Wire rod for prestressed concrete steel stick and manufacturing process

Abstract

The invention relates to a novel steel wire rod and a manufacturing technique thereof. A prestressed steel bar used as the distributed steel of tubular piles is a new product developed in recent years, and the raw material thereof, namely, the steel wire rod, has no special steel and production technique; the controls for the components and performances, etc. of the steel wire rod are different, which results in larger fluctuation thus bringing the producers and the users more difficulties; therefore, the novel steel wire rod and the manufacturing technique thereof are invented. The components of the novel steel by weight percentage are: 0.28-0.34 percent of C, 0.70-1.10 percent of Si, 1.10-1.50 percent of Mn, less than or equal to 0.025 percent of S, less than or equal to 0.025 percent of P, less than or equal to 0.25 percent of Ni, less than or equal to 0.25 percent of Cr and less than or equal to 0.20 percent of Cu; the adopted technique is converter - ladle furnace (LF) refining - continuous casting - highline mill; in the converter process, high lance height is adjusted, returned slag by the converter is added in the front period, and the alkalinity is controlled in the middle and late period; stirring is done under soft blowing before the end of the process, and then deoxidation by adopting SiAlBa is carried out; in the ladle furnace (LF) refining process, reductive white slag is adopted, the CaSi wires are fed and before finishing the refining, and soft argon blowing is done; in the continuous casting process, the degree of superheat and the casting speed of the molten steel are controlled and casting is preformed under whole course protection; in the rolling process, the delayed cooling technique is adopted. The novel steel wire rod, when in use, the control range of the components is narrow, therefore, the fluctuation of adjacent batches is small; the performance of the novel steel wire rod is stable, and the aberration thereof is small.

Description

technical field [0001] The invention relates to a wire rod of a new steel type and its manufacturing process, in particular to a wire rod steel type for prestressed concrete steel bars and the processes of smelting, LF refining, continuous casting and rolling. technical background [0002] Prestressed concrete steel rods are used as reinforcement for construction pipe piles. Since prestressed concrete steel rods are new products developed in recent years, the raw materials used are wire rods. According to their performance requirements, steel types with similar performances are selected. For a long time, there have been no special standards for wire rods for prestressed concrete steel rods at home and abroad, and domestic and foreign manufacturers have no special steel grades and production process routes for this product. The physical quality fluctuates greatly, which brings many difficulties to manufacturers and downstream users. [0003] At present, the production of wir...

AI Technical Summary

Problems solved by technology

The production cost of the traditional process is low, but due to the limitation of refining methods and time, the refining effect of molten steel is not good, the inclusions in the steel cannot be fully removed, and it is difficult to achieve deep desulfurization of molten steel, which in turn affects the drawing performance of the wire rod

At the same time, the control accuracy of molten steel composition is low, which also causes fluctuations in wire rod performance

[0004] In order to overcome the disadvantages of unfixed, large fluctuation and unstable manufacturing process of selected steel grades with similar properties, the present invention invents a wire rod product for prestressed concrete steel rods and the manufacturing process of the product, inventing a main component For (by weight) C=0.28-0.34%, Si=0.70-1.10%, Mn=1.10-1.50%, S≤0.025%, P≤0.025%, Ni≤0.25%, Cr≤0.25%, Cu≤ 0.20%, wire rod products, and adopt the process route of "converter → LF ladle refining → continuous casting → high wire rolling" to produce wire rods for high-strength prestressed concrete steel rods

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