Steel plate spring composite shot blasting strengthening method

The invention discloses a steel plate spring composite shot blasting strengthening method. The method comprises the following steps that one-time shot blasting is carried out, and shot blasting process parameters are as follows: alloy steel shots of phi 1.0 mm-1. 2mm are selected as a shot blasting medium, the shot speed is 75m/s-85m/s, the shot blasting strength is greater than 0.50 mmA, and thecoverage rate is greater than or equal to 100%; and second-time particle shot blasting is carried out, and shot blasting process parameters are as follows: a shot blasting medium is selected from ultrafine alloy steel shots with the diameter phi of 50-100 microns, the shot speed is 120 m/s, the shot blasting strength is 0.15 mmA, and the coverage rate is greater than or equal to 100%. According tothe method, the advantage that the residual compressive stress brought by shot blasting strengthening of large-particle-size shot blasting is distributed along the depth of the sub-surface layer of asteel plate spring is rese