Abrasion resistant steel having excellent hardness and impact toughness and manufacturing method therefor

Abstract

One embodiment of the present disclosure provides an abrasion resistant steel having excellent hardness and impact toughness, and a manufacturing method therefor, the steel comprising, by wt %, 0.33-0.42% of C, 0.1-0.7% of Si, 0.6-1.6% of Mn, 0.05% or less of P, 0.02% or less of S, 0.07% or less of Al, 0.55-5.0% of Ni, 0.01-1.5% of Cu, 0.01-0.8% of Cr, 0.01-0.8% of Mo, 50 ppm or less of B, and 0.02% or less of Co, further comprising one or more selected from the group consisting of 0.02% or less of Ti, 0.05% or less of Nb, 0.05% or less of V and 2-100 ppm of Ca, and comprising the balance of Fe and other inevitable impurities, wherein C and Ni satisfy the following relation 1, and the microstructure comprises 95 area % or more of martensite and 5% or less of bainite (including 0%). [Relation 1] [C]×[Ni]≥0.231

Description

TECHNICAL FIELD[0001]The present disclosure relates to a high hardness abrasion resistant steel and a manufacturing method therefor, and more particularly, to a high hardness abrasion resistant steel which may be used for construction machinery, and the like, and a manufacturing method therefor.BACKGROUND ART[0002]As for construction machinery and industrial machinery used in many industrial fields such as construction, civil engineering, mining, and cement industries, since abrasion may occur severely due to friction in operation, it may be necessary to apply a material exhibiting abrasion resistance properties.[0003]Generally, as abrasion resistance and hardness of a thick steel sheet may be correlated with each other, it may be necessary to increase hardness in the thick steel sheet concerned, to be worn down. To secure stable abrasion resistance, it may be necessary to have uniform hardness from the surface of the thick steel sheet to the inside (around t / 2, t=thickness) of the ...

AI Technical Summary

Benefits of technology

The present disclosure provides a way to make a thick abrasion-resistant steel with high hardness and low-temperature toughness. This is achieved through a controlled content of carbon (C), silicon (Si), manganese (Mn), and phosphorus (P) in the steel composition. Carbon and silicon are and effective in improving strength and hardness, with manganese being effective in preventing the formation of ferritte and improving hardenability. However, manganese and phosphorus can negatively impact toughness, so it is important to control their content within certain ranges. By controlling these content ranges, the present disclosure provides a way to make a high-quality thick steel with excellent abrasion resistance and low-temperature toughness.

Problems solved by technology

As for construction machinery and industrial machinery used in many industrial fields such as construction, civil engineering, mining, and cement industries, since abrasion may occur severely due to friction in operation, it may be necessary to apply a material exhibiting abrasion resistance properties.

However, to manufacture an extremely thick steel sheet, it may be necessary to add a greater amount of hardenability elements to secure hardenability in the center of the steel sheet, and as C and hardenability alloys are added in large amounts, manufacturing costs may increase, and weldability and low-temperature toughness may degrade, which may be problematic.