A kind of low-cost boron-containing steel and its manufacturing method

Abstract

The invention discloses a low-cost boron-containing steel and a manufacturing method thereof. The steel comprises the following chemical components by weight: 0.05%-0.08% of C, 0.10-0.25% of Si, 1.60%-1.80% of Mn, 0.03%-0.045% of Als, 0.030%-0.045% of Ti, 0.003%-0.009% of B, less than or equal to 0.025% of P, less than or equal to 0.015% of S, less than or equal to 0.0015% of O, less than or equal to 0.0025% of N, and the balance Fe and unavoidable impurities. At the later stage of LF (ladle furnace) refining, by adding aluminum to perform deoxidation and adding ferrotitanium to undergo nitrogen fixation, the content of O and N in the steel can be controlled, and finally by adding ferroboron, the yield of boron and the distribution uniformity of boron in the steel can be guaranteed. Specifically, the heating temperature is at 1120-1180DEG C, and the heating time is 90-120min; the initial rolling temperature of hot rolling is 1090-1150DEG C, and the final rolling temperature is 790-850DEG C; the initial cooling temperature is 750-810DEG C, and the terminal cooling temperature ranges from (500-540)-30DEG C to (500-540)+30DEG C. In the invention, by control of boron in the steel to avoid combination with oxygen and nitrogen, the content of boron in solid solution in the steel can be ensured, and the reinforcement effect of boron can be improved. Through changing the adding amount of boron and adjusting the temperatures of heating, hot rolling and cooling, the low-cost boron-containing steel with strength levels of 460MPa, 500MPa and 550MPa can be obtained.

Description

technical field [0001] The invention belongs to the technical field of metallurgy, and in particular relates to a low-cost boron-containing steel and a manufacturing method thereof. Background technique [0002] As an alloying element added to steel, B has been found to have beneficial effects for a long time. For example, adding 0.001% to 0.002% of B to steel can significantly improve the hardenability of steel, increase the hardenable size of steel, and improve The uniformity of structure and properties in the steel section after quenching; B is also used to improve the high-temperature mechanical properties of some steels, such as high-temperature creep properties and enduring strength. As early as the beginning of the 20th century, attempts to add trace amounts of B to steel began abroad. Domestically, the development of B-containing steel is relatively backward. In the 1980s, China began to study the influence of B on the properties of steel. For example, He Xinlai and...

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Problems solved by technology

In addition, in the prior art, there is no clear limit to the content of O and N in the steel, or the limit range is relatively wide, which will cause the combination of O, N and B elements in the steel, affecting the contribution of B to the improvement of strength

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