共查询到18条相似文献,搜索用时 156 毫秒
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通过对火焰切割法取样的热轧Q345B钢板进行拉伸、常温冲击、硬度和金相组织检测试验,得到了距离火焰切割线不同位置试样的力学性能,研究了加工余量对钢板力学性能的影响。结果表明,热轧Q345B钢板距火焰切割线1.5 mm范围内,其显微组织受到了影响;取样加工余量大于5 mm时,钢板力学性能及硬度不受影响。因此,减小火焰切割加工余量可以提高钢板综合成材率。 相似文献
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S40C钢制齿轮服役一段时间后,单个齿面出现裂纹状缺陷。采用宏微观分析、金相检验、显微硬度测试等方法,对该齿轮缺陷产生的原因进行分析。结果表明:齿面裂纹状缺陷为接触疲劳所致,造成局部接触疲劳裂纹产生的根源是齿面存在磨削烧伤,显著降低齿面硬度,改变齿面强度梯度分布,在循环啮合作用下出现接触疲劳开裂。进一步地,对感应淬火齿轮齿面硬度降低的影响因素进行详尽的阐述,并结合不同啮合状态下齿轮强度曲线和剪切应力曲线之间的相互关系,论述常见的齿轮剥落现象及失效机理。 相似文献
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Failure patterns of coated carbide tool were investigated by high-speed face milling of the hardened steel SKD11. Tool failure surface morphology, cutting force and machined surface roughness were also analyzed to reveal the failure mechanisms. The results indicated that the dominant failure pattern of coated carbide tool was breakage. The primary mechanism of tool breakage was fatigue fracture. Under different cutting speeds, the distinctive morphologies of fatigue fracture were presented on the failure surfaces. At low cutting speeds, many fatigue sources were observed on the rake face. The distance between fatigue sources and tool nose was approximately two times of the depth of cut. With the increase of cutting speed, the fatigue striations and riven patterns were observed at the fracture surface. In addition, the fatigue steps and crack deflection were found under high cutting speeds. The main fracture mode was intergranular fracture at lower cutting speeds. However, it was transgranular fracture at higher cutting speeds. Furthermore, the irregular fracture surfaces at low cutting speeds and at high cutting speeds contribute to a larger cutting force increment compared with the medium cutting speeds. The increment of surface roughness in the initial and severe wear stages was lower than that in the steady wear stage, while the deviation of surface roughness was relatively large. 相似文献
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用TC4和TC8钛合金制造的加工刀具,在使用过程中发生失效。利用金相分析、力学性能测试和无损检测等手段对刀具失效的原因进行了分析。结果表明:刀具失效是由刀具开裂引起的。工作过程中刀具表面产生疲劳裂纹,疲劳裂纹在表面不连续缺陷处萌生并扩展。而失效零件粗糙的表面是裂纹产生的主要原因。 相似文献
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某钢厂连铸车间K7043火焰切割机机械系统常见故障表现为提升机构传动箱体断裂;介质系统常见故障表现为管道元器件堵塞、切割枪堵塞;电气系统常见故障表现为编码器故障、电缆损坏、接近开关故障。对切割机常见故障进行分析,表明提升机构传动箱体断裂为箱体存在应力集中造成;管道元器件堵塞为煤气中焦油析出造成,切割枪嘴堵塞为切割热态板坯渣子飞溅堵塞造成;电气系统常见故障多由于切割机工况复杂造成。随后对火焰切割机进行了适应性改造,提升机构传动箱体应力集中现象得到消除,介质系统管路元器件堵塞情况得到改善,缩短了切割枪嘴更换时间,降低了电气元件故障率。对其实际运行情况进行观察,切割机故障率得到明显降低。 相似文献
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Patricia Muñoz-Escalona Maria Carolina Payares Minerva Dorta Ronald Diaz 《Journal of Materials Engineering and Performance》2006,15(6):684-692
Many metal-manufacturing industries include oxyfuel cutting among their manufacturing processes because cutting and welding
are often required in metal-cutting processes, specifically in the fabrication of pressure vessels and storage tanks. The
oxyfuel cutting process uses controlled chemical reactions to remove preheated metal by rapid oxidation in a stream of pure
oxygen. Previous research has demonstrated that metal cutting surfaces varied depending on the gas used for the combustion
as well as the cutting speed (Vc) used during the process. In this research, AISI 1045 carbon steel was cut using an oxyacetylene
and an oxypropane cutting process. Different tests, such as surface roughness, cut drag displacement, groove width, microhardness,
and microstructure, were used to analyze the influence of the Vc and the combustion flame (oxyacetylene and oxypropane). The
results showed, in general, better cut surfaces when using propane gas. Also, it was demonstrated that oxyacetylene cutting
is almost 85% more expensive than oxypropane cutting. 相似文献
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从理论上分析生物柴油用于金属火焰切割的可行性,根据热力学理论计算生物柴油中性焰和氧化焰的理论温度,分析生物柴油燃烧过程中氧气的消耗量;并根据燃烧学对比分析生物柴油与汽油在空气中完全燃烧的火焰长度。计算结果表明:虽然生物柴油火焰温度比乙炔燃烧温度低,但能达到2436℃以上,火焰长度将近是汽油火焰长度的0.92倍,长度基本相当,说明生物柴油可用于金属火焰切割,只是预热时间应比乙炔长。这在理论上说明生物柴油可作为金属切割的燃料,为进一步进行氧生物柴油火焰切割技术研究奠定了理论基础。 相似文献