Method for quickly inspecting mechanical property of twisted steel

Abstract

The invention belongs to the technical field of smelting, and particularly relates to a method for quickly inspecting mechanical properties of twisted steel, which comprises the following steps of: cooling hot-rolled twisted steel of which the lower cooling bed temperature is less than or equal to 430 DEG C to room temperature by adopting any cooling mode of air cooling or normal-temperature watercooling, and detecting the yield strength, the tensile strength and the elongation of the hot-rolled twisted steel. By adopting the method disclosed by the invention, the natural cooling time is saved, and the yield strength Rel, tensile strength Rm and elongation A mechanical property indexes of the hot-rolled twisted steel can be quickly and accurately measured.

Description

technical field [0001] The invention belongs to the technical field of smelting, and in particular relates to a quick inspection method for the mechanical properties of threaded steel bars. Background technique [0002] In the production and inspection process of steel products, in order to truly detect the mechanical properties of steel at room temperature and reduce damage to the testing equipment, the mechanical performance test of threaded steel bars needs to be tested after the sample is cooled to room temperature. [0003] At present, under the current technological conditions, the threaded steel bars (HRB400, HRB500) produced by steel mills, after the steel is cooled in the bed, the small size It takes about 120 minutes to cool down to room temperature under natural cooling conditions, medium specification It takes about 180min to cool down to room temperature, large size ( above) takes longer. Due to the long natural cooling time of threaded steel bars (HRB40...

AI Technical Summary

Problems solved by technology

Due to the long natural cooling time of threaded steel bars (HRB400, HRB500), the steel bars cannot be detected and judged in time after they are offline, which affects the outgoing products and logistics transportation, and greatly increases the backlog time of steel in the warehouse area.

In addition, due to the delay in the inspection of mechanical properties, it also brings difficulties to process optimization and adjustment, and it is impossible to formulate timely and effective measures to reduce waste products caused by improper process adjustment.

[0004] In order to improve the speed of inspection and chemical inspection, if the high-temperature sample is directly tested, the deviation of the test result will be large. During the plastic deformation stage of the tensile test, due to the dynamic recovery of the high temperature of the sample, the tensile strength is reduced. At the same time, the tensile test process of the metal is actually the deformation process of the metal. The plastic deformation of the sample is actually the dislocations in the crystal of the sample begin to slip. The dislocation slip is hindered by the second-phase particles and grain boundaries. The greater the degree of hindrance, the greater the force required for dislocation slip and the more difficult the plastic deformation. However, the high-temperature sample not only weakens the second-phase particles and grain boundaries. The hindering effect of the boundary also makes the dislocation climb and weakens the hindering effect between dislocations, which is manifested as a decrease in the yield strength in the macroscopic view.

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