共查询到19条相似文献,搜索用时 140 毫秒
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研究了喷射成形S390高速钢组织和性能,结果表明:喷射成形S390高速钢沉积坯具有低的氧含量,仅为18ppm,组织无宏观偏析,主要有M6C和MC两种碳化物相,碳化物呈均匀弥散分布在晶界和晶内。经过热处理后,喷射成形S390合金的抗弯强度可达4044MPa,合金硬度随淬火温度呈上升趋势,在1250℃淬火后,硬度达到了HRC69.3。 相似文献
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喷射成形是一种基于快速凝固技术的高温合金、高性能材料制备工艺,对喷射成形过程中沉积锭坯的轮廓及其形状特征进行实时、准确地检测是实现喷射成形工艺稳定性控制的关键。基于机器视觉技术研究了喷射成形锭坯轮廓在线检测方法,设计了视觉检测系统结构,对喷射成形生产环境下的锭坯轮廓图像处理算法进行了研究,提出了锭坯轮廓特征提取方法。实验和测试表明,轮廓及直径、喷射高度的检测精度可达1 mm,算法平均运行时间为0.83 s,可以长时间稳定地在线检测沉积锭坯的轮廓。 相似文献
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严必玲 《机械工人(热加工)》1984,(10)
高速钢系高碳、高合金钢,它具有导热性差、塑性低、碳化物偏析严重、易氧化脱碳以及过热过烧倾向性大等特性。为了保证高速钢刀具锻坯的质量,除了采取正确的改锻工艺之外,掌握合理的加热方法是一个很重要的因素。一、高速钢一般加热规范各工厂经过长期生产实践的经验总结,对于高速钢,根据不同化学成分,在加热规范上已作出具体规定。在保证不过热的原则下,利用其高温状态 相似文献
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<正> 碳化物不均匀性是高速钢的重要特征。要保证复杂刀具的标准耐用度,如加工高碳钢和合金的螺纹成形铣刀,其碳化物不均匀性不得超过2~3级。但在供售状态下的高速钢,只有直径为20~40毫米的小圆片才能满足这样的要求。直径为80~100毫米的棒料,其碳化物不均匀性达6~7级。为降低碳化物不均匀性等级,基本上采用自由锻造,但不能经常达到理想的效果。采取等温形变方法可使高速钢的塑性得以显著地提高。在压力机的一 相似文献
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《机械工人(热加工)》1999,(3)
由大连铁道学院研制开发的无莱氏体高速钢不同于低碳莱氏体高速钢和国内外曾研制的渗碳高速钢。新型无莱氏体高速钢的锻、轧、冷拔性能优于普通高速钢,经专门为其研制的三低一高工艺处理后所得组织及性能与粉末高速钢相当,其特色在于不存在碳化物偏析及粗大碳化物,而且碳饱和度可 相似文献
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The effect of billets extruded by a curved and flat-face die on the semisolid characteristics and tensile properties of thixoformed products 总被引:1,自引:1,他引:0
Amir Bolouri Yong Phil Jeon Chung Gil Kang 《The International Journal of Advanced Manufacturing Technology》2014,70(9-12):2139-2149
In this study, A356 aluminum billets in different extruded states are used as feedstock for the thixoforming. The extrusion billets were fabricated by a hot extrusion process through a flat-face and a curved die. After the induction reheating of the extrusion billets into a semisolid state, the microstructural evolution was thoroughly investigated. For the extrusion alloy by the flat-face die, there was a large variation in the average grain size (20 %) and the mean roundness (17 %) of equiaxed α-Al grains. This, together with evidence of elongated grains in the interior regions of the billet, indicated that a noticeably nonuniform globular microstructure had been obtained. In contrast, for the extrusion alloy through the curved die, the obtained globular microstructure was more uniform. There were slight variations of 5 % and 7 % in the average grain size and the mean roundness, respectively. By using the extrusion billets, some parts fabricated via the thixoforming process those underwent T6 heat treatment. The tensile test results for the fabricated parts showed that when the extrusion billet through the conventional flat-face die was used as the feedstock, there was a large scattering in the tensile properties throughout the part. In contrast, when the extruded billet through the curved die was used as the feedstock, limited variation was observed in the tensile properties. 相似文献
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V. V. Stulov 《Journal of Machinery Manufacture and Reliability》2011,40(1):59-62
The results of a steel cooling simulation in the process of obtaining hollow billets using a finned heat pipe as the core
model after heating by an electric heating element are presented. The novelty is confirmed by patents for techniques of obtaining
hollow billets and crystallization tank cooling using a heat pipe. Heat power values passed within a heat pipe model and high-temperature
pipe in the process of steel cooling are found, and a heat-carrying medium mass in high-temperature pipe and its sizes are
determined, along with the cast steel temperature and parameters of the heat-carrying media. 相似文献
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针对带法兰盘阶梯轴的结构特点,提出了镦挤复合成形工艺方案,并分别研究了在冷镦挤条件下,不同直径坯料对成形过程的影响.采用有限元模拟软件对带法兰盘阶梯轴的成形过程进行了数值模拟,比较分析了不同坯料尺寸对变形过程中金属流动、应变以及载荷曲线等的影响.试验结果表明,采用冷镦挤复合成形工艺成形带法兰盘阶梯轴,可以获得高质量和高精度的锻件,实现近净成形. 相似文献