不锈钢碳钢层合板经激光快速加热弯曲后，弯折区出现增厚现象。借助IPP图像处理软件测量各层厚度及碳钢层晶粒尺寸，基于温度梯度机理分析弯折区增厚机理及规律。研究结果表明：不锈钢层合板在加热过程中晶粒生长，尺寸增大，产生热膨胀增厚；正向弯曲过程中，晶粒在弯曲应力作用下挤压伸长，产生挤压增厚，在二者的共同作用下，板材厚度增加，且热膨胀增厚占主导地位。增厚现象主要出现在上层不锈钢及碳钢层，碳钢层增厚值所占比重大于69%。最后，研究功率、扫描速度、扫描次数、离焦量等能量参数对增厚值的影响规律，为提高激光弯曲精度与质量提供理论和实验依据。

The bending zone thickening of the metal sheet becomes bigger after laser bending. IPP image processing software is the measure tool of the thickness and the grain size. Then rely on temperature gradient mechanism (TGM) to research the thickening mechanism. The results show that the grain size becomes bigger in the heating process which means thermal expansion thickening (TET). In the positive bending process grains are squeezed and extended by the bending stress and forming extrusion thickening (ET). TET and ET are the principal factors of thickening appearance, and TET occupies the main position. The stainless steel layer and the carbon layer become thicker, and the thickened value of the carbon layer at least account for 69%. At last, the relation between the energy parameters (ie. power, scanning speed, scanning frequency and defocusing amount) and the thickened value is studied, which are the basis of theory and experiment for better bending mould and quality.