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以SDC 99模具钢为对象,研究了淬火与回火工艺对其微观组织、硬度和冲击性能的影响。结果表明,经1 040℃淬火和210℃或520℃回火后,SDC 99模具钢的冲击性能和洛氏硬度与进口模具钢相当,且都高于国产Cr12MoV模具钢。 相似文献
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研究了稀土元素Gd和Sc对H13模具钢热疲劳性能的影响。结果表明,在H13模具钢中添加稀土元素Gd或Sc,尤其是复合添加Gd和Sc有利于促进H13模具钢中碳化物的弥散分布、细化组织,提高H13模具钢的热疲劳性能。与未添加稀土元素的H13模具钢相比,复合添加0.25%Gd和0.25%Sc可使其热疲劳级别从13级降为4级,热疲劳性能得到显著改善。 相似文献
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以42CrMo模具钢为研究对象,采用拉伸试验、冲击试验、硬度测试和显微组织分析等方法,研究了淬火温度和回火温度对模具钢组织与力学性能的影响。结果表明,200℃低温回火时,随着淬火温度升高,模具钢的抗拉强度先上升后降低,而伸长率、断面收缩率、冲击韧度呈现下降趋势;600℃高温回火时,随着淬火温度的升高,模具钢的抗拉强度在1 040℃前略有降低,而伸长率、断面收缩率、冲击韧度和硬度整体呈现下降的趋势。200℃低温回火后的模具钢的强度满足要求,但是伸长率和冲击韧度均低于标准要求;600℃高温回火后,模具钢的强度、塑性和韧性都能满足冷作模具钢对基材的要求。 相似文献
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《热处理技术与装备》2016,(1)
正4Cr5MoSiV1是热作模具钢,在碳工钢的基础上加入合金元素形成的合工钢种。合工钢包括:量具刃具用钢、耐冲击工具用钢、冷作模具钢、热作模具钢、无磁模具钢、塑料模具钢。系引进美国的H13空淬硬化热作模具钢。性能和用途与4Cr5MoSiV钢基本相同,但因其钒含量高一些,故中温600℃性能比4Cr5MoSiV钢要 相似文献
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利用扫描电镜和金相分析等对含硼钢铸坯表面典型裂纹进行了观察,结合裂纹产生的机理,从结晶器铜管、二冷区冷却、保护渣理化性能3方面对芜湖新兴10B21含硼钢铸坯表面裂纹的产生进行了分析。分析结果显示,优化结晶器铜管材质和锥度、调整二冷区比水量与分配比以及协调保护渣润滑与传热效果均有利于减少含硼钢铸坯的表面裂纹缺陷。生产实践表明,通过将结晶器铜管由普通镀硬Cr改为Ni-Cr复合电镀,总锥度由优化前2.0%/m降低至1.8%/m;二冷区比水量由0.6 L/kg降至0.5 L/kg,分配比由34∶34∶20∶10∶2调整至31∶26∶20∶13∶10;保护渣黏度由1.358 Pa·s降低至1.169 Pa·s,碱度由0.75提高至0.98。最终铸坯表面裂纹率由原来的最高达17.4%降低至2.3%,同时铸坯表面光滑,振痕较为平整、有规则,轧材的成材率也由原来的86%提高至95%。 相似文献
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K. Narayan Prabhu K. M. Suresha 《Journal of Materials Engineering and Performance》2004,13(5):619-626
Heat transfer during the solidification of an Al-Cu-Si alloy (LM4) and commercial pure tin in single steel, graphite, and
graphite-lined metallic (composite) molds was investigated. Experiments were carried out at three different superheats. In
the case of composite molds, the effect of the thickness of the graphite lining and the outer wall on heat transfer was studied.
Temperatures at known locations inside the mold and casting were used to solve the Fourier heat conduction equation inversely
to yield the casting/mold interfacial heat flux transients. Increased melt superheats and higher thermal conductivity of the
mold material led to an increase in the peak heat flux at the metal/mold interface. Factorial experiments indicated that the
mold material had a significant effect on the peak heat flux at the 5% level of significance. The ratio of graphite lining
to outer steel wall and superheat had a significant effect on the peak heat flux in significance range varying between 5 and
25%. A heat flux model was proposed to estimate the maximum heat flux transients at different superheat levels of 25 to 75
°C for any metal/mold combinations having a thermal diffusivity ratio (α
R) varying between 0.25 and 6.96. The heat flow models could be used to estimate interfacial heat flux transients from the
thermophysical properties of the mold and cast materials and the melt superheat. Metallographic analysis indicated finer microstructures
for castings poured at increased melt superheats and cast in high-thermal diffusivity molds. 相似文献
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Fluid flow, heat transfer and solidification of steel in the mold are so complex but crucial, determining the surface quality of the continuous casting slab. In the current study, a 2D numerical model was established by Fluent software to simulate the fluid flow, heat transfer and solidification of the steel in the mold. The VOF model and k-ε model were applied to simulate the flow field of the three phases(steel, slag and air), and solidification model was used to simulate the solidification process. The phenomena at the meniscus were also explored through interfacial tension between the liquid steel and slag as well as the mold oscillation. The model included a 20 mm thick mold to clarify the heat transfer and the temperature distribution of the mold. The simulation results show that the liquid steel flows as upper backflow and lower backflow in the mold, and that a small circulation forms at the meniscus. The liquid slag flows away from the corner at the meniscus or infiltrates into the gap between the mold and the shell with the mold oscillating at the negative strip stage or at the positive strip stage. The simulated pitch and the depth of oscillation marks approximate to the theoretical pitch and measured depth on the slab. 相似文献
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为应对提高拉速薄板坯结晶器内钢液不稳定行为,以1 520 mm×90 mm薄板坯结晶器为研究对象,利用液面追踪技术VOF方法建模计算,对薄板坯钢渣界面进行了深入研究,实现了对薄板坯连铸结晶器内流体流动及钢/渣界面行为的模拟计算。并结合实际生产工艺,采用1∶1物理模型和数值模拟相互验证,分析了拉坯速度、浸入深度和保护渣黏度种类对结晶器流场及钢渣界面的影响。结果表明,当结晶器钢液面流速为0.20~0.25 m/s,且界面较平稳时,保护渣黏度高于0.237 Pa·s可以适用;当钢液流速为0.25~0.30 m/s,保护渣黏度为0.382 Pa·s时,现场低碳钢卷渣率小于0.5%,表现出良好的抗卷渣能力。 相似文献
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模具材料是决定模具性能和寿命的重要因素之一.叙述了对塑料模具用钢材料的性能要求和钢材的种类及选择,介绍了一些新型塑料模具用钢的成分、热处理和性能特点,说明了它们在不同类型模具中的应用范围,并对今后的发展进行了展望. 相似文献
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张元好 《特种铸造及有色合金》2003,(1):61-63
试验测得消失模铸造空心凸轮轴充型过程的温度场,对其热量分布进行了计算,计算结果表明,金属流充型过程中热量主要损失于使砂型和钢管加热,采用薄壁钢管,提高浇注温度可以解决空心凸轮轴浇不足缺陷,与试验验证结果一致。 相似文献