CN102877002A

CN102877002A - Heat resistant steel for boiler parts and manufacture method of heat resistant steel

Info

Publication number: CN102877002A
Application number: CN2012104206201A
Authority: CN
Inventors: 章磊
Original assignee: Individual
Current assignee: Individual
Priority date: 2012-10-24
Filing date: 2012-10-24
Publication date: 2013-01-16

Abstract

The invention relates to heat resistant steel for boiler parts. On the basis of the traditional heat resistant steel, elements such as Zr, Hf, Ta and Al are added, elements such as V and Co are reduced, the content of Cr is lowered, the manufacture method is improved, different chemical elements are added in batches and secondary tempering and annealing are carried out under special conditions, therefore, the boiler parts have high-temperature durability and the creep property at a temperature of 960 DEG C and above, and have better corrosion resistance and oxidization resistance.

Description

A kind of high temperature steel for the boiler component and preparation method thereof

Technical field

The present invention relates to a kind of high temperature steel, especially a kind of high temperature steel for the boiler component and preparation method thereof.

Background technology

Development along with prior art, in order further to increase the work-ing life of boiler component, increase the power of boiler, further improved furnace temperature, in this case, selecting a kind ofly just becomes the task of top priority at 960 degree and the above material that still has high temperature resistant persistence and creep properties thereof, and high temperature steel of the prior art with this understanding high temperature resistant persistence and creep properties all can significantly reduce, and erosion resistance and oxidation-resistance are lower.

Summary of the invention

The invention provides a kind of high temperature steel for the boiler component, form and making method by specific chemical element, make the boiler component at 960 degree and when above, still have good high temperature durability and creep properties, and erosion resistance and oxidation-resistance are fine.

The present invention has added the elements such as Zr, Hf, Ta, Al on the basis of existing high temperature steel, the elements such as V, Co have been reduced, reduced the content of Cr, improved making method, add in batches different chemical elements and carry out under given conditions double tempering and annealing, improve by this, make the boiler component have good high temperature durability and creep properties at 960 degree and when above under the condition, and have good erosion resistance and oxidation-resistance.

The invention provides a kind of high temperature steel for the boiler component, it is characterized in that: the chemical constitution of described steel is below to be all weight percent:

C：0.02-0.4，Ta：0.8-1.0，Nb：0.2-0.3，W：2.5-3.8，N：0.1-0.2，B：0.02-0.04，Si：0.2-0.4，Cu：0.6-0.7，Al：0.2-0.23，Ni：2.2-3.2，Cr：2.6-4.8，Zr：1.9-2.7，Hf：0.3-0.6，Mn：0.4-0.9，Mo：2.0-3.0，

Surplus is Fe and impurity thereof, wherein 8: 1 〉=Zr: Hf 〉=5: 1,3.5: 1 〉=Cu: Al 〉=3: 1, Zr+Hf+Ta+Nb+Ni 〉=6.0.

Preferred scheme is content of impurities≤0.1.

Preferred scheme is in the impurity:

P≤0.01，S≤0.01，Zn≤0.005，Sb≤0.01。

Preferred scheme is for also comprising Re, and Re content is 0.1-0.4.

Preferred scheme is that Re is Ce and Y, Ce: Y 〉=3: 1.

The present invention also provides a kind of making to be used for the method for the high temperature steel of boiler component, mainly is comprised of following steps:

(1) with cast iron just refining in non-vacuum induction furnace, when treating that cast iron begins to melt, adds W, Zr, Hf, Nb, Ta, the Ni element when cast iron melts fully, adds Si, Cu, Mn, Mo, B, Cr, Al, cast iron melts adding C and N after 30 minutes fully, and the ratio of regulating each element, C:0.02-0.4, Ta:0.8-1.0, Nb:0.2-0.3, W:2.5-3.8, N:0.1-0.2, B:0.02-0.04, Si:0.2-0.4, Cu:0.6-0.7, Al:0.2-0.23, Ni:2.2-3.2, Cr:2.6-4.8, Zr:1.9-2.7, Hf:0.3-0.6, Mn:0.4-0.9, Mo:2.0-3.0, surplus is Fe and impurity thereof, wherein 8: 1 〉=Zr: Hf 〉=5: 1,3.5: 1 〉=Cu: Al 〉=3: 1, Zr+Hf+Ta+Nb+Ni 〉=6.0, solution casting becomes consumable electrode;

(2) with consumable electrode remelting refining in electroslag furnace, further the content of impurity reduction element makes it meet design requirements, makes ESR ingot;

(3) ESR ingot is made the boiler component, whirlpool boiler component are carried out anneal, treatment step and processing parameter are:

The boiler component are heated to 1250 degree, are incubated after 6 hours, insulation 800 degree are incubated 24 hours in annealing furnace, are cooled to normal temperature, further are heated to 950 degree, are incubated after 3 hours, and insulation 750 degree are incubated 8 hours in annealing furnace, are cooled to normal temperature.

Preferred scheme is impurity element total content≤0.1.

Preferred scheme is in the impurity element:

P≤0.01，S≤0.01，Zn≤0.005，Sb≤0.01。

Preferred scheme is in the step (1), when cast iron melts fully, also be added with Re, and Re content is 0.1-0.4.

Preferred scheme is that Re is Ce and Y, Ce: Y 〉=3: 1.

Sample of the present invention process under 960 degree conditions detects:

Yield strength σ 0.02 〉=630N/mm2

Tensile strength sigma b 〉=930N/mm2

Elongation δ 〉=10%

Relative reduction in area ψ 〉=43%

Ballistic work AKv 〉=40J

Sample of the present invention is 960 degree in temperature, and stress is that process detects under the 200N/mm2 condition:

Rupture time (Hr) 〉=135 hour.

Of the present inventionly detect by the salt mist experiment method: 10%NaCl, temperature 960 degree, under the PH7.2-7.4 condition, carry out continuously spraying experiment in seven days, product surface of the present invention is smooth, glossy, without rust spot.

The high temperature steel that is used for the boiler component that the present invention makes by specific chemical constitution and manufacture craft under 960 degree temperature, has good high-temperature and durable and creep properties, and has good erosion resistance and oxidation-resistance.

Embodiment

Below the present invention is further detailed explanation.

Embodiment 1

Following table is five samples, and the content of chemical element is as follows in each sample:

Prescription	C	Cr	Zr	Hf	Ta	Nb	Mn	Mo	W	N	B	Si	Cu	Ni	Al
																Sample 1	0.03	2.6	1.9	0.3	0.8	0.3	0.4	2.3	2.6	0.2	0.02	0.2	0.7	2.4	0.2
Sample 2	0.05	4.2	2.6	0.4	0.9	0.2	0.7	3.0	2.5	0.15	0.03	0.4	0.6	2.6	0.2
																Sample 3	0.1	4.6	2.7	0.5	1.0	0.3	0.9	2.4	2.9	0.17	0.04	0.4	0.7	3.2	0.22
Sample 4	0.2	2.6	2.6	0.5	0.8	0.2	0.4	2.5	3.8	0.16	0.03	0.3	0.6	2.8	0.2
																Sample 5	0.4	4.8	2.3	0.3	0.9	0.2	0.5	2.8	3.6	0.18	0.02	0.3	0.7	3.0	0.21

Under 960 degree conditions, pressure is 18MPa to sample 1-5, and stress is 200N/mm ²Condition under detect, the result is as follows:

	σ _0.02	σ _b	δ	ψ	AKv	Hr
							Sample 1	632	932	14	43	42	136
Sample 2	646	945	13	46	44	138
							Sample 3	689	968	12	53	48	142
Sample 4	673	979	14	51	43	143
							Sample 5	631	941	11	52	45	137

By the above results and contrast, can learn, product high temperature durability of the present invention and creep properties all are significantly improved, especially under 960 degree working conditions.

Embodiment 2

The present embodiment verifies that mainly the ratio of Cu, Al on the impact of its performance, reconciles the ratio of Cu, Al on the basis of sample 4, is labeled as standard specimen, sample 41, sample 42, sample 43, sample 44, sample 45, sample 46,47,48:

Prescription	C	Cr	Zr	Hf	Ta	Nb	Mn	Mo	W	N	B	Si	Cu	Ni	Al
																Standard specimen	0.2	2.6	2.6	0.5	0.8	0.2	0.4	2.5	3.8	0.16	0.03	0.3	0.6	2.8	0.2

Sample 41	0.2	2.6	2.6	0.5	0.8	0.2	0.4	2.5	3.8	0.16	0.03	0.3	0.2	2.8	0.1
																Sample 42	0.2	2.6	2.6	0.5	0.8	0.2	0.4	2.5	3.8	0.16	0.03	0.3	0.4	2.8	0.15
Sample 43	0.2	2.6	2.6	0.5	0.8	0.2	0.4	2.5	3.8	0.16	0.03	0.3	0.5	2.8	0.18
																Sample 44	0.2	2.6	2.6	0.5	0.8	0.2	0.4	2.5	3.8	0.16	0.03	0.3	0.7	2.8	0.23
Sample 45	0.2	2.6	2.6	0.5	0.8	0.2	0.4	2.5	3.8	0.16	0.03	0.3	0.8	2.8	0.25
																Sample 46	0.2	2.6	2.6	0.5	0.8	0.2	0.4	2.5	3.8	0.16	0.03	0.3	0.9	2.8	0.3
Sample 47	0.2	2.6	2.6	0.5	0.8	0.2	0.4	2.5	3.8	0.16	0.03	0.3	0.6	2.8	0.23
																Sample 48	0.2	2.6	2.6	0.5	0.8	0.2	0.4	2.5	3.8	0.16	0.03	0.3	0.6	2.8	0.21

Under 960 degree conditions, pressure is 18MPa to sample 41-48, and stress is 200N/mm ²Condition under detect, the result is as follows:

	σ _0.02	σ _b	δ	ψ	AKv	Hr
							Standard specimen	673	979	14	51	43	143
Sample 41	672	973	12	52	42	112
							Sample 42	675	972	11	49	46	116
Sample 43	671	969	15	47	44	118
							Sample 44	673	980	16	53	45	142
Sample 45	674	979	14	51	46	143
							Sample 46	670	981	14	51	40	121
Sample 47	672	983	15	54	40	122
							Sample 48	676	975	13	52	43	124

By the above results and contrast, can learn, at Cu content at 0.6-0.7, and Al content between 0.2-0.23 and 3.5: 1 〉=Cu: Al 〉=3: 1 o'clock, rupture time is the longest, otherwise the rupture time can affect its high temperature the time.

By above similar experiment, detect proof Zr content 1.9-2.7, Hf content 0.3-0.6, and 8: 1 〉=Zr: Hf 〉=5: 1 o'clock, tensile strength is best under hot conditions.

By above similar experiment, detect proof Ta content 0.8-1.0, Nb content 0.2-0.3, Ni content 2.2-3.2, Zr content 1.9-2.7, Hf content 0.3-0.6, and Zr+Hf+Ta+Nb+Ni 〉=6.0, its elongation and relative reduction in area are best.

Embodiment 3

The main checked for impurities of the present embodiment adds respectively following impurity to the impact of its characteristic on the basis of sample 3, be labeled as sample 31, sample 32, and sample 33:

	P	S	Zn	Sb
					Sample 31	0.01	0.01	0.005	0.01
Sample 32	0.02	0.02	0.012	0.02
					Sample 33	0.02	0.02	0.030	0.02

Under 960 degree conditions, pressure is 18MPa to sample 31-33, and stress is 200N/mm ²Condition under detect, the result is as follows:

	σ _0.02	σ _b	δ	ψ	AKv	Hr
							Sample 31	689	968	12	53	48	142
Sample 32	672	892	10	49	42	134
							Sample 33	662	632	8	42	36	112

By above result, can learn, in P≤0.01, S≤0.01, Zn≤0.005 in the situation of Sb≤0.01, does not basically affect performance, otherwise will have a strong impact on performance, especially in the situation that the Zn increase.

Embodiment 4

The present embodiment Re (rare earth element) adds respectively following impurity to the impact of its characteristic on the basis of sample 1, be labeled as sample 11, sample 12, and sample 13:

	Rare earth (total amount)	Ce	Y	Other rare earth element
					Sample 11	0.04	Arbitrarily	Arbitrarily	Contain
Sample 12	0.04	0.03	0.01	Do not contain
					Sample 13	0.04	0.01	0.03	Do not contain

Under 960 degree conditions, pressure is 18MPa to sample 11-13, and stress is 200N/mm ²Condition under detect:

	σ _0.02	σ _b	δ	ψ	AKv	Hr
							Sample 11	646	962	15	46	48	143
Sample 12	683	999	18	51	54	156
							Sample 13	651	962	14	43	47	145

By above result, can learn, add Re, can improve the performance of sample, especially add Ce and Y, particularly Ce: Y 〉=3: 1 o'clock, performance is better.

Embodiment 5

On the basis of sample 2, make by diverse ways, be designated as respectively sample 21, sample 22, sample 23, sample 24:

Ordinary method of the present invention is with cast iron just refining in non-vacuum induction furnace, and after cast iron dissolved fully, all chemical elements of disposable adding were reconciled the content of each element, make consumable electrode; And carry out the electroslag furnace remelting refining, and make turbine component, be the melting method of sample 21;

On the basis of ordinary method, when treating that cast iron begins to melt, add W, Zr, Hf, Nb, Ta, the Ni element, when cast iron melts fully, add Si, Cu, Mn, Mo, B, Cr, Al, cast iron melts adding C and N after 30 minutes fully, and solution casting becomes consumable electrode to be the melting method of sample 22;

On the basis of ordinary method, the boiler component are heated to 1250 degree, are incubated after 6 hours, insulation 800 degree in annealing furnace, be incubated 24 hours, be cooled to normal temperature, further be heated to 950 degree, be incubated after 3 hours, insulation 750 degree in annealing furnace, be incubated 8 hours, be cooled to normal temperature, be the melting method of sample 23;

On the basis of ordinary method, when treating that cast iron begins to melt, add W, Zr, Hf, Nb, Ta, the Ni element is when cast iron melts fully, add Si, Cu, Mn, Mo, B, Cr, Al, cast iron melts fully after 30 minutes and to add C and N,, and the boiler component are heated to 1250 degree, be incubated after 6 hours, insulation 800 degree are incubated 24 hours in annealing furnace, are cooled to normal temperature, further be heated to 950 degree, be incubated after 3 hours, insulation 750 degree are incubated 8 hours in annealing furnace, be cooled to normal temperature, be the melting method of sample 24.

	σ _0.02	σ _b	δ	ψ	AKv	Hr
							Sample 21	588	893	11	39	39	116
Sample 22	611	903	13	42	42	125
							Sample 23	601	912	13	41	40	123
Sample 24	673	979	14	51	43	143

Can learn by above result, add in batches different chemical elements, and carry out second annealing and process, can improve the performance of product.

Above content be in conjunction with structure of the present invention and working process to its further description of doing, can not assert that implementation of the present invention is confined to these explanations.For the general technical staff of the technical field of the invention, without departing from the inventive concept of the premise, can also make some simple deduction or replace, all should be considered as belonging to protection scope of the present invention.

Claims

1. high temperature steel that is used for the boiler component, it is characterized in that: the chemical constitution of described steel is below to be all weight percent:

2. the high temperature steel for the boiler component according to claim 1 is characterized in that: described content of impurities≤0.1.

3. the high temperature steel for the boiler component according to claim 2 is characterized in that: in the described impurity:

P≤0.01，S≤0.01，Zn≤0.005，Sb≤0.01。

4. usefulness according to claim 1 is used for the high temperature steel of boiler component, and it is characterized in that: also comprise Re, Re content is 0.1-0.4.

5. the high temperature steel for the boiler component according to claim 4, it is characterized in that: described Re is Ce and Y, Ce: Y 〉=3: 1.

6. a making is used for the method for the high temperature steel of boiler component, mainly is comprised of following steps:

7. making according to claim 6 is used for the method for the high temperature steel of boiler component, it is characterized in that: described impurity element total content≤0.1.

8. making according to claim 7 is used for the method for the high temperature steel of boiler component, it is characterized in that: in the described impurity element:

P≤0.01，S≤0.01，Zn≤0.005，Sb≤0.01。

9. making according to claim 6 is used for the method for the high temperature steel of boiler component, it is characterized in that: in the described step (1), when cast iron melts fully, also be added with Re, and Re content is 0.1-0.4.

10. making according to claim 9 is used for the method for the high temperature steel of boiler component, and it is characterized in that: described Re is Ce and Y, Ce: Y 〉=3: 1.