Variations in surface residual compressive stress and magnetic induction intensity of 304 stainless steel

• Micro-magnetic method for detecting surface residual compressive stress.
• The material of specimen was 304 stainless steel.
• The micro-magnetic detection was based on the geomagnetic field.

This study proposed micromagnetic nondestructive detection technology to detect the surface residual compressive stress of 304 stainless steel specimens after annealing treatment and loading. X-ray diffraction was used to determine the changes in residual compressive stress, microstrain, and grain size to aid in verification. Variations in surface residual compressive stress and magnetic induction intensity were analyzed. When residual compressive stress changed markedly, the change in magnetic induction intensity reflected the change in residual compressive stress. With the increase in residual compressive stress, the surface magnetic induction intensity and residual compressive stress of the specimen exhibited an approximate linear relationship, manifesting an increasing trend. Therefore, residual compressive stress was analyzed by detecting the changes in the surface magnetic induction intensity of specimens. Micromagnetic nondestructive detection allows the effective detection of the surface residual compressive stress of 304 stainless steel.