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A steel rebar and a production method thereof

Inactive Publication Date: 2017-02-02
INST OF RES OF IRON & STEEL JIANGSU PROVINCE
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

The patent aims to provide a solution for improving the corrosion resistance of steel rebar in ocean environments, which is currently a technical problem for reinforced concrete structures. The invention offers a steel rebar with excellent corrosion resistance and comprehensive mechanical properties and describes a production method for it.

Problems solved by technology

Meanwhile, the durability problem of steel rebar used as a main structural material becomes increasingly prominent.
The ocean environment is a relatively harsh corrosion environment in the nature, with its special conditions of high temperature, high humidity, and high salinity easily causing corrosion of steel.
Severe corrosion usually occurs in the reinforced concrete structures along the coast of China after 10-15 years on service, which results in damage to the structures, rendering the structures unable to meet their designed service life of 50 years.
Among coated corrosion resistant steel rebar products, epoxy coated steel rebar is researched earliest and used most widely, however, epoxy coated steel rebar has essential disadvantages reflected as: the coating has high brittleness, and is easily damaged and shed off during transporting and processing; defects in the coating might cause concentrated corrosion which leads to severe local corrosion; the bond stress between epoxy coated steel rebar and concrete is reduced as compared to ordinary steel rebar, etc.
But its cost is expensive, at about 6-10 times that of ordinary carbon steel rebar, therefore, it cannot be used for large scale application in engineering, and is normally used only at key positions of structures or in relatively harsh environments.
Furthermore, macro cell corrosion easily occurs when stainless steel rebar is overlapped with ordinary steel rebar, which also adversely affect the service life of structures.
Corrosion resistance performances of these steels are enhanced to a great extent compared to ordinary carbon steel, but they still cannot meet the prolonged service life required in reinforced concrete structures.
Therefore, all of these types of steels cannot be used in oceanic reinforced concrete structures.

Method used

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  • A steel rebar and a production method thereof

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embodiment 1

[0042]The present embodiment provides a steel rebar, comprising the following elements: C, Si, Mn, P, S, Cr, Mo, Sn, Rare Earth element, Fe and unavoidable impurities, wherein, the weight percentages of the ingredients are as shown in Table 1, the mechanical properties are as shown in Table 2, and the corrosion resistance performance is as shown in Table 3.

[0043]The present embodiment also provides a production method of steel rebar comprising the following steps:

S1: performing preliminary desulfurization of molten iron by using a KR method to control the sulfur content at no more than 0.01%. Because sulfur element as an impurity element would reduce mechanical properties and corrosion resistance performance of steel and normally cannot be removed in a convertor, therefore, in order to reduce the sulfur content in steel, preliminary desulfurization treatment needs to be performed in molten iron. Before performing desulfurization, the blast furnace slag needs to be removed in order t...

embodiment 2

[0044]The present embodiment provides a steel rebar, comprising the following elements: C, Si, Mn, P, S, Cr, Mo, Sn, Rare Earth element, Fe and unavoidable impurities, wherein, the weight percentages of the ingredients are as shown in Table 1, the mechanical properties are as shown in Table 2, and the corrosion resistance performance is as shown in Table 3.

[0045]The present embodiment also provides a production method of steel rebar comprising the following steps:

S1: performing preliminary desulfurization of molten iron by using a KR method to control the sulfur content at no more than 0.01%. Because sulfur element as an impurity element would reduce mechanical properties and corrosion resistance performance of steel and normally cannot be removed in a convertor, therefore, in order to reduce the sulfur content in steel, preliminary desulfurization treatment needs to be performed in molten iron. Before performing desulfurization, the blast furnace slag needs to be removed in order t...

embodiment 3

[0046]The present embodiment provides a steel rebar, comprising the following elements: C, Si, Mn, P, S, Cr, Mo, Sn, Rare Earth element, Fe and unavoidable impurities, wherein, the weight percentages of the ingredients are as shown in Table 1, the mechanical properties are as shown in Table 2, and the corrosion resistance performance is as shown in Table 3.

[0047]The present embodiment also provides a production method of steel rebar comprising the following steps:

S1: performing preliminary desulfurization of molten iron by using a KR method to control the sulfur content at no more than 0.01%. Because sulfur element as an impurity element would reduce mechanical properties and corrosion resistance performance of steel and normally cannot be removed in a convertor, therefore, in order to reduce the sulfur content in steel, preliminary desulfurization treatment needs to be performed in molten iron. Before performing desulfurization, the blast furnace slag needs to be removed in order t...

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Abstract

The present invention relates to a steel rebar comprising the following ingredients: 0.005%-0.030% of C, 0.3%-0.6% of Si, 1.2%-2.5% of Mn, 0.01% or less of P, 0.01% or less of S, 8.0%-10.0% of Cr, 1.0%-3.0% of Mo, 0.2%-0.4% of Sn, 0.01%-0.05% of Rare Earth element, and the remainder being Fe and unavoidable impurities. The present invention also provides a production method of steel rebar. The steel rebar of the present invention has excellent comprehensive mechanical properties and corrosion resistance performance, while meeting the requirements of anti-knock, the service life in sea water of the steel rebar is increased, thus it can be widely used in reinforced concrete structures in ocean environment.

Description

TECHNICAL FIELD[0001]The present invention relates to a steel rebar and a production method thereof, which pertains to the field of alloy steel.BACKGROUND OF THE INVENTION[0002]Along with consciousness enhancing of ocean strategy of various countries and development of modern ocean science and technology, constructions of infrastructure such as huge cross-river or cross-sea bridges, seaport wharfs, and offshore buildings are entering into a peak season. Meanwhile, the durability problem of steel rebar used as a main structural material becomes increasingly prominent. The ocean environment is a relatively harsh corrosion environment in the nature, with its special conditions of high temperature, high humidity, and high salinity easily causing corrosion of steel. Severe corrosion usually occurs in the reinforced concrete structures along the coast of China after 10-15 years on service, which results in damage to the structures, rendering the structures unable to meet their designed se...

Claims

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Application Information

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IPC IPC(8): C21D9/52C22C38/28C22C38/24C22C38/22C22C38/04C22C38/02C22C38/00C21D8/06C21C7/064C21C7/06C21C7/068C21C7/10C21C5/28B22D11/00C22C38/38
CPCC21D9/525C21D2211/005C22C38/28C22C38/24C22C38/22C22C38/04C22C38/02C22C38/008C22C38/005C22C38/004C22C38/002C21D8/065C21C7/064C21C7/06C21C7/068C21C7/10C21C5/28B22D11/001C21D2211/002C22C38/38C21D8/08C21C1/02C21C5/30C22C38/18C22C38/60
Inventor ZHANG, JIANCHUNMA, HANHUANG, WENKELI, YANGZUO, LONGFEI
Owner INST OF RES OF IRON & STEEL JIANGSU PROVINCE
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