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: A polyimide resin composition includes a polyimide resin (A) including a repeating structural units of formulas (1) and (2). The content ratio of the repeating structural unit of the formula (1) with respect to the total of the repeating structural units of the formulas (1) and (2) is 20 to 70 mol %. The polyimide resin composition further includes a fatty acid metal salt (B) including a fatty acid having 12 to 36 carbon atoms and optionally having a hydroxy group and at least one of an alkali metal, an alkaline earth metal, and a transition metal: wherein R1 represents a divalent group having 6 to 22 carbon atoms containing at least one alicyclic hydrocarbon structure; R2 represents a divalent chain aliphatic group having 5 to 16 carbon atoms; and X1 and X2 each independently represent a tetravalent group having 6 to 22 carbon atoms containing at least one aromatic ring.