High-strength and high-toughness hot-rolled yoke steel with yield strength larger than or equal to 750MPa and production method

Abstract

The invention relates to high-strength and high-toughness hot-rolled yoke steel with the yield strength larger than or equal to 750MPa. The high-strength and high-toughness hot-rolled yoke steel comprises the following components in percentage by weight: 0.015-0.030 percent of C, at most 0.15 percent of Si, 1.80-2.10 percent of Mn, at most 0.015 percent of P, at most 0.005 percent of S, 0.035-0.075 percent of Ti, 0.02-0.07 percent of Nb, 0.02-0.10 percent of Als and at most 0.005 percent of N. The production method of the high-strength and high-toughness hot-rolled yoke steel comprises the following steps: after molten iron desulphurization, converter combined blowing and vacuum treatment, pouring; heating plate billets; rough rolling; finish rolling; laminar flow cooling; coiling. The yield strength is larger than or equal to 750MPa, the tensile strength is larger than or equal to 800MPa, the elongation A is larger than or equal to 11percent, -40 DEG C impact energy KV2 is larger than or equal to 60J, the magnetic inductivity B50 is larger than or equal to 1.50, and all the parameters can meet the demand of high-strength and high-magnetic-inductivity steel for a super-huge type hydro-generator rotor yoke with high capacity per unit.

Description

technical field [0001] The invention relates to a hydraulic generator rotor yoke steel and a production method thereof, in particular to a high-strength and high-toughness hot-rolled yoke steel with a yield strength ≥ 750 MPa and a production method thereof. Background technique [0002] With the implementation of the "Western Development" strategy and the "West-to-East Electricity Transmission" strategy determined by our country, and in accordance with the national guideline of "vigorously developing hydropower", a large number of large-scale hydropower projects will start construction in the next few decades. With the development of the hydropower industry, the performance requirements for the yoke steel plate used in the key part of the rotor yoke of the hydro-generator have also increased from simple high strength to high toughness, especially in severe cold regions. The service environment of steel is harsh, and once the material breaks during the operation of the rotor...

AI Technical Summary

Problems solved by technology

However, this level of toughness steel can no longer adapt to and meet the current generator requirements of large-scale hydropower projects, so it is urgent to research and develop high-strength and high-toughness yoke steel

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