百米高速重轨属于高碳钢，在加热过程中表面极易出现脱碳，脱碳层深度检验是百米高速重轨最重要的检验项目之一。TB/T 2344-2012标准规定脱碳层深度不大于0.50 mm，该标准规定的脱碳层检验方法与GB/T 224-2019标准中规定的检验方法不同。TB/T 2344-2012标准中脱碳层深度检验方法是测定试样表面到连续封闭铁素体网的深度；GB/T 224-2019标准中脱碳层深度检验方法则是测定试样表面至脱碳最深处深度的平均值。

100 m high speed heavy rail belongs to high carbon steel, and decarburization is easy to occur on the surface during heating. The depth inspection of decarburization layer is one of the most important inspection items of 100 m high speed heavy rail. TB/T 2344-2012 standard stipulates that the depth of decarburization layer shall not be greater than 0.50 mm. The inspection method of decarburization layer specified in this standard is different from that specified in GB/T 224-2019 standard. The depth test method of decarburization layer in TB/T 2344-2012 standard is to measure the depth from the sample surface to the continuous closed ferrite mesh. In GB/T 224-2019, the inspection method of decarburization layer depth is to determine the average value from the sample surface to the deepest depth of decarburization.