Method for measuring dissolving temperature of Nb (C,N) in low-carbon micro-alloyed steel by internal friction method

The invention provides a method for measuring dissolving temperature of Nb (C,N) in low-carbon micro-alloyed steel. According to the method, the content of niobium in low-carbon micro-alloyed steel components exceeds 0.01 percent, and the C content is smaller than 0.2 percent. The method comprises the following steps of: performing solution treatment on a sample which is fully separated out through Nb (C,N); tempering the sample subjected to the solution treatment at 350 DEG C higher than the SKK peak occurrence temperature for 60 to 70 minutes; measuring the sample through the internal friction method, so as to obtain the strength and temperature changing curve of the material SKK internal friction peak; and determining the dissolving temperature of Nb (C,N). The method is high in testing precision and has high applicability on the Nb-containing low-carbon micro-alloyed steel with different components.