共查询到19条相似文献,搜索用时 134 毫秒
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对原油储罐用国产12MnNiVR钢板焊接接头进行了空气和储罐污水中的疲劳裂纹扩展试验。通过七点增量递增多项式局部拟合求导的方法,对试验过程中记录的各组数据进行处理,得到12MnNiVR钢板焊接接头在空气及原油储罐污水中的疲劳裂纹扩展特性。并用Paris公式对试验数据进行回归处理,得出其疲劳裂纹扩展速率方程。试验结果表明,石油储罐的污水溶液对12MnNiVR钢焊接接头疲劳裂纹扩展速率没有显著影响。 相似文献
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44—50mm厚CF—62钢焊接冷裂纹敏感性评定 总被引:1,自引:1,他引:1
本文通过插销冷裂纹试验(定量试验),小铁研试验,窗形枸束裂纹试验及焊接热影响区最高硬度法试验等方法,对44-50mm厚CF-62钢焊接冷裂纹敏感性进行综合评定,认为该钢抗冷裂性良好。并结合大型球罐的特点,提出防止冷裂纹产生的控制要点。 相似文献
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对 2 2 5Cr - 1Mo - 0 2 5V钢采取 5种焊接性试验方法 ,确定了该钢不产生冷裂纹的工艺所需预热温度 ,同时也论及了该钢的再热裂纹倾向。试验表明 ,2 2 5Cr - 1Mo - 0 2 5V钢具有较优良的焊接性能。 相似文献
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对德国钢材15Mo3进行了斜y型坡口焊接裂纹试验、再热裂纹试验及层状撕裂等金属焊接性试验;制定了适合于这种进口钢材的焊接工艺;分析研究了15Mo3耐热钢的焊接性。结果表明,15Mo3耐热钢冷裂倾向和再热裂纹倾向较小,层状撕裂倾向较大。 相似文献
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用刚性对接裂纹试验方法研究了12MnCrNi钢的焊接裂纹,并用扫描电镜和能谱分析了产生裂纹的原因。结果表明,焊接裂纹率与焊接线能量有关,焊接裂纹起源于近缝区母材晶间熔化处,扩散氢的聚集促进液化裂纹扩展、联接,因此,刚性对接裂纹试验中的裂纹属于热、冷混合裂纹。 相似文献
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国产508—Ⅲ钢焊接性试验研究 总被引:2,自引:0,他引:2
本文选用了斜Y型坡口冷裂试验,可调拘束热裂纹试验和热影响区最高硬度法等几种典型的焊接性试验方法,对国产508—Ⅲ钢进行了焊接性试验研究。试验结果表明,国产508—Ⅲ钢有很好的抗裂性,适合于核电站反应堆压力容器的制造应用。 相似文献
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本文通过对引进球罐用钢的焊接热影响区最高硬度试验和斜Y型坡口裂纹试验,证实了引进球罐用18G_2ANb钢的冷裂纹敏感性较高。本文还提出了防止焊接裂纹的相应工艺措施。 相似文献
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为验证ASTM A517锻件钢板是否适于焊接加工,必须按照一定的要求进行焊接性试验,例如:斜Y型坡口焊接裂纹试验、T型接头焊接裂纹试验、焊接热影响区最高硬度试验、平焊位对接焊焊接试验等、各试验项目必须要有明确的试验目的. 相似文献
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S. Manimozhi S. Suresh V. Muthupandi 《The International Journal of Advanced Manufacturing Technology》2010,51(1-4):217-223
Advanced creep-resistant steels have been developed to meet the demanding requirements of fossil power plants that strive to improve the generation efficiency by enhancing the steam temperature and pressure. These are ferritic steels with nominal chromium content ranging from 2% to 12% with significant addition of tungsten besides Nb, V, and N in small level. One of the candidate materials is 9Cr-0.5Mo-1.7W steel, developed for steam circuit components of tubes, and pipes of power plants for an operating temperature of 600°C. Hydrogen cracking is a major issue in welding of this steel, due to solid-state metallurgical transformations that lead to untempered martensite in the HAZ of weld joint. The hydrogen cracking does not occur below a threshold stress level called critical cracking stress. The critical stress for cracking in this steel was determined by carrying out implant weldability tests using shielded metal arc welding process for various levels of diffusible hydrogen in the weld metal and an empirical model relating levels of diffusible hydrogen and time taken for cooling from 800°C to 500°C to the critical stress has been developed. Results of current study also showed that residual diffusible hydrogen plays a major role in deciding hydrogen cracking than the initial diffusible hydrogen in the weld metal. 相似文献
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通过对开裂的高压蒸汽管线断口进行宏观分析、金相显微组织分析、显微硬度测试、力学性能测试和微观断口形貌分析.找出管线在该区发生开裂失效的主要原因是焊接接头过热区珠光体完全球化;焊接接头过热区在焊接冷却过程中出现的部分淬火马氏体(淬火硬化)促进了该区珠光体的球化过程。提出将蒸汽管线三通材料由现有20号钢改为15CrMo钢,降低含碳量,以降低管线珠光体球化速度,提高管线高温持久寿命;同时严格控制高压蒸汽压力和并网温度,避免高压蒸汽压力和温度较大波动;监控高压炉水质和高压蒸汽品质;稳定加热炉运行等措施。 相似文献
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A new thermal error modeling method for CNC machine tools 总被引:2,自引:2,他引:0
Jian Han Liping Wang Haitong Wang Ningbo Cheng 《The International Journal of Advanced Manufacturing Technology》2012,61(1-4):205-212
Shape memory superelastic alloys as NiTi have mechanical properties and biocompatibility characteristics quite interesting for a set of industries, amongst which is the medical industry. They find applications in tools and devices where frequently joining between them and to other alloys as austenitic stainless steel is required. However, permanent joining of NiTi to stainless steel is problematic due to the formation of Fe–Ti intermetallics. Pulsed laser welding was studied to join thin foils of NiTi in similar and dissimilar joints to stainless steel. Joining NiTi to NiTi was succeeded with no weld defects. When joining NiTi to stainless steel, it was found that the material impinged by the laser determined the weld pool shape and structure, and it was better when the stainless steel foil was placed below the laser, because nickel enrichment of the weld pool was found to minimise cracking. The factors controlling the weld pool composition and, consequently, the quality of the weld were investigated and discussed. 相似文献
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根据刚性拘束裂纹试验机理,自主研制了国内首台大吨位高强钢刚性拘束焊接冷裂纹倾向试验装置,其具有精准的测量系统,完全适应48 h的拘束应力维持时间,该机可提供最大1 200 kN的试验力。利用该冷裂试验装置进行E36钢板对接接头刚性拘束裂纹试验,对比分析GFL-71NI焊丝(国产)和DW-A55L焊丝(进口)的冷裂纹敏感性。结果表明,通过药芯焊丝气体保护焊接方法施焊,采用GFL-71NI焊丝获得接头的临界拘束距离大于DW-A55L焊丝接头,经计算GFL-71NI焊丝接头的临界拘束度和临界拘束应力均小于DW-A55L焊丝接头,最终得到GFL-71NI焊丝接头的冷裂敏感系数高于DW-A55L焊丝接头,数值分别为0.345 147和0.326 094,表明DW-A55L焊丝的抗冷裂性能优于GFL-71NI焊丝。金相分析显示,与GFL-71NI焊丝接头相比,DW-A55L焊丝接头焊缝组织更均匀,晶界铁素体含量明显减少;过热区组织中的淬硬组织含量也较少,这显著降低了DW-A55L焊丝接头的冷裂倾向。 相似文献
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对30CrMo和40CrNi钢埋弧自动焊焊缝金属的强韧化进行了初步研究。结果表明控制好焊缝金属的合金化程度,能细化针状铁素体,阻止M-A组元脆化、使焊缝金属达到良好的强韧性配合,并且能有效地防止焊拉结晶是裂纹的生产。 相似文献