共查询到19条相似文献,搜索用时 312 毫秒
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利用G90-SAT红外热像仪测量了玻璃模具喷焊时的温度分布。结果表明,无论是同一点不同时刻的温度还是同一时刻不同截面的温度变化均十分复杂,工件表面每一点的温度都遵循低!高!最高!高!低的变化规律,喷焊重熔时温度最高。热喷焊是一个快速加热、快速冷却的过程,喷焊过程中,玻璃模具表面的温度存在着不均匀性及不同时性。 相似文献
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等离子喷焊过程中熔池温度波动大,目前主要存在依赖人工干预、自动化程度低等问题,喷焊层质量受到很大影响。因此,喷焊过程熔池温度的实时控制是等离子喷焊技术发展的必然选择。为研究喷焊过程熔池温度变化对喷焊层组织性能的影响,开发实时监控技术打下基础,采用在线监测的方法,对喷焊过程熔池温度进行实时测量,分析了喷焊过程熔池温度对喷焊层宏观形貌、组织成分和显微硬度的影响。结果表明,等离子喷焊过程熔池温度控制在1400℃左右,喷焊层具有较好的组织与性能。喷焊过程熔池温度较低时,容易引起近熔合区形成氧化物夹杂;喷焊过程熔池温度过高时,容易造成喷焊层稀释率的增加。喷焊电流110 A时,前段喷焊层的显微硬度为(670±26) HV0.1,明显高于中段喷焊层的显微硬度(550±20) HV0.1;当喷焊电流为70、110和150 A时,喷焊层显微硬度呈由高到低的趋势。 相似文献
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在5CrNiMo切边模的刃口或终锻模的型腔表面,采用氧乙炔焰喷焊粉102或粉204硬质合金粉末,制作与修复的热作模具,其喷焊层表面的硬度可达HRC58~64,延长了热作模具的使用寿命,经济效果显著。本文介绍了热作模具的喷焊工艺。 相似文献
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45钢瓷砖模具表面喷焊强化处理 总被引:1,自引:0,他引:1
为提高瓷砖模具的耐磨性和节省原材料,试验研究了45钢表面喷焊覆层强化处理与Cr12MoV钢制模具的抗磨料磨损性能;测试了喷焊覆层与45钢基体的结合强度和焊层的显微组织结构及各组成相的显微硬度,为采用45钢表面喷焊覆层处理替代Cr12MoV模具钢制造瓷砖模具提供了可靠的保证。 相似文献
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生产某壳体零件的模具存在严重的冷热疲劳早期失效现象,结合生产实际利用Deform有限元模拟软件对其温挤压过程进行模拟。通过对比模拟分析可得到凸模在工作时不同时刻的温度值,不同模具预热温度和坯料温度下模具的最高温度分布以及急冷急热温度差范围。为了减缓模具的冷热疲劳,模具预热温度最好控制在200~300℃之间,坯料加热温度控制在800℃内。 相似文献
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将试验与有限元数值分析相结合,建立了某飞机起落架模具模型。采用弹塑性有限元方法模拟了坯料锻造成形过程,并分析了不同时刻模具温度场和应力场。结果表明,随时间增加,模具应力及温度均上升,模具充满时达到最大值,等效应力最大值出现在模具桥部圆角处,并且应力与温度随与该位置距离的增加而减小。分析坯料填充饱满时参考线位置的状态,结合实验得到铸钢基体、过渡层、表面层材料随温度变化的压缩屈服强度曲线,综合考虑各焊层厚度对模具性能的影响及控制模具制造成本等因素,设计在该工况条件下铸钢基体双金属梯度层总厚度为16 mm,其中表面强化层和过渡层的最优厚度均为8 mm。 相似文献
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水平连铸结晶器动态热流分布的实验研究 总被引:1,自引:1,他引:0
采用在结晶器壁内埋置热电偶的方法,对水平连铸结晶器在连铸时的动态热流密度分布进行了测试。经过对测试结果数据处理,得出了热流密度分布表达式和结晶器壁的温度场。 相似文献
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Xuemei Liu Junshan Yao Xinhong Wang Zengda Zou Shiyao Qu 《Journal of Materials Processing Technology》2009,209(3):1392-1399
Friction surfacing is an advanced process of great potential, especially in the field of repair and reclamation of worn and damaged components. The temperature field of consumable-rod in friction surfacing, as a kind of thermal processing technology, is an important factor in the successful implementation of the process. In this paper, the heat source model of consumable-rod in friction surfacing is established, by which the temperature field of consumable-rod during the process is simulated through finite difference method. The results are consistent with experiments, reappearing the temperature field of consumable-rod during friction surfacing, thus providing theoretical guidance in the choice for key technical parameters in engineering practice. 相似文献
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《中国铸造》2016,(5):327-334
A three-dimensional finite-element model has been established to investigate the thermal behavior of the medium-thick slab copper casting mold with different cooling water slot designs. The mold wall temperatures measured using thermocouples buried in different positions of the mold with the original designed cooling system were analyzed to determine the corresponding heat flux profile. This profile was then used for simulation to predict the temperature distribution and the thermal stress distribution of the molds. The predicted temperatures during operation matched the plant measurements. The results showed that the maximum temperature, about 635 K in the wide hot surface, was found about 60 mm below the meniscus and 226 mm from the center of the mold. For the mold with the type I modified design, there was an insignificant decrease in temperature of about 5 K, and for the mold with the type II modified design, the maximum temperature was decreased by about 15 K and the temperature of the hot surface was distributed more uniformly along the length of the mold. The corresponding maximum thermal stress at the hot surface of the mold was reduced from 408 MPa to 386 MPa with the type II modified design. The results indicated that the modified design II is beneficial to the increase of mold life and the quality of casting slabs. 相似文献
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Tae-Jin JE Eun-Chae JEON Sang-Cheon PARK Doo-Sun CHOI Kyung-Hyun WHANG Myung-Chang KANG 《中国有色金属学会会刊》2011
Micro prism film used in LCD industry can be manufactured by roll to roll method with copper-plated roll mold. As copper-plated roll mold is getting larger, pitch error is getting severer. The pitch error drops the quality of micro prism film. The main cause of the pitch error was investigated during machining large roll mold whose machined length was 1 200 mm. The temperature of machining system was elevated during machining roll mold, and this elevation induced thermal expansion of the system. The temperature variation around the roll mold also made thermal expansion of the roll mold. The amount of thermal expansion had strong relationship to the amount of pitch error. Therefore, the roll mold was machined after warming-up of machining system and precise temperature controller around copper-plated roll mold was installed, which minimized the temperature variation. Finally, precise micro prism patterns without pitch error were machined on the large roll mold. 相似文献
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用电渣堆焊的方法在D32低合金钢表面堆焊高铬铸铁硬面层,测量了堆焊过程中热影响区的温度场,研究了热影响区、复合界面及硬面层的微观组织和力学性能.结果表明,电渣堆焊加热和冷却速度较慢,稳定阶段时低合金钢基材温度分布均匀,在堆焊方向最大温度梯度为-21.25℃/mm;低合金钢基板内最大热应力为53.4 MPa,低于低合金钢的抗拉强度,有效避免了裂纹的产生;复合界面平整清晰,存在宽度约50μm的奥氏体带状区;热影响区晶粒有所长大,为铁素体加珠光体组织;高铬铸铁硬面层由奥氏体、碳化物和少量马氏体组成,M7C3型碳化物细小且均匀分布于奥氏体晶界;复合界面结合强度为96 MPa;试样熔合区的冲击吸收能量(53 J)较硬面层冲击吸收能量(10.7 J)明显提高;亚共晶高铬铸铁硬面层在较大磨损载荷下发生马氏体相变,硬度提高,耐磨粒磨损性能优良. 相似文献
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随着国内高拉速连铸机日渐增多,结晶器铜板的失效已经变为以热疲劳裂纹形式为主。采用ANSYS数值模拟软件对结晶器铜板温度和热流密度分布规律进行了研究。计算结果表明,结晶器铜板的温度分布和生产中热疲劳裂纹的形式不相同;铜板弯月面区发生热裂失效的主要原因是在一定温度下,上下运动的热流密度的集中区即“能量流”撕裂了铜板,因此减小结晶器铜板弯月面处的热流密度,有可能减少铜板热裂纹的产生。设计均匀传热、减少铜板和连铸坯裂纹生成的结晶器是未来技术发展的方向。计算结果表明,沟槽结晶器铜板表面刻划沟槽后可以减弱弯月面区域热流密度,改善结晶器铜板的不均匀传热状况。 相似文献