轴承钢材在连续式退火炉中球化退火工艺试验

轴承钢材在带有保护气氛的辊底式钢材连续退火炉中,进行球化退火,可获得球化组织均匀细散,表面无氧化,脱炭轻微、硬度均匀一致的高质量退火材。本文总结了轴承钢在连续式退火炉中进行球化退火时,各种工艺参数对球化组织和硬度的影响。为改善炭化物的颗粒度和分散度,获得不同级别的球化组织和退火硬度,提供了可靠的球化退火工艺。     

中碳钢球化退火行为和力学性能的研究

采用常规双相区球化退火和亚温球化退火工艺研究了常规轧制（CR）和控轧控冷（CRC）的中碳钢SWRCH35K的球化退火行为和力学性能。结果表明，与传统的双相区球化退火相比，亚温球化退火时碳化物球化进程明显加快，球化率高，且碳化物比较细小，具有良好的塑性和冷成形性，采用亚温球化退火处理可明显地缩短球化退火时间。控轧控冷的中碳钢线材尽管具有比较粗大的珠光体组织，但因有相当部分的珠光体发生退化，其球化退火进程要明显快于细珠光体组织。     

临界区等温球化退火对低密度轴承钢组织和硬度的影响

摘要：临界区等温球化退火是实现高碳轴承钢中片状珠光体球化的主要热处理方式,其将片状珠光体转变为粒状珠光体,改善轴承件的可加工性及组织均匀性。研究了临界区等温球化退火工艺对低密度含Al轴承钢微观组织演化及硬度的影响。研究结果表明,轴承钢钢中高含量Al的添加可以提高临界区等温球化退火温度,缩短球化时间,将珠光体的硬度降低至300HV以下。但是,临界区等温球化保温过程中有石墨颗粒形成,石墨颗粒的产生虽然能够有效地降低球化后钢材硬度,但是部分石墨颗粒在最终的奥氏体化过程中难以溶解进入钢材基体,未溶解的石墨颗粒不仅增加了组织的不均匀性,而且降低了轴承钢硬度。所以,较长时间退火保温的临界区球化退火方式并不适用于低密度高碳高Al轴承钢。     

高碳铬轴承钢棒材轧后快速冷却工艺的研究

高碳铬轴承钢热轧后利用轧后余热进行快速冷却,对于控制网状碳化物的析出,获得理想的球化退火预备组织,缩短退火周期,提高球化退火质量是一种有效的手段。本文研究了高碳铬轴承钢轧后快冷过程中钢材内部组织的变化和表面裂纹的情况及其影响因素。为实现轴承钢轧后快速冷却工艺和装置提供技术参数。     

60钢冷拔钢丝的球化退火

研究了 6 0钢冷拔钢丝的球化退火工艺。结果表明 ,在退火温度 70 0℃、保温 3～ 5h情况下 ,6 0钢冷拔钢丝可获得良好的球化组织 ,具有较低的抗拉强度和良好的塑性。     

38CrMoAlA钢组织和硬度对切削性能的影响

对38CrMoAlA钢分别进行热轧态、退火态及正火态显微组织和性能的分析,并利用CW6263C马鞍车床进行钢材镗孔切削性能试验。试验结果表明:热轧态、正火态、退火态时38CrMoAlA钢的硬度值依次降低。38CrMoAlA钢热轧态组织以贝氏体为主,并含有少量铁素体和珠光体,正火态组织以铁素体和珠光体为主,退火态组织以类球化组织为主,并保持贝氏体位相。从镗孔试验结果看,38CrMoAlA钢热轧态易断削,镗孔阻力较大;38CrMoAlA钢正火态,易断削,镗孔阻力较小;38CrMoAlA钢退火态不易断削,车削颜色发蓝,镗孔阻力较大。最终确定38CrMoAlA轧材镗孔最佳状态应为正火态,组织以铁素体和珠光体为主,硬度在230~240 HB。     

预变形上贝氏体组织对GCr15轴承钢球化退火质量的影响

对GCr15轴承钢的预变形上贝氏体组织形态以及不同形变量的预变形上贝氏体组织对球化退火质量的影响进行了分析,并提出了最佳的球化退火工艺。     

GCr15球化退火行为和力学性能的研究

采用等温球化退火和周期球化退火工艺分别研究了常规轧制（CR）和控轧控冷（TMCP）的GCr15钢的球化退火行为和力学性能。结果表明,轧制工艺对GCr15钢组织影响显著;在等温球化退火处理制度下常规轧制（CR）和控轧控冷（TMCP）试样球化效果差别较小;在周期球化退火处理制度下,控轧控冷（TMCP）试样可获得细小均匀的球化组织,其球化效果明显优于常规轧制（CR）试样,且球化退火时间比宝钢特钢现行的等温球化退火工艺缩短了6 h,可显著提高生产效率。     

退火温度对刃具钢6CrW2Si组织和硬度的影响

为满足用户加工硬度的特殊需求(硬度≤210HBW),降低6CrW2Si钢硬度,本文利用连轧厂实际辊底式退火炉进行了不同退火温度的退火试验,并借助金相显微镜对不同退火温度下的组织进行了分析,以确定最佳的退火温度。结果表明:6CrW2Si的退火硬度与退火温度有关,随着退火温度的升高,硬度先下降后上升,当退火温度为810℃时,钢材平均硬度值最低(193 HBW左右),球化组织为均匀的球化珠光体组织。     

稀土镁铸态铁素体球墨铸铁试验

我国铁索体高韧性球铁有两种牌号:QT40—17和QT42—10。它们一般是经高温和低温两阶段石墨化退火或低温石墨化退火得到,也有铸态直接获得的。铸态铁素体球铁由于不用热处理,节省能源,缩短生产周期,减轻工人劳动强度,     

转炉炉壳热应力分析

根据实际转炉建立实体模型。以有限元为手段,考虑了炉衬和炉壳材料的物性参数随温度变化的特点和炉衬与炉壳之间膨胀间隙,计算了转炉炉壳在温度载荷和炉衬膨胀压力同时作用下的热应力。所得结果可为转炉炉壳设计提供依据。     

The effect of amount of possession of the trait of hostility on accuracy of perception of hostility in others.

Some theories of personality hold that an individual's perception of others is influenced by his own personality characteristics; more specifically, that a trait of low social value will be projected more into others, and that insight into the possession of these characteristics reduces this distortion. These 2 hypotheses were tested by having a group of college students rate each other (including themselves) on degree of friendliness or hostility. Agreement with group rating about self yielded the insight score. In general, the hypotheses were supported; the "friendly" Ss were most accurate in their perception of others, and insight was positively associated with accurate perception. From Psyc Abstracts 36:04:4HL16M. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Comparison of rates of infection of two methods of emergency ventricular drainage

The rates of infection of two methods of external ventricular drainage in use at Atkinson Morley's Hospital--namely, (a) percutaneous drainage with Rickham reservoirs and (b) tunnelled ventriculostomies--were compared in this retrospective review. Percutaneous drainage of CSF with Rickham reservoirs was associated with a 27% rate of infection as identified by positive microbiological cultures; tunnelled ventriculostomy catheters had a 10% infection rate. The difference in the infection rate between the two methods was statistically significant (P < 0.015). Other variables examined, including the age and sex of the patients and the reasons for ventricular drainage, were not associated with an increased rate of infection. Most infections from either method were caused by a coagulase negative staphylococcus. The average duration of ventricular drainage before identification of positive cultures was 5.7 days for Rickham reservoirs and 6.0 days for ventriculostomies.     

浅析《野草》的版画特征

鲁迅先生一生热爱美术作品,对版画中木刻兴趣尤甚.<野草>作为其"写心之作",亦呈现出一些与木刻版画一致的审美特征:一是具有木刻版画的色彩特征,多对比、多冷色,有阴郁的美感;二是具有木刻版画的力度特征,环境描写、人物刻画处处刀锋毕现,遒劲有力,有一种"力之美".     

四辊破碎机车刀架的改造

针对四辊破碎机车刀架车削中存在的几个问题,详细介绍了电动车刀架的结构和工作原理,建立主要设计参数的数学表达式,并进行适当的分析。改造后,这种电动车刀架运行平稳、可靠、方便、省力,取得了预期的效果。     

Rehabilitation of disorders of the breaking of voice

The adolescent's breaking of the voice is the result of the substitution of the chest voice (or heavy mechanism) for the head voice (or light mechanism). In cases of late breaking, the voice is abnormally high-pitched and feeble, often with a distorted timbre, while the larynx is normal and pubescent. Such people are generally not fully aware of their voices' real nature. Therapy classically resorts to laryngeal manipulations, of which a new technique is put forward. Another therapeutic approach is based, on the one hand, on critical listening compared with a control male voice, thus enabling the subject to become aware of his own voice, and, on the other hand, on high intensity work which helps passing from head to chest voice.     

2008年中国电解金属锰发展态势浅析

对中国电解金属锰发展的市场态势、价格行情以及原材料供应情况作了初步分析,提出我国电解金属锰行业挑战与机遇并存,只要抓住机遇、迎接挑战、夯实基础、科技创新,电解金属锰行业前景将会更加光明。     

Replication of dimensions of locus of control.

Employed 120 male and 113 female undergraduates in a replication of H. L. Mirels's (see record 1970-10386-001) study which found 2 factors in analyzing responses to 23 items on Rotter's Internal-External Control Scale. The same polar dimensions of "luck" as the arbiter of life events as opposed to personal control were found as well as a 2nd dimension of degree of control over political and social institutions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)