Method for testing reinforcing steel bar center martensite structure

Abstract

The invention relates to a method for testing martensitic structure in the center of a steel reinforcement, which comprises the following steps: firstly, cutting two segments of longitudinal test samples of steel reinforcements, connecting two steel reinforcement samples with the same diameter in a tangential way to form a mosaic block, secondly, removing the mosaic block from the central portionnear the upper portion of the cross section, using the mosaic block whose lower portion is bigger than a semi circle to be a test sample, thirdly, burnishing the cut surface of the test sample till no gap exists between the two segments of the steel reinforcement samples, namely the central portion has no gap, fourthly, corroding the cut surface which is polished by nitric acid alcohol solution, and finally, observing the central portion of the steel reinforcements by a metalloscope, and the central white bright vitta band is the martensitic structure band. The method can rapidly test and evaluate martensitic structure in the center of a steel reinforcement, can effectively solve the quality inspection problem of steel reinforcements, and can satisfy the production requirements.

Description

technical field [0001] The invention relates to a method for inspecting the quality of steel, in particular to an inspection method for the central martensite structure of steel bars. Background technique [0002] High-carbon hypereutectoid steel hot-rolled wire rod (also known as steel bar) is prone to produce martensite structure due to segregation in the center during the production process. Therefore, it is necessary to test the central martensitic structure of steel bars. [0003] There are two key points in the inspection of the central martensite structure: (1) The preparation of the longitudinal sample. The longitudinal sample must be used to test the central martensite of the wire rod, but it is difficult to determine the center position of the longitudinal sample. If the sampling position is not Center or far away from the center, the central martensite structure cannot be observed. The current general sample preparation method is to measure the size of a steel b...

AI Technical Summary

Problems solved by technology

[0003] There are two key points in the inspection of the central martensite structure: (1) The preparation of the longitudinal sample. The longitudinal sample must be used to test the central martensite of the wire rod, but it is difficult to determine the center position of the longitudinal sample. If the sampling position is not Center or far away from the center, the central martensitic structure cannot be observed

The current general sample preparation method is to measure the size of a steel bar with a ruler, then cut a part of the longitudinal sample to the vicinity of the center position, and then grind and corrode and observe, and go back and forth many times to determine the position of the central martensite structure. The efficiency of sample preparation is very low, resulting in a long inspection time and affecting production

(2) Grading of the central martensitic structure. If the severity of the central martensitic structure is not graded and evaluated, the severity cannot be judged, nor can the quality of the wire rod be judged. At present, there is no central martensitic structure. rating method

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