Austenitic steel having excellent surface characteristics, and method of manufacturing the same

Abstract

The present disclosure relates to an austenitic steel having excellent surface characteristic, and a method of manufacturing the same. Provided are an austenitic steel having excellent surface characteristic, and a method for producing the same, the austenitic steel according to an aspect of the present disclosure comprising, by weight, carbon (C): 0.6% to 1.3%, manganese (Mn): 14% to 22%, copper (Cu): 5% or less (excluding 0%), chromium (Cr): 5% or less (excluding 0%), silicon (Si): 1.0% or less (excluding 0%), aluminum (Al): 0.5% or less (excluding 0%), phosphorus (P): 0.1% or less (including 0%), sulfur (S): 0.02% or less (including 0%), a remainder of iron (Fe), and inevitable impurities, wherein a microstructure of the austenitic steel comprises, by area, 5% or less of carbide and a remaining austenite structure, and a surface defect size of the austenitic steel is 0.3 mm or less.

Description

TECHNICAL FIELD[0001]The present disclosure relates to an austenitic steel having excellent surface characteristics, and a method of manufacturing the same.BACKGROUND ART[0002]The present disclosure relates to an austenitic steel material, excellent in terms of wear resistance, used in the mining, transportation and storage fields in oil and gas industries such as for industrial machinery, structural materials, a steel material for slurry pipes, a steel material in sour service, and a method for producing the same, and more particularly to an austenite steel material, having excellent surface characteristic, and excellent in wear resistance, toughness, and corrosion resistance, and the like, as well as ductility, and a method for producing the same.[0003]The austenitic steel may be used for various purposes due to characteristics thereof such as process hardenability, non-magnetic properties, and the like. Particularly, as carbon steel having ferrite and martensite as a main structu...

AI Technical Summary

Benefits of technology

The present patent is about a type of steel that has excellent surface quality, making it suitable for use in fields where wear resistance is needed, such as mining, transportation, storage, and industrial machinery. This steel can also be used in fields that require a high level of surface quality. Additionally, using this steel can reduce the need for surface repair and improve productivity and efficiency.

Problems solved by technology

In particular, due to the growth of the mining industry as well as the oil and gas industries, wear of a steel material used in mining, transportation, refining, and storage processes, is becoming a significant problem.

Particularly, as the development of oil sands as a source of fossil fuel to replace petroleum has been regularized, wear of a steel material, caused by a slurry including oil, gravel, sand, and the like, is a main cause of an increase in production costs.

However, the high content of carbon the Hadfield steel may cause network-type carbides to form at high temperatures along the austenite grain boundaries, thereby drastically lowering the properties of the steel material, particularly ductility.

However, the Hadfield steel has excellent wear resistance in a general mechanical wear environment, but it is difficult to exhibit excellent wear resistance in an environment where corrosion wear is accompanied, so that it is difficult to apply to a harsh environment in which complex wear occurs.

However, deterioration of toughness due to precipitation of carbides may be a problem in austenitic wear resistant steel having a very high content of carbon.

Further, segregation due to alloying elements such as manganese, carbon, and the like, in solidification may be inevitably generated in the case of an ingot or casting piece of the high manganese steel.

As a result, non-uniformity of a microstructure may be promoted, and properties thereof may be deteriorated.

Another problem may be non-uniform oxidation occurring on the surface.

Such non-uniform oxidation may especially occur along the grain boundaries, causing cracks in the slab reheating process, and propagating the cracks during the rolling process in which stress occurs, to deteriorate the surface characteristics of the final product.

Cracks on the surface may cause premature failure in product bending or tensioning process, and may reduce wear resistance thereof.

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