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焊接裂纹应力与磁记忆信号关系的实验研究 总被引:1,自引:0,他引:1
焊接裂纹产生的应力集中区是焊接构件在服役过程中最为危险的一个薄弱环节,对这个环节进行有效的安全评估,具有重要意义。金属磁记忆技术是近年来发展的一种全新的无损检测方法,它可以在地磁环境下检测铁磁构件的应力集中,从而诊断出产生(或可能产生)裂纹的危险区域。利用磁场中的高斯方程,对管线钢焊接裂纹的应力和金属磁记忆信号之间的关系模型进行了初步探讨,然后利用预制的焊接裂纹对此关系模型进行了研究预测,分析结果表明:此关系模型可满足应力检测的精度要求。 相似文献
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The effect of Y-base rare earth alloy in ultra-high hardfacing was observed by means of OM, SEM and XRD. Precipitated carbide can be metamorphosed and spheroidized in surfacing by adding Y-base rare earth alloy, which contributes to the increase of precipitated carbide. Rare earth combined with oxygen and sulfur can improve the morphology of slag inclusion as well as purify surfacing. The result shows proper rare earth alloy in surfacing can fine its microstmcture, improve hardness and impact toughness. 相似文献
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The arc spraying process is divided into two stages:the first stage is atomization-spraying stream (ASS) and the second one is spraying deposition (SD). Then study status is described of both stages‘ physical model and corresponding controlling-equation. Based on the analysis of study status, the conclusion as follows is got. The heat and mass transfer models with two or three dimensions in ASS stage should be established to far deeply analyses the dynamical and thermal behavior of the overheat droplet. The statistics law of overheated droplets should be further studied by connecting simulation with experiments. More proper validation experiments should be designed for flattening simulation to modify the models in SD stage. 相似文献
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回顾总结了液化天然气低温储罐用9%Ni钢的研究和发展,对9%Ni钢的显微组织结构、力学性能以及现场焊接性进行了介绍.使用最普遍的淬火 回火态9%Ni钢的组织形态主要为回火马氏体,并分布有少量残余奥氏体.9%Ni钢具有很高的强度和良好的低温韧性,焊接性良好,冷裂敏感性较低,采用合适的焊接工艺措施,可防止热裂纹的出现,获得具有良好低温韧性的焊接接头.9%Ni钢焊接时,焊接热输入一般控制在7~35 kJ/cm,多层焊层间温度应控制在100℃以下. 相似文献
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利用DZ-1400型电火花沉积/堆焊机,以工业纯钛TA2为电极,以工业纯氮为保护气和反应气,在TCA钛合金试件表面上制备了TiN/Ti复合涂层。利用X射线衍射仪分析了放电电容、输出电压、脉冲频率对涂层物相的影响,利用MH-6型显微硬度计测定涂层断面不同区域的显微硬度,利用KYKY2800扫描电镜观察涂层组织结构和磨损形貌,采用MS-T3000型球盘式摩擦磨损试验仪测试涂层的摩擦系数和磨损失重。结果表明,涂层中物相种类随放电电容、输出电压、脉冲频率的不同而变化。涂层组织致密,与基体之间形成冶金结合,涂层显微硬度呈梯度变化,涂层摩擦系数小,耐磨性好。 相似文献
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采用热模拟技术研究了热输入和层间温度对9%Ni钢焊接热影响区中四个亚区域低温韧性的影响,并利用光学显微镜、X射线衍射仪对各亚区域的组织形态和数量分布进行了观察分析。结果表明,临界热影响区低温韧性对热输入和层问温度的变化不敏感;层间温度是影响粗晶区低温韧性的主要工艺参数;热输入则是影响过临界粗晶区和临界粗晶区低温韧性的主要工艺参数。热输入越大,晶粒和组织越粗大,低温韧性恶化;层间温度提高,马氏体的自回火作用越显著,低温韧性改善。因此,焊接9%Ni钢时,应采用较小的焊接热输入,配合较高的层间温度。 相似文献
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Effect of oxygen-containing additives on weld penetration in self-shielded flux cored arc welding 下载免费PDF全文
The effect of Fe2O3 and Li2CO3 additives in flux core on the weld metal oxygen content and weld penetration in self-shielded flux cored arc welding were studied schematically. The result shows that the oxygen content in the weld metal and weld penetration both increased with the Fe2O3 addition increased in the range of 5wt.% to 20wt.% . The oxygen content in the weld metal was increased with the Li2CO3 addition increased in the range of 1wt.% to 8 wt.%. However, the weld penetration decreased when Li2CO3 addition exceeding 4 wt.%. High-speed photographic images show that when Fe2O3 addition in flux core exceeding 15wt.%, droplet became excessively large, so that spatters were frequently generated in large numbers. In this study, Fe2O3 and Li2CO3 in the amount of 11wt.% and 4wt.%, respectively, jointly added in the flux core can achieve a deeper weld penetration with sound usability characteristics. 相似文献