A kind of annealing-free wire rod for 05-grade high-strength nuts and its production method

Abstract

The invention provides an annealing-free wire rod for a 05-grade high-strength nut and a production method of the annealing-free wire rod. The annealing-free wire rod comprises the following chemical components in percentage by weight: 0.19-0.36% of carbon, 0.55-0.85% of manganese, less than or equal to 0.08% of silicon, less than or equal to 0.025% of sulfur, less than or equal to 0.025% of phosphorus and 0.0015-0.004% of boron. The annealing-free wire rod provided by the invention has the tensile strength of 530Mpa or lower, the elongation percentage of high than or equal to 25% and the surface shrinkage percentage of 50% or higher and has qualified 1 / 3 cold heading performance and excellent integral performance. Due to the adoption of the method, the annealing step is omitted, the production cost of the nut is reduced, and significant consumption reducing, energy saving and environment protecting effects are achieved.

Description

technical field [0001] The invention belongs to the technical field of steel production and processing technology, and more specifically relates to a non-annealing wire rod for 05-grade high-strength nuts, and also relates to a production method of the non-annealing wire rod. Background technique [0002] The medium-carbon cold heading steel produced according to the metallurgical production process in the prior art, in the process of making 05 high-strength thin-walled nuts, in order to meet the requirements of large deformation and thin-walled cold heading processing performance, in the process of cold drawing Before cold heading and forming, time-consuming and energy-consuming spheroidizing annealing treatment is required to achieve low deformation resistance and excellent plasticity. This kind of annealing treatment often has a long cycle, consumes a lot of energy and resources, and pollutes the environment. . Chinese patent: Patent No. 99115353.7, spheroidizing anneali...

AI Technical Summary

Problems solved by technology

Although the medium carbon cold heading steel wire rod can be directly softened online, the annealing medium carbon cold heading steel wire rod can be made into 8.8 high-strength bolts, and the annealing process before cold heading is omitted, but because only the pearlite carbide is crushed It is only partly spheroidized, so it can only be used for internal and external hexagonal bolts of grade 8.8 without annealing, and it cannot be used for nut fasteners with complex shapes.