The main market for high-precision cold drawn tubes is the construction weighing industry. However, this industry also has relatively high tensile strength requirements for cold drawn steel tubes, so how can we strengthen the tensile strength of cold drawn tubes?
1. The hydrostatic test can be replaced by eddy current testing. The test pressure or eddy current flaw detection sample size shall comply with relevant regulations. The mechanical properties of steel are important indicators for ensuring the performance of high-precision cold-drawn tubes, which depends on the chemical composition of the steel and the heat treatment system. In the steel pipe standard, according to different use requirements, the tensile properties, hardness and toughness indicators are specified, as well as the high and low temperature properties required by the user.
2. Tensile strength (σb) of high-precision cold-drawn tube: The stress (Fb) that the sample bears when it is broken during the tensile process is derived from the stress obtained by the original cross-sectional area (So) of the sample ( σ), called tensile strength (σb), the unit is N / mm2 (MPa). It represents the ability of metal materials to resist destruction under the action of tension. In the formula: Fb-the force that the sample bears when it is broken, N (Newton); So-the original cross-sectional area of the sample, mm2. If the force drops, the upper and lower cold-drawn pipes should be distinguished. The unit of cold drawn tube is N / mm2 (MPa). Upper cold-drawn tube (σsu): the stress before the sample yields and the force first decreases; lower cold-drawn tube (σsl): the stress in the yield stage when the initial transient effect is not counted. In the formula: Fs--the yield force (constant) during the tensile process of the sample, N (Newton) So--the original cross-sectional area of the sample, mm2. Elongation after breaking: (σ) In the tensile test, the percentage of the length that the gauge length increases after the sample is broken and the length of the original gauge length is called elongation.