Series f-grade steel for ships and ocean engineering and its flexible production method

Abstract

The invention relates to F grade steel used for a series of ships and ocean engineering. The steel is prepared from the chemical components of, in percentage by mass, 0.05-0.09% of C, 0.15-0.50% of Si, 0.80-1.30% of Mn, less than or equal to 0.0070% of P, less than or equal to 0.0030% of S, 0.10-0.30% of Ni, 0.008-0.020% of Ti, 0.0030-0.0060% of N, 0.020-0.050% of Nb, 0.020-0.050% of Al and the balance Fe and inevitable impurity elements. According to a production technology process, by conducting hot metal pretreatment, converter steel-making, LF refining, RH vacuum degassing, Ca treatment, continuous casting, casting blank dehydrogenation treatment, heating, rolling, cooling (strip temperature straightening) in combination with reasonable component designing, control of tissues and crystal grain dimensions of different steel plates is conducted, multi-strength grade flexibility production of four steel grades of 235 MPa, 315 MPa, 355 MPa and 400 MPa is completed, the low-temperatureimpact toughness is excellent, the ductility is excellent, and is higher than or equal to 25%, a high cooling speed and a thin plate shape are guaranteed, the production technology is stable, and batch production is easy.

Description

technical field [0001] The invention belongs to the field of iron and steel metallurgy, and in particular relates to a series of F-grade steel for ships and marine engineering and a flexible production method thereof. Background technique [0002] At present, the main steel grades for marine engineering are still D grade and E grade steel with strengths of 235MPa, 315MPa and 355MPa. With the development of new sea routes in the deep sea and the Arctic Ocean, the main steel grades in the ocean tend to develop towards higher strength grades such as 400MPa grade steel, F grade with higher low temperature toughness requirements, and even lower temperature toughness steel. Due to the application in severe marine working environments such as waves, sea tides, storms, and cold drift ice, it is required that the steel used for ship and ocean engineering structures must not only have properties such as strength, toughness, and low temperature resistance, but also have anti-lamination...

AI Technical Summary

Problems solved by technology

In these existing technologies, only a single F-grade steel grade has been studied

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