Reason analysis and improvement measures for cracking and spalling of nitriding iron pot for cold rolled strip steel
In the process of making iron pots using XLQ01 cold-rolled strip steel with a thickness of 1 mm produced by a company,cracking problems occurred after nitriding treatment,and the nitriding layer of iron pots was easy to peel off after collision.In this study,scanning electron microscope,direct-reading spectrometer,metallurgical microscope and other detection methods were used to analyze the microstructure,chemical composition,metallographic structure,and surface roughness,chemical composition,metallographic structure,and grain size of nitriding iron pot samples.The results showed that the main reasons for the cracking and spalling of nitriding iron pots are as follows:on the one hand,the presence of coarse original structure and needle like nitrides with transgranular distribution in the nitriding cracked samples disrupts the continuity of the matrix,and increases the brittleness of the surface layer and sensitivity to notches,leading to cracking under external forces;on the other hand,the surface roughness of raw materials is large,the nitriding temperature is high,and the nitriding layer is loose,which leads to cracking and spalling of the nitriding layer under compressive stress.In this study,corresponding improvement measures are proposed to address the causes of cracking and peeling in nitriding iron pots,which effectively avoid the cracking and spalling.
cold rolled strip steelnitriding iron potcrackingspalling
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