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排序方式: 共有188条查询结果,搜索用时 15 毫秒
1.
基于焊接温度场正面信息的熔透控制方法及验证 总被引:3,自引:1,他引:2
在所建立的试件有限尺寸三维温度场解析模型的基础上,利用相关性原理同时考虑温度变化的灵敏度问题,定量地给出了控制背面熔宽时正面测温点的选择区域,提供了测温点的一般选择原则,讨论了基于温度场正面信息的GTAW熔透控制方法,运用仿真手段进行了PID参数优化设计,通过试验验证了PID和FUZZY复合控制的有效性。 相似文献
2.
药芯焊丝气体保护焊在高压Cr-Mo钢管上的应用 总被引:1,自引:0,他引:1
采用钨极惰性气体保护焊(GTAW)打底与药芯焊丝气体保护焊(FCAW)填充、盖面的焊接方法对ASME SA-335 P22和ASME SA-335 P11钢管做了焊接工艺评定。分别对其焊缝进行了拉伸、弯曲、冲击和硬度检测等力学性能试验,并通过金相照片对焊缝的微观组织进行了分析,结果证明工艺评定焊缝的各项力学性能指标都达到了ASME Ⅸ的要求,该焊接方法在实际生产中是可行的。 相似文献
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In this paper, in situ synthesized TiC particles reinforced Fe-based surface composite coatings by multi-pass overlapping gas tungsten arc welding (GTAW) melting process employing a proper amount of graphite and ferrotitanium (FeTi) on AISI 1020 steel substrate was produced. The microstructure and wear properties of the composite coatings were investigated by means of an electron microprobe microanalysis (EPMA), X-ray diffractometer and wear tester. The results showed that the multi-pass overlapping GTAW melting surface composite coatings can be obtained under suitable welding parameters, and no crack and porosity are found in the tracks. The X-ray and EPMA results confirm that TiC particles can be formed via reaction of FeTi and graphite during multi-pass overlapping GTAW melting process. TiC particles present cubic and dendrite shape in the non-overlapping zone. It is found that there occurred TiC particles coarsening at the overlap regions, which can lead to detrimental effects on the hardness and wear performance. Composite coatings give a high hardness and excellent wear resistance; and the wear friction coefficient of the coating is less than that of the 1020 steel. As a result, multi-pass overlapping GTAW melting process can be used effectively for producing surface composite coatings with a pre-placed powder to improve wear resistance of the AISI 1020 steel. 相似文献
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《Energy Materials: Materials Science and Engineering for Energy Systems》2013,8(4):1184-1190
AbstractDegradation of AISI 410 martensitic stainless steel, a typical alloy for many applications such as steam turbine blade, could impair its efficiency and lifetime. To overcome this problem, critical surfaces could be modified by weld cladding via gas tungsten arc welding technique. In the present research, a comparative study of Stellite 21 weld overlays deposited in three different thicknesses, i.e. dilutions, at various preheat and post-weld heat treatment temperatures on the surface of AISI 410 martensitic stainless steel, has been made. The surface of coatings has been examined to reveal their microstructures, phase characterisation and mechanical properties using XRD, microhardness tester and metallographic techniques. The results showed that the deposition of Stellite 21 coating on AISI 410 martensitic stainless steel improved its corrosion resistance. Moreover, the volumetric dilution had a considerable effect on the hardness, microstructure and electrochemical corrosion behaviour of Stellite 21 weld overlays. 相似文献
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A study of port plug distortion resulting from narrow gap combined GTAW & SMAW and Electron Beam Welding was carried out. Thermomechanical finite element analysis of port plug becomes virtually impossible because of the requirement of huge number of nodes and elements. Hence an analysis method based on the concept of inherent strain was used in this work. The computational time required was about 40-50 min only in a Core (TM) 2 Duo, 2.66 GHz computer with 2 GB RAM, which otherwise was not possible with other conventional computation techniques. As was expected the overall distortion due to EB welding was found to be less compared to that of narrow gap GTAW & SMAW. 相似文献
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A comparison has been made of the relationship between microstructure and microhardness developed by surface melting Nanosteel SHS 7170 Fe–Cr–B alloy powder onto a plain carbon steel surface. This powder was initially developed as a high velocity oxyfuel sprayed coating, giving a strength 10 times that of mild steel, and is particularly suitable for surface protection against wear and corrosion. In the present study, the alloy powder was injected into the laser melted surface, while a preplaced powder was melted using the gas tungsten arc welding (GTAW) technique. The laser track consisted of fine dendrites and needle-like microstructures, which produced a maximum hardness value of over 800 HV, while the GTAW track produced a mixture of equiaxed and columnar grain microstructures with a maximum hardness value of 670 HV. The lower hardness values are considered to be associated with dilution and grain size. 相似文献