CN1386886A

CN1386886A - Rare-earth alloy steel resisting dew point corrosion of sulfuric acid

Info

Publication number: CN1386886A
Application number: CN 01119592
Authority: CN
Inventors: 束润涛
Original assignee: Individual
Current assignee: Individual
Priority date: 2001-05-23
Filing date: 2001-05-23
Publication date: 2002-12-25

Abstract

A rare-earth alloy steel resisting dew point corrosion of sulfuric acid is prepared from Cu, W, Sn, rare-earth element, Mo and Sb. Its advantage is high resistance to dew point corrosion of sulfuric acid.

Description

The rare earth alloy steel of sulfuric acid dew point corrosion resistant

The present invention relates to the steel for resisting sulfuric acid dew point corrosion of oil, chemical industry, power system.

At present at home and in the steel for resisting sulfuric acid dew point corrosion that is abroad using, it generally all is the component prescription that with Cr-Cu-Sb (Sn), as the U.S. and the Japanese main trade mark that in the boiler preheating device, uses COR-TEN, NAC-2B, NAC-2C etc. are arranged, and the ND steel of the emerging clear steel mill in Chinese Jiangyin, being 09CrCuSb, all is the alloy thinking of Cr-Cu-Sb (Sn).In the mentioned component design,,, the cycling processability of steel is affected because Sb and Sn occur with the impurity form in the steel though taken into full account the alloy proportion of corrosion-resistant elemental composition.Chinese patent: 89109017.7, CN:1052150A though consider to use rare earth (RE), has save patience H in the design of Cr-Cu set member ₂SO ₄Sb and Sn that can be good, its corrosion resistance nature be not very good.

In the device of industries such as oil, chemical industry, electric power, sulfuric acid dew point corrosion generally appears at boiler preheating device and economizer equipment, and on line of pipes and the chimney.All contain a large amount of sulphur (S) in fuel that boiler is used such as heavy oil and the coal, become sulfurous gas (SO through combustion decomposition ₂), wherein a part also can regeneration sulfurous gas (SO ₂), sulphur trioxide (SO ₃) combine with water vapor at dew-point temperature (150 ℃) position and to become sulfuric acid (H ₂SO ₄), thicken by rare, thus equipment is constituted the intensive corrosion.

The present invention is by following scheme implementation:

The present invention mainly is by formations such as carbon, silicon, manganese, phosphorus, sulphur in copper (Cu), tungsten (W), molybdenum (Mo), tin (Sn), antimony (Sb), rare earth (RE) and the steel, and surplus is by iron balance in addition, its chemical ingredients following (%):

??C	????Si	????Mn	????Cu	????W	????Mo	????Sn	????Sb	RE (add-on)	??S	??P
??C	????Si	????Mn	????Cu	????W	????Mo	????Sn	????Sb	RE (add-on)	??S	??P	≤0.15	????0.15～ ????1.20	????0.30 ????～1.50	????0.20 ????～0.80	????0.10 ????～0.60	????0.10 ????～0.50	????0.05～ ????0.30	????0.05 ????～0.30	???≤0.50	??≤ ??0.035	??≤ ??0.035

In this composition design, Cu and S are in conjunction with generating the CuS compound on the surface, to resist rare H ₂SO ₄Corrosion, but sulphur (S) should be controlled between 0.010～0.035%; The adding of Sn and Sb is also to stoping rare H ₂SO ₄Corrosion play obvious effect; The Cu-W-Mo combination is to anti-dense H ₂SO ₄Corrosion play obvious effect, W and Mo add with the compound form, can also improve the heat resistance of steel; The inclusion morphology of Sn and Sb in main control steel of rare earth (RE) is to improve the impelling strength and the corrosion resistance nature of steel.Rare earth (RE) not only has great affinity interaction to low melting point metal in the steel and nonmetal composition, and the ability of extremely strong desulfurization and deoxidation is arranged, and can obviously improve the welding property of steel.Rare earth (RE) ratio relation of residue and sulphur in steel is: RE/S=1～6, its best ratio relation should be controlled between 2～4.

Embodiment:

Chemical ingredients following (%):

??C	??Si	??Mn	??Cu	??W	??Mo	??Sn	??Sb	RE (add-on)	??S	??P
??C	??Si	??Mn	??Cu	??W	??Mo	??Sn	??Sb	RE (add-on)	??S	??P	??≤ ??0.12	??0.20 ??-0.50	??0.30 ??-0.80	??0.20 ??-0.50	??0.10 ??-0.25	??0.10 ??-0.20	??0.05 ??-0.20	??0.05 ??-0.20	??0.10 ??-0.15	??0.010 ??-0.035	??≤ ??0.030

The present invention can use open hearth and electrosmelting, also can be with external refining with the further performance of improving steel.Rare earth should add in the process of coming out of the stove or in the ladle after the tapping.The smelting process of smelting process of the present invention and other low alloy steel is basic identical, implements simple.With the steel of this composition design can rolled plate, tubing, section bar, can also be with steel billet or round bar forging material.

The present invention is because the Cu-W-Sn-RE (Mo, Sb) of use tungsten (W) replacement chromium (Cr) is the alloy thinking, and added rare earth element, the corrosion resisting property and the welding property of material are improved in a large number, simultaneously rare earth improves impelling strength and has improved the cold-forming property of material, can be widely used in the devices such as chimney, boiler economizer, air preheater of industries such as oil, chemical industry, electric power.

Claims

1. the rare earth alloy steel of a sulfuric acid dew point corrosion resistant, it is that low-alloy by copper (Cu), tungsten (W), tin (Sn), rare earth (RE) and molybdenum (Mo) and antimony (Sb) becomes branch to constitute, and it is characterized in that the chemical ingredients of its described Cu-W-Sn-RE (Mo, Sb) consists of (% of weight than):

C≤0.15???????????Si：0.15～1.20??????Mn：0.30～1.50???Cu：0.20～0.80

W：0.10～0.60?????Mo：0.10～0.50??????Sn：0.05～0.30???Sb：0.05～0.30

RE (add-on)≤0.50 S :≤0.035 P :≤0.035 surplus is by iron (Fe) balance in addition.

2. as claims 1 described rare earth alloy steel, it is characterized in that: its described Cu-W-Sn-RE (Mo, Sb) is that steel alloy can be made sheet material, tubing, section bar and forging.

3. as claims 1 described rare earth alloy steel, it is characterized in that: the ratio relation of the residue of its described steel middle-weight rare earths (RE) and sulphur (S) is RE/S=1～6.