铁基烧结材料硬度与孔隙度的关系

提出了与表观硬度相对应的基体硬度的概念,分析了表观硬度与基体硬度之间的差异,通过对实验数据的分析处理,推导出了表观硬度,基体硬度和孔隙度θ三者之间的解析式,并进行了分析讨论和实验验证。     

弯管硬度检测问题的探究

基于表面硬度对弯管产品性能的重要性,通过采用里氏硬度仪和维氏硬度计对弯管进行试样检测和产品表面检测,比对发现里氏硬度仪自带硬度转换软件造成硬度转换值差异较大,不适宜直接用于评价弯管产品硬度性能;并分析探究其产生差异的原因,提出了如何正确地测量弯管表面硬度和对其结果进行评价的方法。     

影响20Cr13棒材硬度值因素的分析

通过对退火热处理工艺分析,对比各炉型退火处理参数与硬度的关系,确定降低钢材硬度的控制措施。     

钒对FT61钢调质后硬度及组织的影响

通过对加钒后FT61钢调质后硬度及组织的分析,得出钒元素可以明显提高FT61钢的淬火硬度和回火硬度,同时也能起到细化晶粒尺寸的作用。     

浅谈布氏硬度压痕测量装置的选用对试验结果的影响

通过采用读数显微镜、测量显微镜、布氏硬度测量系统以及设备自带测量压痕测量系统等压痕测量装置对布氏硬度压痕进行测量,分析不同装置在布氏硬度试验中对压痕测量的影响,最终得出在硬度压痕测量时需要多次复核,提高测量准确性.     

控制轧制对42CrMo钢组织与硬度的影响

针对用户提出42Cr Mo钢硬度偏高,采用控制轧制,通过调整不同的精轧轧制温度以分析对组织和硬度的影响。采用ZEISS型金相显微镜和硬度仪对其进行金相组织观察和硬度分析。结果表明,精轧轧制温度分别为950℃、820℃、780℃时,硬度平均值分别为276、222、216HB。     

Ni对低铍铜合金铸锭组织和硬度的影响

通过对不同Ni含量的铍铜合金进行微观组织分析、物相分析、TEM显微组织分析以及硬度检测,研究Ni含量对铍铜合金铸锭组织和硬度的影响。通过分析表明,Ni含量不同,低铍铜合金铸锭内部析出相形貌及其分布有明显差异,铍铜合金硬度随Ni含量的增加先上升后下降,在0.98wt.%达到最大值。     

热处理制度对6082铝合金棒材硬度和电导率的影响

采用正交试验的方法研究了热处理制度对6082铝合金棒材硬度和电导率的影响,并通过皮尔逊相关系数公式计算并分析了硬度和电导率之间的相关性。结果表明,时效温度是影响棒材电导率的最主要因素,固溶温度对棒材硬度影响的因素最大,时效保温时间对硬度和电导率的影响较小。通过生产验证,采取520℃+195℃/8h的热处理制度,6082铝合金棒材的硬度95HB、电导率26.5MS/m。     

降低热轧中、高碳窄带钢硬度的探讨

热轧中、高碳窄带钢硬度偏高，不利于冷轧加工。通过对该产品大量硬度测试和数据采集，分析硬度偏高的原因，提出了热轧后温降速度影响中、高碳窄带钢硬度的观点。采取针对措施，有效地降低了热轧中、,主碳带钢的硬度。     

MC5中间辊硬度偏低、不均匀的原因分析

通过对批量性MC5中间辊硬度偏低、不均匀的情况进行试验、分析,发现淬火温度偏高导致残余奥氏体量增加,造成回火后硬度偏低;残余奥氏体在350℃左右回火时转变为下贝氏体类组织,使得残余奥氏体在回火后对硬度没有贡献.     

Simulation of Case Depth of Cementation Steels According to Fick＇s Laws

 The carburizing process is the enrichment of the depth of low carbon steels with carbon. It leads to samples with a combination of high surface hardness and high core toughness and to an impact strength that is required for many engineering parts. The material studied is a low carbon steel. The carbon content is little in this type of steel (wC=0.2%). The calculation of case depth is very important for cementation steels that are hardened in the carburizing process. The effective case depth is defined as the perpendicular distance from the surface to a place at which the hardness is HV 550. Nowadays, a great number of studies have been carried out on the simulation of effective case depth, but no studies have been conducted to determine the numerical relation between the total case depth on one hand and the carburizing time and the effective case depth on the other hand. The steel specimens were subjected to graphite powder. Then, they were heat treated at 925 ℃ for about 3, 5, 8 and 12 h, respectively. Then, these parts were quenched in oil. To determine the effective case depth, the microhardness test was performed on the cross-section of specimens. Plotting the case depth vs carburizing time, the required conditions for obtaining the specified case depth were determined. Also, the comparison between the case depths in numerical solution and the actual position in pack carburizing was performed.     

齿轮钢中渗氮层深度及含量的测定方法

齿轮钢中渗氮层深度和含量测定,对衡量渗氮工艺是否合适至关重要。实验以20MnCrS5齿轮钢为试验材料,摸索出电子探针法(EPMA)测定渗氮层的最佳试验参数为:加速电压10 kV,束流100 nA,束斑直径1 μm,步径1 μm。首先,利用电子探针的面扫描功能,对渗氮层从表面到基体进行二维和三维面分布定量化分析,从结果可以看出,表层有一个富集的氮化层,厚度约为10 μm,最高处氮含量(质量分数,下同)达到8.46%,氮化层以内的氮含量在0.84%左右,渗氮层总深度约为600 μm。其次,对比了电子探针线分析法与硬度法的结果,电子探针法测得的渗氮层总深度与硬度法测得的基体硬度值时深度一致,都约为600 μm,且能同时给出不同渗氮层厚度与氮含量的变化曲线。因此,电子探针法作为硬度法的补充方法,可以同时得到准确的渗氮层深度和氮含量,可以作为衡量渗氮工艺是否合适的依据。     

齿轮钢中渗氮层深度及含量的测定方法

齿轮钢中渗氮层深度和含量测定,对衡量渗氮工艺是否合适至关重要。实验以20MnCrS5齿轮钢为试验材料,摸索出电子探针法(EPMA)测定渗氮层的最佳试验参数为:加速电压10 kV,束流100 nA,束斑直径1 μm,步径1 μm。首先,利用电子探针的面扫描功能,对渗氮层从表面到基体进行二维和三维面分布定量化分析,从结果可以看出,表层有一个富集的氮化层,厚度约为10 μm,最高处氮含量(质量分数,下同)达到8.46%,氮化层以内的氮含量在0.84%左右,渗氮层总深度约为600 μm。其次,对比了电子探针线分析法与硬度法的结果,电子探针法测得的渗氮层总深度与硬度法测得的基体硬度值时深度一致,都约为600 μm,且能同时给出不同渗氮层厚度与氮含量的变化曲线。因此,电子探针法作为硬度法的补充方法,可以同时得到准确的渗氮层深度和氮含量,可以作为衡量渗氮工艺是否合适的依据。     

不同渗碳层深度下重载齿轮钢的疲劳性能

 国家工程研究中心, 北京100081;3. 中国钢研科技集团有限公司科技质量部, 北京 100081)     

鞍钢冷轧厂五机架连轧机支承辊的使用与维护

通过对鞍钢冷轧厂五机架冷轧机支承辊服役后辊身表面硬化层出现的硬度变化进行研究,确定出支承辊服役后辊身表面硬化层的深度,从而修改了支承辊磨削制度;又根据支承辊的实际使用寿命,制定了支承辊换辊制度.     

渗碳层厚度及碳含量的表征方法

为了衡量渗碳工艺是否合适,需要对渗碳层的厚度及碳含量进行准确测定。实验探索了一种能够快速准确地表征渗碳层厚度及碳含量的方法,并以18CrNiMo7-6钢为例进行了相关测定。首先,利用化学法验证了电子探针法测定渗碳层的准确性。其次,对比了电子探针法与硬度法的结果,两种方法测定渗碳层厚度的结果一致,电子探针法同时给出了不同渗碳层厚度与碳含量的变化曲线。再次,利用金相法观察了渗碳层及基体的微观组织,由于渗碳层厚度超过了金相法的测定范围,无法做出结果对比。综上所述,电子探针法既可以测定渗碳层的厚度,也可同时得到相应厚度渗碳层的碳含量,是准确表征渗碳层的有效方法,可以作为衡量渗碳工艺是否合适的依据。     

Depth perception in a stereoscopic display as a function of number of stimuli, depth range, and number of scale markers.

Ss were tested on 2 tasks, ranking dots in order of depth and specifying actual depth in space, to determine the effects of number of stimuli, depth range, and number of scale markers on depth discrimination. When ranking was required, increasing the number of dots presented resulted in decreased accuracy. The number of dots did not affect accuracy when specific depth assignments were required. Increasing the number of dots resulted in significantly greater time to complete the task. As depth range was increased, accuracy improved regardless of task and time scores decreased for the ranking task. Decrease in number of scale markers resulted in increased time and error scores. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

热轧中厚板布氏硬度值测定方法

通过对热轧中厚板在不同深度上进行布氏硬度的测定 ,表明测量深度对硬度的明显的影响 ,并指出获得稳定值的必要性。金相观察证实了表面脱碳层的存在是产生硬度值不稳定的原因。     

On the Definition of Microhardness

Microhardness testing can be a very useful tool for studying modern materials, but is plagued by well-known experimental difficulties. Reasons for the unusual behavior of hardness data at very low loads are explored by Monte Carlo simulation. These simulations bear remarkable resemblance to the results of actual hardness experiments. The limit of hardness as load or indentation depth tends to zero is shown to depend on experimental error rather than upon intrinsic material properties. The large scatter of hardness data at very low loads is insured by the accepted definition of hardness. A new definition of hardness is suggested which eliminates much of this scatter and possesses a limit as indentation depth approaches zero. Some simple calculations are used to show the utility of this new approach to hardness testing.     

Substantiation of the ratio of the sample thickness to the indentation depth in hardness measurements

The depths to which plastic deformation occurs under ball indentation of a steel plate at various loads is determined. It is established that the ratio of the depth that plastic deformation reaches to the indentation depth is constant (approximately 15) independently of the indentation load. This finding allows us to conclude that this ratio should be held no less than 15 in hardness measurements. Experiments demonstrate that the lower the hardness of the metal substrate, the larger the decrease in the measured hardness when the ratio is lower than 15.