Studies on pulsed Nd:YAG laser cutting of thick stainless steel in dry air and underwater environment for dismantling applications
Studies on pulsed Nd:YAG laser cutting of thick stainless steel in dry air and underwater environment for dismantling applications
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DOI：
10.1016/j.optlastec.2015.02.007
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发表时间：
2015-08-01
影响因子：
5
通讯作者：
Oak, S. M.
中科院分区：
文献类型：
--
作者：
Choubey, Ambar;Jain, R. K.;Oak, S. M.
旧设备和结构的拆除是核设施和航运业的重要应用。本文介绍了在干燥空气和水下环境中脉冲 Nd:YAG 激光切割厚度在 4-20 mm 范围内的厚不锈钢 (AISI SS304) 板材过程中的工艺优化研究。使用具有光纤光束传输功能的 500 W 平均功率长脉冲 Nd:YAG 激光系统进行了激光切割实验。专门开发了具有同轴气体射流的水保护激光切割喷嘴，用于在水下条件下的切割实验中在激光束周围形成局部干燥腔。研究发现，对于给定的脉冲能量，在脉冲持续时间、光斑重叠和辅助气压的最佳值下，可以实现更高的切割速度。使用氧气作为辅助气体，通过将脉冲持续时间从 14 ms 增加到 20 ms，并将所需光斑重叠值从 80% 减少到 40%，将 20 mm 厚的 SS 样品的切割速度提高到约三倍。对干燥空气和水下环境中的切割速度和热影响区进行了比较。这些结果对于放射性和水下环境中旧钢结构的激光拆除非常有用，与传统拆除方法相比，可以节省时间并最大限度地减少辐射剂量消耗。 (C) 2015 Elsevier Ltd. 保留所有权利。
Dismantling of old equipments and structures is an important application in nuclear facilities and shipping industry. This paper presents a study on process optimization during pulsed Nd:YAG laser cutting of thick stainless steel (AISI SS304) sheets having a thickness in the range of 4-20 mm in dry air and underwater environment. Laser cutting experiments have been performed using a 500 W average power long pulse Nd:YAG laser system with fiber optic beam delivery. A water shielded laser cutting nozzle with coaxial gas jet was specifically developed to form a local dry cavity around the laser beam during the cutting experiments in underwater condition. It was found that for a given pulse energy, a higher cutting speed is possible with optimal value of pulse duration, spot overlapping, and assist gas pressure. Cutting speed of 20 mm thick SS sample was enhanced to about three times by means of increase in pulse duration from 14 ms to 20 ms and reduction in the required spot overlapping from a value of 80% to 40% using oxygen as the assist gas. A comparison of the cutting speed and heat affected zone in dry air and underwater environment has been performed. These results will be highly useful in laser based dismantling of old steel structures in radioactive and underwater environment to save time and minimize radiation dose consumption as compared to conventional dismantling methods. (C) 2015 Elsevier Ltd. All rights reserved.