Subsurface Defect Evaluation of Selective-Laser-Melted Inconel 738LC Alloy Using Eddy Current Testing for Additive/Subtractive Hybrid Manufacturing

Chinese Journal of Mechanical Engineering

Table 3 Coefficients and correlation coefficients of fitting curves in Figure 10(a)

Equation	\(y=\frac{{\mathrm{A}}_{1}-{\mathrm{A}}_{2}}{1+{(x/{\mathrm{x}}_{0})}^{\mathrm{p}}}+{\mathrm{A}}_{2}\)
Defect size (mm)	0.4		0.8		1.2		1.6
Parameter	Value	Error	Value	Error	Value	Error	Value	Error
\({\mathrm{A}}_{1}\)	0.213	0.0046	0.486	0.0063	0.688	0.0093	1.00237	0.0161
\({\mathrm{A}}_{2}\)	− 0.002	0.0162	0.054	0.0180	0.087	0.0250	0.0921	0.0578
\({\mathrm{x}}_{0}\)	0.779	0.0573	0.725	0.0296	0.719	0.0290	0.80069	0.0474
p	2.478	0.3440	2.579	0.2271	2.689	0.0250	2.61041	0.3067
\({\mathrm{R}}^{2}\)	0.994		0.998		0.997		0.996