CN102605255A

CN102605255A - 400Mpa grade corrosion resistant reinforcing steel bar

Info

Publication number: CN102605255A
Application number: CN2012100177248A
Authority: CN
Inventors: 周新龙; 徐志; 范植金; 陈惠安
Original assignee: Wuhan Iron and Steel Group Corp
Current assignee: Wuhan Iron and Steel Group Corp
Priority date: 2012-01-19
Filing date: 2012-01-19
Publication date: 2012-07-25

Abstract

The invention relates to a 400Mpa grade corrosion resistant reinforcing steel bar, which comprises the components of 0.1-0.25% of C, 0.5-0.90% of Si, 0.7-1.5% of Mn, 0.04-0.09% of P, less than or equal to 0.015% of S, 0.3-0.6% of Cu, 0.1-0.4% of Ni, less than or equal to 0.1% of Cr, 0.03-0.08% of V, and the balance of Fe and inevitable impurities by weight. Compared with the normal construction steel in prior arts, the corrosion resistance in the marine environment of the reinforcing steel bar provided by the invention is remarkably improved, and according to a laboratory test, the corrosion resistance of Cl ion is more than two times of a normal reinforcing steel bar; compared with an epoxy resin coated reinforcing steel bar, the corrosion resistance of the reinforcing steel bar provided by the invention is superior, because the epoxy resin coated reinforcing steel bar is liable to surface spalling and corrosion rate is large after spalling; and compared with a reinforcing stainless steel bar, the production cost of the reinforcing steel bar provided by the invention is greatly reduced.

Description

A kind of 400Mpa level corrosion-resistant steel bar

Technical field

The present invention relates to ferrous materials, specifically belong to corrosion-resistant steel bar and working method thereof.

Background technology

High strength anti ocean environment corrosion reinforcing bar is applied in the skeleton construction under ocean environment or the chloride ion corrosion condition.The ocean is a corrosive environment the harshest in the Nature, because the seepage failure of cl ions very easily makes steel generation local corrosion, the local erosion depth spot of common iron can reach more than annual 2～4mm, the life-span and the safety that are greatly threatening maritime works's facility.Damage because chloride erosion causes the concrete structure that steel bar corrosion causes, be acknowledged as the major cause of coastal engineering destroying concrete structure.

At motorway, stride the situation of the chlorine salt corrosion Steel Concrete that takes place in the Infrastructure such as river sea large bridge and sea port dock, caused showing great attention to of scientific and engineering circle expert and government department.The U.S. finds in the investigation of nineteen ninety-five, the corrosion failure of reinforcing bar in the Infrastructure, and the year financial loss that causes reaches 1,500 hundred million dollars, accounts for more than 40% of total corrosion loss, calculates by GDP to reach 1～3%.China's investigation result in 2003, about 5,000 hundred million yuan of the total corrosion loss of steel, if calculate with reference to the practical experience of external reinforcement corrosion, China is because the loss in 1 year of reinforcement corrosion is approximately 2,200 hundred million yuan.

Durability Design and control techniques thereof is important in the above-mentioned example explanation infrastructure construction.For reaching 50 years weather resistance of offshore concrete structure that design construction standard requires, must pay attention to the problem of cl ions erosion damage concrete structure under the ocean environment.Prevent that at present the method that reinforcement corrosion is adopted from comprising coated reinforcement and stainless reinforcing bar; Document (Shinobu Tmaki; Advance in Corrosion Protection and Its Material; Nippon Steel Technical Report No.87January 2008 etc.) show that states such as the U.S. and Japan prevent that at present the method for reinforcement corrosion from also all adopting coated reinforcement and stainless reinforcing bar.Coated reinforcement such as epoxy coating reinforcing bar or galvanizing steel are subject to galled spots influence and produce heavy corrosion, can't satisfy the requirement of important engineering.Stainless reinforcing bar favorable anti-corrosion effect, but, cause production cost high owing to contain a large amount of alloying elements, also should not use in enormous quantities.

Therefore, be badly in need of the moderate high-strength corrosion-resistant steel bar product of cost of development.This also is the difficult scientific problems that the world steel interface is faced.

Summary of the invention

The problem that the present invention will solve is; Overcome the deficiency that present coated reinforcement that is adopted and stainless reinforcing bar exist; Provide a kind of, the corrosion-resistant steel bar and the working method thereof of the 400Mpa level intensity that in the corrosion resistance nature that improves reinforcing bar, reduces cost through Alloying Treatment.

Realize the measure of above-mentioned purpose:

400Mpa level corrosion-resistant steel bar, its component and weight percent are: 0.1%～0.25%, Si:0.5%～0.90%; Mn:0.7%～1.5%, P:0.04%～0.09%, S≤0.015%; Cu:0.3%～0.6%, Ni:0.1%～0.4%, Cr≤0.1%; V:0.03%～0.08%, surplus is Fe and unavoidable impurities.

The present invention compares with existing common structural steel, and its corrosion resistance in ocean environment increases significantly, and through laboratory test, its anti-Cl ion etching ability is more than 2 times of regular reinforcement; With the epoxy coating reinforcement ratio, because the epoxy coating rebar surface be prone to produce peeling phenomenon, and it is bigger to peel off post-etching speed, and both compare, anti-excellent corrosion of the present invention; Comparing then with stainless reinforcing bar, production cost can significantly reduce.

Embodiment

Describe in detail in the face of the present invention down:

Test one (being laboratory test)

Present embodiment has been smelted 13 stoves test steel and 2 stove compared steel in the 50kg vacuum induction furnace, its composition is seen table 1.

And according to following production stage, roll out heating rolling and become the thick steel plate of 20mm, as the raw material of processing reinforcing bar.

Production technique is carried out according to following conventional steps:

1) smelt, the control tapping temperature is at 1650 ℃～1680 ℃;

2) carry out refining, continuous casting, the superheating temperature of control continuous casting tundish is at 15 ℃～30 ℃;

3) to the strand heating, control its Heating temperature at 1150 ℃～1250 ℃;

4) be rolled, control its finishing temperature≤950 ℃;

5) naturally cool to room temperature;

6) carry out finishing, packing, and for use.

Table 1 test composition of steel (weight percent)

Contrast 1 is the Cr of test steel adding 1.23%, with the disadvantageous effect of checking Cr to corrosive nature; Contrast 2 is industrial common 400MPa grade reinforcing steel product.

Table 2 is for carrying out the results list of mechanical property and corrosion test to test steel one.

Its test conditions: test steel and compared steel detect performance through being machined into tension specimen; Being processed into etched sheet carries out week soaking corrosion test; 45 ± 2 ℃ of testing liquid: 3%NaCl, test temperatures; Relative humidity 70 ± 5% was soaked wheel speed 1 circle week/60 minutes, and etching time is respectively 288 hours (corrosion rate 1) and 216 hours (corrosion rate 2).

The mechanical property of table 2 test one steel and the results list of corrosion test

Visible by table 2, the steel of all the components all reaches the performance requriements of 400MPa grade reinforcing steel, and the corrosion rate of the examination steel in the design mix scope contrasts steel grade and reduces more than 60%.

Test two (for commerical test)

Present embodiment has been smelted 1 stove test steel and 2 stove compared steel in converter smelting, its composition is seen table 3.

And, roll out the Twisted Steel of Φ 28mm according to following production stage.

Production technique is seen:

Table 3 test composition of steel (weight percent)

Table 4 is the main production parameter of test two steel.

Table 4 is the main production parameter of test two steel

Test steel heat (batch) number	Tapping temperature ℃	Tundish superheating temperature ℃	Slab heating temperature ℃	Finishing temperature ℃
					14	1670～1675	28	1150℃～1200℃	870℃
Contrast 3	1670～1675	28	1180℃～1220℃	910℃

[0039]

Contrast 4

1670～1675

28

1200 ℃～1250 ℃

940 ℃

Table 5 is the mechanical property and the corrosion test result of test two steel.

The mechanical property and the corrosion test result of table 5 test two steel

Through carrying out welding test to testing a steel with test two steel, postwelding tension test cleaved position all on mother metal, explains that welding property is good.

Claims

1.400Mpa the level corrosion-resistant steel bar, its component and weight percent are: 0.1%～0.25%, and Si:0.5%～0.90%; Mn:0.7%～1.5%, P:0.04%～0.09%, S≤0.015%; Cu:0.3%～0.6%, Ni:0.1%～0.4%, Cr≤0.1%; V:0.03%～0.08%, surplus is Fe and unavoidable impurities.