Abstract: Provided is a method of manufacturing a spring for inspecting the stress distribution of the spring under load. The method for manufacturing a spring (1) includes the steps of applying a load to the spring (1), measuring the stress of the spring (1) under the load, and releasing the load applied to the spring (1), the measuring the stress of the spring (1) being made by measuring the stress on the surface of the active part of the spring (1) using X-ray diffraction with the cos ? method, and the method further including the step of determining whether the magnitude of the stress of the spring (1) meets a criterion.

Abstract: Provided is a method of manufacturing a spring for inspecting the stress distribution of the spring under load. The method for manufacturing a spring (1) includes the steps of applying a load to the spring (1), measuring the stress of the spring (1) under the load, and releasing the load applied to the spring (1), the measuring the stress of the spring (1) being made by measuring the stress on the surface of the active part of the spring (1) using X-ray diffraction with the cosa method, and the method further including the step of determining whether the magnitude of the stress of the spring (1) meets a criterion.

Abstract: The present invention provides a composite material suitable for thermal plastic processing, and having a coating layer that includes a heat-resistant resin having a melting point or pyrolysis temperature of 150° C. or more on the surface of at least one side, and preferably both sides, of a magnesium (alloy) plate. The heat-resistant resin is preferably a thermosetting resin based on polyimide. By using the composite material of the invention, processing with a high degree of processing, such as deep drawing and formation of complex ribs and bosses, can be achieved easily by thermal plastic processing. The present invention also provide a magnesium (alloy) plastic-processing product obtained by plastic processing by using the composite material.