The standard material is T 12 or T 13, which is the material with the highest carbon content in carbon tool steel. The document is in a fragile state, and it is not allowed to be used as a hammer or crowbar when it is used. It is normal to fall at the normal operating height and cause fractures, so it is not suitable for daily use.

The hardness of general steel files is usually above 60HRC. In terms of chemical composition, the carbon content is very high, which generally needs to reach 1.0~ 1.3%, and it must be heat treated, otherwise even if the carbon content is very high.

Still can't reach that high hardness. In general, the heat treatment of quenching and low temperature tempering is usually adopted, so that the martensite structure with high hardness can be obtained and the high hardness can be maintained.

Extended data:

File type:

1, divided into: general locksmith file for general filing; Wood file, used for filing soft materials such as wood and leather; Plastic file (assorted file) is used to file small and thin metal parts, and a set of files with various cross-sectional shapes; Knitting file of woodworking saw; Special files, such as flat and arched special-shaped files (special files), are straight and curved.

2. Files are divided into flat files (flat files), square files, semi-circular files, round files, triangular files, diamond files and knife files (see figure). Flat files are used to file curved surfaces, cylindrical surfaces and convex surfaces.

Square file is used to file square holes, long square holes and narrow planes; Triangular files are used to file internal corners, triangular holes and planes; Semi-circular file is used to file concave curved surfaces and planes; Circular file is used to file round holes, concave cambered surfaces with smaller radius and elliptical surfaces.

3. According to file types, files are divided into single files and double files. The cutter teeth of single file are inclined at a certain angle with the axis, which is suitable for processing soft non-ferrous metals; The main file and the auxiliary file of the double-edged file are alternately arranged, and are used for processing steel and nonferrous metals. It can divide a wide file into many small pieces to make the file lighter.

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