Zn合金适宜的退火温度为280~300℃,退火温度过高会出现晶粒长大,表面脱锂等现象.300℃退火60 min后,合金的维氏硬度值为426.7 MPa,充分完成再结晶软化的合金在后续冷轧时总变形率可达70%.合金的退火时间以保证α相的充分球化及组织的均匀化为准则,实验中确定的最佳退火制度为300℃保温60 min.     

T10 A钢快速球化退火工艺研究①

以T10A钢为研究对象,通过省去随炉降温过程,采用延长保温时间的方法,探寻节约时间和成本的球化退火工艺。利用光学显微镜和扫描电子显微镜(SEM)观察样品的表面形态,Image pro plus 6.0进行碳化物颗粒统计分析。实验结果表明:Φ13 mm的T10A钢在700℃入炉升温至760℃保温10 min,迅速转移至690℃保温80 min后空冷,可获得碳化物球化程度CS3级组织,心部组织与表层组织的碳化物颗粒均匀性,均高于普通球化退火和等温球化退火,且硬度与等温球化退火一致。此球化退火工艺在保证质量的前提下,碳化物的球化时间极大缩短,可提高生产效率、降低成本、提高能源利用率,拥有较好的工业化应用前景。     

冷轧退火对共析珠光体钢组织球化超细化的影响

研究了冷轧变形并结合退火处理对共析钢组织球化超细化与性能的影响.结果表明:共析钢经冷轧形变量90%结合600～700 ℃退火得到了晶粒尺寸为亚微米级铁素体晶粒和颗粒状渗碳体的双相组织.颗粒状渗碳体的尺寸呈双峰分布.与传统球化处理工艺相比,球化时间明显缩短,球化组织细小;其原因是在冷变形过程中产生了高密度位错以及大量空位等缺陷,为碳原子的扩散提供了高速率扩散通道,促进了碳原子的扩散.细小渗碳体粒子在铁素体基体上的弥散分布可以用溶解-再析出机制来解释.冷轧后经700 ℃退火试样的拉伸塑性略有下降,屈服强度和抗拉强度大幅度提高,但屈强比较高.     

冷却速率和奥氏体化温度对40 Cr钢球化退火的影响

为探究奥氏体化温度和冷却速率对40Cr钢球化过程的影响,采用双相区球化退火研究了热轧态40Cr钢的球化退火行为和力学性能。奥氏体化温度从760℃提高到800℃,冷却速率从10℃·h-1上升到30℃·h-1,组织硬度随冷却速度呈V形变化,碳化物球化率随冷却速度变化正好与前者相反。奥氏体化温度为760℃,冷却速率为20℃·h-1所得到的球化组织球化率高,且碳化物细小,具有良好的冷成形性能,可大幅度缩短球化退火时间,显著提高生产效率。提出了球化退火过程中离异共析转变机制,控制好球化过程中奥氏体化温度、冷却速率及保温时间有利于离异共析转变的发生。     

双辊铸轧镁合金薄带冷轧实验研究

采用AZ31镁合金铸锭在实验室立式等径双辊铸轧机上进行铸轧试验;对铸轧带坯直接进行冷轧和冷轧后退火处理.研究了AZ31镁合金薄带立式双辊铸轧工艺及铸轧带坯进行冷轧、轧后退火过程的组织演变行为.采用合理的工艺参数,成功铸轧出镁合金薄带,同时由于双辊铸轧快速冷却和压力下凝固成形技术特点,改善了镁合金的凝固组织.对铸轧镁合金带坯直接进行冷轧,最大变形量可以达到40.7%.经过冷轧后的镁合金板材,在350℃下退火30~60 min,可以获得平均晶粒直径为9~10μm的等轴晶细晶组织.     

再结晶退火对含磷冷轧高强度钢板显微组织的影响

对含磷冷轧高强度钢板的再结晶退火工艺进行了研究，测定了含磷冷轧高强度钢的再结晶软化曲线，并得出再结晶温度。通过试样硬度的测定以及金相组织的观察分析，研究了冷轧高强度钢工艺、组织结构和硬度之间的关系。结果表明，冷轧高屈服强度钢的再结晶温度在450℃左右，再结晶完成温度大约为700℃：随着退火温度的升高，冷轧高强度钢再结晶组织晶粒不断粗大，渗碳体变化不明显，但其硬度呈明显下降趋势。     

热处理工艺对H13钢微观组织的影响

首先对H13进行了高温正火+球化退火的预备热处理,获得碳化物分布均匀、球化率高于95%的退火组织.进而对退火组织进行了淬火+回火最终热处理,研究了淬火温度对H13钢组织和硬度的影响.随着淬火温度的提高,溶解的合金碳化物增多,溶解的合金碳化物使基体中的碳含量和合金含量增多,淬火组织硬度得到了提高,大颗粒碳化物熔解为细小的碳化物,当淬火温度为1 100℃,保温1.5h,合金碳化物几乎全部溶解.对淬火组织进行了二次回火,回火使淬火过程中熔解的碳化物又重新弥散析出,且随着淬火温度的提高,回火硬度提高,碳化物更加细小,分布得更均匀.     

等通道转角挤压对铝青铜力学性能的影响

采用等通道转角挤压（ECAE）工艺对铝青铜(Cu 10%Al 4%Fe)进行热处理,研究了ECAE处理工艺中预热温度、挤压道次及退火处理对铝青铜外观形貌、微观组织及力学性能的影响.结果表明:在650 °C的预热温度下,铝青铜可以顺利通过ECAE挤压通道;随着ECAE挤压道次从1增至4,铝青铜的显微硬度、屈服强度及延伸率显著增加;经500 °C退火60 min处理后,铝青铜的力学性能最佳.     

预处理对GCr15轴承钢淬火组织与性能的影响

研究了球化退火和固溶+高温回火两种预热处理工艺对GCr15轴承钢淬火组织、硬度、冲击韧性和抗拉强度的影响.结果表明,两种预处理工艺都明显地细化了碳化物颗粒,其中经固溶+高温回火预处理的轴承钢具有较好的碳化物细化效果和细小晶粒的终处理组织,并获得了较高的硬度和抗拉强度值.在预处理都为球化退火工艺、终处理回火温度不同时,经较低回火温度(160℃)处理的轴承钢可获得良好的强韧性能.     

Effect of temper rolling on the bake-hardening behavior of low carbon steel

In a typical process, low carbon steel was annealed at two different temperatures (660℃ and 750℃), and then was temper rolled to improve the mechanical properties. Pre-straining and baking treatments were subsequently carried out to measure the bake-hardening (BH) values. The influences of annealing temperature and temper rolling on the BH behavior of the steel were investigated. The results indicated that the microstructure evolution during temper rolling was related to carbon atoms and dislocations. After an apparent increase, the BH value of the steel significantly decreased when the temper rolling reduction was increased from 0% to 5%. This was attributed to the increase in solute carbon concentration and dislocation density. The maximum BH values of the steel annealed at 660℃ and 750℃ were 80 MPa and 89 MPa at the reductions of 3% and 4%, respectively. Moreover, increasing the annealing temperature from 660 to 750℃ resulted in an obvious increase in the BH value due to carbide dissolution.     

Effect of continuous induction annealing on the microstructure and mechanical properties of copper-clad aluminum flat bars

Copper-clad aluminum (CCA) flat bars produced by the continuous casting–rolling process were subjected to continuous induction heating annealing (CIHA), and the effects of induction heating temperature and holding time on the microstructure, interface, and mechanical properties of the flat bars were investigated. The results showed that complete recrystallization of the copper sheath occurred under CIHA at 460°C for 5 s, 480°C for 3 s, or 500°C for 1 s and that the average grain size in the copper sheath was approximately 10.0 μm. In the case of specimens subjected to CIHA at 460–500°C for longer than 1 s, complete recrystallization occurred in the aluminum core. In the case of CIHA at 460–500°C for 1–5 s, a continuous interfacial layer with a thickness of 2.5–5.5 μm formed and the thickness mainly increased with increasing annealing temperature. After CIHA, the interfacial layer consisted primarily of a Cu₉Al₄ layer and a CuAl₂ layer; the average interface shear strength of the CCA flat bars treated by CIHA at 460–500°C for 1–5 s was 45–52 MPa. After full softening annealing, the hardness values of the copper sheath and the aluminum core were HV 65 and HV 24, respectively, and the hardness along the cross section of the CCA flat bar was uniform.     

Effects of simulated on-fire processing conditions on the microstructure and mechanical performance of Q345R steel

A series of simulated on-fire processing experiments on Q345R steel plates was conducted, and the plates’ Brinell hardness, tensile strength, and impact energy were tested. Microstructure morphologies were systematically analyzed using a scanning electron microscope with the aim of investigating the effect of the steel’s microstructure on its performance. All examined performance parameters exhibited a substantial decrease in the cases of samples heat-treated at temperatures near 700℃. However, although the banded structure decreased with increasing treatment temperature and holding time, it had little effect on the performance decline in fact. Further analysis revealed that pearlite degeneration near 700℃, which was induced by the interaction of both subcritical annealing and conventional spherical annealing, was the primary reason for the degradation behavior. Consequently, some nonlinear mathematical models of different mechanical performances were established to facilitate processing adjustments.     

激光晶化多晶硅的制备与XRD谱

对氢化非晶硅（a-Si∶H）进行了脱氢和不同能量密 度的准分子激光晶化多晶硅的实验, 对所得样品用X射线衍射表征. 针对多晶硅（111）面特征峰的强度、 晶面间距和宽化信息, 分析了激光功率密度对晶化多晶硅结晶度和应力的影响, 根据谢乐公式（Scherrer）估算了晶粒的大小, 得到用准分子激光晶化多晶硅的较佳工艺参数, 并且验证了激光辐射对薄膜材料作用的3种情况.     

On-line spheroidization process of medium-carbon low-alloyed cold heading steel

Conventionally manufactured 35CrMo cold heading steel must undergo spheroidization annealing before the cold heading process. In this paper, different types of deformation processes with various controlled cooling periods were operated to achieve on-line spheroidal cementite using the Gleeble-3500 simulation technique. According to the measured dynamic ferrite transformation temperature (A_d3), the deformation could be divided into two types: low temperature deformation at 810 and 780℃; “deformation-induced ferrite transformation” (DIFT) deformation at 750 and 720℃. Compared with the low temperature deformation, the DIFT deformation followed by accelerated cooling to 680℃ is beneficial for the formation of spheroidal cementite. Samples subjected to both the low-temperature deformation and DIFT deformation can obtain granular bainite by accelerated cooling to 640℃; the latter may contribute to the formation of a fine dispersion of secondary constituents. Granular bainite can transform into globular pearlite rapidly during subcritical annealing, and the more the disperse phase, the more homogeneously distributed globular cementite can be obtained.     

乙烯在过渡金属表面的吸附与分解

本文研究了乙烯（C2H4）在Ru(10 10^-)表面的吸附，在低温下（200K以上）乙烯可以在Ru(10 10^-)表面以上分子状态稳定吸附，在200K以上乙烯则发生了脱氢分解反应，TDS结果表明乙烯分解后的主要产物为乙烯（C2H2），乙烯分解后碳的1s能级向低结合方能向移动了0.3eV.     

山药基因组DNA的提取和RAPD反应条件的优化

研究了山药基因组DNA的提取方法;对Mg2+浓度、dNTPs浓度、引物浓度和Taq酶用量进行了优化,建立了最佳的RAPD反应体系:在25μL反应体系中Mg2+浓度为2.0 mmol.L-1,dNTPs浓度为0.25 mmol.L-1,引物浓度为20 pmol.L-1,Taq酶1.5 U,模板DNA为200 ng.扩增程序为:95℃预变性7 min;94℃变性30 s,36℃退火45 s,72℃延伸2 min,共35个循环;72℃终延伸10 min.     

热处理工艺对T8钢显微组织及硬度的影响

T8钢由于含碳量高,过剩碳化物极多,塑性和韧性差,若热处理工艺不合适,使材料在服役早期出现开裂和破碎的现象。通过SEM,OPM及XRD等试验方法,研究了T8钢组织和性能随球化退火时间、淬火温度及回火温度的变化。结果表明：T8钢在600℃球化退火2 h后,原始组织中的碳化物即可获得充分球化,以粒状形式细小均匀地分布在基体中,延长退火时间不显著改变碳化物的球化效果;试样经（770±10）℃保温,6 min油淬后,获得的隐晶马氏体组织硬度最高;试样经180~210℃回火1 h空冷后,消除了淬火过程中产生的残余应力,最终获得有球状碳化物均匀分布的隐晶马氏体组织,回火试样硬度较淬火态略有下降。