Drahtstahl for high strength fastening piece and production method thereof

Abstract

The invention relates to a drahtstahl for a fastening piece and a production method thereof, and the drahtstahl comprises the following components by weight percent: 0.39-0.48 % of C, 0.15-0.35% of Si, 0.30-0.90% of Mn, 0.60-1.20% of Cr, 0.010-0.07% of Als, less than or equal to 0.035% of P, less than or equal to 0.035% of S and the balance Fe and unavoidable impurity; and the production method comprises the following steps: smelting with a clean steel process and casting into a blank, and adding Si-Ca line in the refining; heating the continuous casting to 980-1,080 DEG C; rough rolling: controlling the deflection to be 70-80%; intermediate rolling: controlling the deflection to be 80-90%; pre-precision rolling: controlling the deflection to be 65-75%; water-cooling until the temperature is cooled to be 1,000-1,020 DEG C; precision rolling: controlling the deflection to be 60-90%; water-cooling for the second time until the temperature is cooled to be 800-900 DEG C; spinning; cooling to phase change initial temperature, namely the range from Ar3 to 50 DEG C higher than Ar3 by adopting an aerial fog mixed method; and continually cooling until the temperature is cooled to be 400-500 DEG C and naturally cooling to environment temperature. The invention can be drawn directly, has good cold deformation and is not easy to crack.

Description

technical field

[0001] The invention relates to wire steel for fasteners and a production method thereof, in particular to wire steel for making grade 8.8-10.9 fasteners and a production method thereof. Background technique

[0002] In recent years, with the rapid development of my country's machinery manufacturing and automobile industries, the demand for high-strength fasteners has grown rapidly. According to reports, in 2008, the output of medium and high-grade alloy cold heading steel for automotive fasteners alone exceeded 1.2 million tons. The market demand is strong. This work is used to produce 8.8-10.9 grade fastener products, and the manufactured fasteners can bear the tensile strength of 1000MPa grade.

[0003] With the development of converter smelting technology, it has become a trend to produce alloy steel wire rods by converter continuous casting process, which has significantly improved the quality of steel. In order to satisfy high-strength fasteners with...

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