Continuous Scanning Technique with Barkhausen Magnetic Noise for Carbon Steel Sheets

This work studies the application of a Non-Destructive Inspection Technique (NDIT), based on the Magnetic Barkhausen Noise (MBN), for the detection of non-homogeneous regions in carbon steel plates. It presents the advances in the development of a variant of a new non-destructive magnetic test technique, called Continuous Scanning Magnetic Barkhausen Noise (CSMBN). The non-homogeneous or damaged regions were produced by plastic deformations in rolled and annealed sheets of SAE 1060 and 1070 steels. MBN is generated by abrupt changes in the magnetization of materials when subjected to alteration. The sensitivity of the MBN signals in the detection of plastic deformations was analyzed varying parameters such as excitation magnetic field frequency and the speed of movement of the probe. The behavior of the root mean square of magnetic Barkhausen Noise signal (RMSMBN) parameter was correlated with the position of the nonhomogeneous regions detected in the samples. An evaluation of the technique applied to the measurement was made, comparing the results obtained with the Static Magnetic Barkhausen Noise (SMBN) technique, which is a method already established in the literature. The results showed that in all cases studied it was possible to detect the position of the damage, due to variation of the magnetic field. These changes are affected by the presence and distribution of elastic stresses (compression and traction), plastic deformation and microstructure modification. The results of CSMBN were similar to the SBMN with the advantage of being a continuous and more productive procedure. This new technique increases the spectrum of NDIT solutions for problems not contemplated by existing techniques.

本研究探讨了基于巴克豪森磁噪声（Magnetic Barkhausen Noise, MBN）的无损检测技术（Non-Destructive Inspection Technique, NDIT）在碳素钢板非均质区域检测中的应用。本文阐述了一种新型非破坏性磁检测技术变体的研发进展，该技术被命名为连续扫描式巴克豪森磁噪声（Continuous Scanning Magnetic Barkhausen Noise, CSMBN）。研究中的非均质或损伤区域，通过对SAE 1060与1070钢的轧制退火板材施加塑性变形制备得到。巴克豪森磁噪声源于材料受磁化作用时发生的磁化突变现象。本研究通过调整励磁磁场频率、检测探头移动速度等参数，分析了MBN信号对塑性变形的检测灵敏度。将巴克豪森磁噪声信号均方根值（RMSMBN）参数的变化规律，与试样中检测到的非均质区域位置进行了关联。对该技术的实测效果开展了评估，并将所得结果与文献中已成熟应用的静态巴克豪森磁噪声（Static Magnetic Barkhausen Noise, SMBN）技术进行对比。结果表明，在所有研究工况下，均可通过磁场变化实现损伤位置的检测。此类磁场变化受弹性应力（压应力与拉应力）的存在与分布、塑性变形以及微观组织改性的影响。连续扫描式巴克豪森磁噪声的检测结果与静态巴克豪森磁噪声相近，其优势在于可实现连续检测且检测效率更高。该新技术拓展了无损检测技术的应用范畴，可解决现有技术尚未覆盖的检测难题。