CN1143003C - Calorized trinickel based heat resistance alloy - Google Patents

Abstract

An Ni<3>Al-base heat-resistant alloy containing, in % by weight, 6.0 to 9.0% of Al, 2.0 to 15.0% of Cr and 0.5 to 3.0% of Zr, the balance being Ni and inevitable impurities, the alloy having a metal structure comprising Ni3Al as the main phase thereof. When required, the alloy may further contain over 0% to not more than 5.0% of W, over 0% to not more than 3.0% of Mo, over 0% to not more than 3.0% of Nb, over 0% to not more than 0.003% of B, over 0% to not more than 0.3% of C and 0.003 to 0.03% of N, wherein the combined amount of W, Mo and Nb is up to 5.0% if at least two of these elements are present.

Description

Calorized trinickel based heat resistance alloy

The calorized trinickel based heat resistance alloy of the present invention relates to have required hot strength (tensile strength and yield strength) and good creep-rupture strength and weldability.

Calorize three nickel (Ni ₃Al) be the property that intermetallic compound (about 1390 ℃ of fusing point) with face-centered cubic crystal structure and the yield strength that has exosyndrome material intensity raises and increase with temperature.

Since this performance, Ni ₃The Al based heat resistant alloy promptly contains disperse Ni wherein ₃The alloy that Al separates out, it can keep a high stress level in the pyritous temperature range.The Ni of Ti Chuing so far ₃The Al based heat resistant alloy is as described below.

The open 62-93334 of Japanese unexamined discloses a kind of alloy, it comprises (atom %): IVb family element (Zr or Hf) 0.2-1.5%, Al 17-20%, Cr 4.5-8%, B 0.05-0.2%, Fe 9-16%, rare earth element (as Ce) 0.001-0.004% and Ni surplus, it has improved hot strength, plasticity and hot workability.

The open 63-66374 of Japan's authorization discloses a kind of Ni-Al alloy, and it mainly comprises Ni ₃Al, it comprises (weight %): Mo 0.01-2.0%, B 0.05-3.0%, Zr 0.5-4.0% etc., and improved temperature-room type plasticity and intensity.

The open 63-266036 of Japanese unexamined discloses a kind of Ni base alloy, and it has Ni ₃Al is the metal structure of principal phase, and it contains (atom %): Ni 75.4-79%, and Al 7-12%, B≤0.5%, C≤0.9%, Hf 0.5-4%, Fe 4.5-11%, Mo, W, Nb or Zr≤3%, and improved temperature-room type plasticity, intensity etc.

The open 4-501440 of Japanese national phase discloses a kind of alloy, and it comprises (atom %): Al 5-18.5%, and Cr 6-10%, Zr 0.05-0.35%, B 0.08-0.30% and Ni surplus, and improved high-temp plastic, processibility and intensity.

Japanese Patent No.2599263 discloses a kind of Ni-Al alloy, and it comprises the Ni as principal phase ₃Al, it comprises (weight %): IVb family element (Hf or Zr)＜1%, Fe 14.5-17.5%, rare earth element (as Ce, Y or La)≤0.01%, B 0.01-0.05% and Mo≤4%, and improved processibility.

But, because Ni ₃Al does not almost have unit elongation, common Ni ₃The Al based heat resistant alloy has the problem that creep-rupture strength obviously weakens at the high temperature range that surpasses 1050 ℃, so, from the intensity viewpoint, be restricted in the high temperature use.

Also because intermetallic compound Ni ₃Al is to the hypersensitivity of welding crack, and this alloy is not suitable for the structure that needs welding assembly.Like this, common alloy is restricted as refractory alloy.

That considers the problems referred to above the present invention seeks to be provided at the Ni that the high temperature range that surpasses 1050 ℃ has high creep-rupture strength and superior weldability ₃The Al based heat resistant alloy.

Refractory alloy provided by the invention comprises (weight %): Al 6.0-9.0%, and Cr 2.0-15.0%, Zr0.5-3.0%, surplus is Ni and unavoidable impurities, this alloy has with Ni ₃The metal structure that Al constitutes as its principal phase.

Expression " Ni used herein ₃Al is as principal phase " mean that in principal phase be Ni in the metal structure of Ni sosoloid ₃The ratio of Al (volume) is greater than 50%.For guaranteeing required hot strength (yielding stress and tensile strength), Ni ₃The ratio of Al (volume) preferably at least 70%.

When needs, can add W greater than 0% to being not more than 5.0% in refractory alloy of the present invention, Mo is greater than 0% to being not more than 3.0%, Nb greater than 0% to being not more than 3.0%, B is greater than 0% to being not more than 0.003%, C greater than 0% to being not more than 0.3% and N 0.003-0.03%.When having W, Mo and Nb at least two kinds, the combined amount of these elements≤5.0%.

Preferably refractory alloy of the present invention comprises Al, Cr, Zr, W, B, C and/or N as effective element in corresponding scope, and surplus is essentially Ni.

Fig. 1 is the photo that shows the sample No.12 of the solderability test that comprises dye check.

Fig. 2 is the photo that shows the sample No.102 of the solderability test that comprises dye check.

Ni of the present invention₃The reasons are as follows of the component restriction of Al based heat resistant alloy.

In the narration below, percentage all is weight percentage.

Al：6.0-9.0％

Al forms intermetallic compound Ni with Ni₃The basic element of Al. If Al content is less than 6.0%, Ni₃The quantity not sufficient of Al can not provide the elevated temperature strength that needs. On the other hand, if this content greater than 9.0%, the creep rupture strength of alloy reduces. So Al content is 6.0-9.0%.

Cr：2.0-15.0％

Cr helps to improve high temperature tensile strength.When Cr content at least 2.0%, can obtain this effect.But, exist Cr to cause that hardness too increases greater than 15.0%, cause the temperature-room type plasticity infringement.For this reason, Cr content is 2.0-15.0%, preferred 4.0-8.0%.

Zr：0.5-3.0％

Zr is being effectively aspect the remarkable improvement weldability, because by Ni ₃Al is the hypersensitivity of the Ni based heat resistant alloy of principal phase formation to welding crack, and when welding, alloy is easy to produce welding crack.But, in substantially mutually, have Ni ₅During Zr form Zr, can improve anti-grain-boundary crack.At the high temperature that surpasses 1050 ℃, Zr also helps to improve intensity (tensile strength and yield strength) and creep-rupture strength.So, Zr at least 0.5%, preferably at least 1.0%.But, if Zr content greater than 3.0%, this effect does not increase, thereby this value is for the upper limit.

Refractory alloy surplus of the present invention is Ni and unavoidable impurities.For Ni of the present invention ₃The Al based heat resistant alloy, except S, P etc., impurity comprises, for example Fe.Because element of Fe infringement hot strength is so Fe content preferably is limited to minimum in alloy of the present invention.If Fe content surpasses 3.0%, will produce very important influence, so its content restriction is not more than 3.0%, better be not more than 1.0%.

When needs, following element can be joined Ni of the present invention ₃In the Al based heat resistant alloy.

W: greater than 0% to being not more than 5.0%

W is the effective element that improves creep rupture strength at high temperatures.But the excessive existence of this element not only reduces high temperature tensile ductility, and the infringement creep-rupture strength, reduces weldability simultaneously.So W content should be less than 5.0%, preferred 0.5-5.0%, more preferably 1.0-4.0%.

Mo, Nb: greater than 0% to being not more than 3.0%

As W, Mo and Nb also are the effective elements that improves creep rupture strength at high temperatures.So Mo and Nb can replace W or coexist with W.But as W, excessive Mo or Nb not only reduce high temperature tensile ductility, and the infringement creep-rupture strength, reduce weldability simultaneously.For this reason, Mo and Nb content are respectively less than 3.0%.

The effect of W, Mo and Nb is similar, so when using at least two kinds of these elements, the combined amount restriction of these elements is not more than 5.0%.

C: greater than 0% to being not more than 0.3%

When C and Cr existed jointly, the carbide of Cr was separated out and is strengthened crystal boundary at crystal boundary, has improved high-temp plastic.When having trace C, can obtain this effect.If C content surpasses 0.3%, the plasticity with infringement typical temperature scope reduces weldability simultaneously.So the restriction of C content is not more than 0.3%, preferred 0.1-0.2%.

N：0.003-0.03％

As C, N improves high-temp plastic, and when the N that has at least 0.003%, this effect occurs.Though content increases, effect strengthens,, the economy of N infringement alloy smelting production greater than 0.03%.So N content should be 0.003-0.03%, preferred 0.004-0.02%.B: greater than 0% to being not more than 0.003%

B improves plasticity and helps to improve creep rupture strength at high temperatures at grain boundary segregation.But the B greater than 0.003% causes welding crack sensibility to increase, and the grievous injury weldability.For this reason, B content should limit and be not more than 0.003%, preferred 0.001-0.002%.

Ni of the present invention ₃The metal structure of Al based heat resistant alloy comprises the Ni sosoloid as its matrix phase, and has principal phase Ni ₃Al and a small amount of and its blended Ni ₅The Zr precipitated phase.

Embodiment

Prepare sample by following step.

Use alumina crucible (internal diameter 145mm, high 256mm) in argon gas atmosphere, to smelt the production alloy by high frequency.At first,, Al is added among the Ni of fusing, and mixture heating up is arrived higher temperature by heat fused Ni.Then specific metallic element is added in the mixture, then adjusts temperature, the solution that obtains is injected ladle.Solution is that 16kg is heavy.

Below, use a metal pattern in atmosphere, to prepare tubulose sample (external diameter 137mm, wall thickness 19mm, long 270mm) by rotary casting.

The macrostructure of the tubulose sample of rotary casting comprises by the column crystal that directly is set in the outside with at the inboard local granular crystal that exists.

By the specific test specimen of each specimen preparation of such preparation, and carry out high-temperature behavior test, high temperature creep tearing test and solderability test.Carry out the high-temperature behavior test, check tensile strength, 0.2% yielding stress, unit elongation and relative reduction in area at 1100 ℃.Carry out the high temperature creep tearing test, be determined at 30MPa load down at 1100 ℃ creep fracture time.For solderability test, in its peripheral, axial test specimen is carried out the TIG welding by plate pearl (bead-on-plate) method (welding current 120A), after this with the naked eye carry out dye check.

Table 1 shows the chemical ingredients and the test-results of sample alloy.

Table 1

Sample No.	Alloy composition (surplus is Ni and unavoidable impurities) (wt%)										High-temperature behavior				Creep fracture time (Hrs)	Weldability
																	Tensile strength (MPa)	0.2% yielding stress (MPa)	Unit elongation (%)	Relative reduction in area (%)
											Al	Cr	Zr	W							Mo	Nb	C	N	B	Fe
	1	7.5	5.0	1.8	-	-	-	-	-	-																	0.09	158	95	25.9	30.6	90.2	○
2											7.5	2.5	1.0	2.5	-	-	-	-	-	0.90	233	139	5.1	5.1	70.2	○
	3	7.5	5.0	1.5	-	1.5	-	-	-	-																	0.10	194	116	21.2	44.7	69.3	○
4											7.5	5.0	1.8	-	-	1.0	-	-	-	0.10	245	127	3.2	3.4	66.0	○
	5	8.0	7.0	1.8	-	-	-	0.25	-	-																	0.10	191	110	9.4	11.7	71.4	○
6											8.0	6.5	1.8	-	-	-	-	0.0045	-	0.10	201	114	5.1	6.3	85.2	○
	7	7.5	5.0	1.2	-	-	-	-	-	0.0015																	-	149	99	24.0	31.3	113.4	○
8											7.5	5.0	1.5	2.5	-	-	-	0.0057	-	0.90	225	129	6.1	6.1	110.2	○
	9	7.5	5.0	1.2	2.5	-	-	0.05	0.0052	-																	0.90	199	112	3.2	9.9	108.6	○
10											7.5	5.0	1.5	-	2.0	-	-	-	0.0020	0.10	193	113	16.6	29.0	77.0	○
	11	7.5	5.0	1.5	-	-	-	0.15	-	0.0015																	0.10	172	104	17.4	23.3	62.3	○
12											7.5	5.0	1.8	2.5	-	-	0.15	-	0.0015	0.90	184	108	11.2	10.5	147.9	○
	13	7.5	10.0	1.8	2.5	-	-	0.15	0.0120	0.0015																	0.90	230	158	15.8	24.6	160.5	○
14											7.5	12.5	1.5	-	1.0	1.5	-	0.0140	-	0.10	212	111	3.5	3.9	55.9	○
	15	7.5	5.0	1.5	2.0	1.0	1.5	0.08	0.0060	0.0015																	0.90	236	131	3.3	3.7	5.05	○
101											7.5	5.0	-	2.5	-	-	-	-	-	0.90	83	37	0.5	2.2	0.2	×
	102	8.0	5.5	0.2	-	-	-	-	-	-																	0.10	95	62	2.6	2.0	0.3	×
103											7.5	5.0	1.5	2.5	1.5	1.5	-	-	-	0.90	245	135	1.8	1.6	26.0	△
	104	5.0	5.0	1.8	-	-	-	-	-	-																	0.10	54	26	11.9	10.1	0.5	○
105											10.0	5.0	1.8	-	-	-	-	-	-	0.10	169	-	0	0	2.1	○
	106	8.0	5.0	1.5	-	-	-	0.15	-	-																	0.10	157	90	12.0	13.6	88.7	×
107											8.0	5.0	1.8	-	-	-	-	-	0.0045	0.10	207	115	6.0	6.9	93.7	×
	108	7.5	5.0	1.2	7.0	-	-	-	-	0.0015																	-	247	210	1.8	1.1	24.0	△
109											7.5	5.0	1.5	2.5	-	-	0.15	-	0.0015	5.50	166	101	3.1	4.4	8.4	○

Sample No.1-15 is a sample of the present invention in table 1, and sample No.101-109 is a duplicate.By the way, Fe handles as impurity element in alloy of the present invention, and when smelting the preparation alloy, Fe can enter alloy from raw material, if its amount increases can have a negative impact to intensity.So table 1 shows Fe content.

On the weldability hurdle of table 1, circle symbolic representation " flawless ", triangle is represented " a small amount of crackle ", cross symbols is represented " a large amount of crackle ".

The result of table 1 demonstrates, and when the high-temperature behavior with sample, when creep rupture strength at high temperatures and weldability were estimated jointly, the embodiment of the invention was better than comparative example.

No.106 and No.107 have satisfied creep-rupture strength in comparative example, but weldability is low.Though No.104 and No.105 have good weldability, the hot strength of No.104 (tensile strength and yielding stress) and creep-rupture strength are low, and high temperature unit elongation and the creep-rupture strength of No.105 are poor.No.105 does not have 0.2% yield value of stress, because test specimen ruptures immediately when test, therefore should value not measure.No.109 presents low creep-rupture strength, because its Fe content height.

With the test specimen No.1 polishing of the embodiment of the invention, with the corrosion of Marble reagent.When electron microscope (amplifying: 5000 times) is observed down, find that metal structure comprises 88% (volume) intermetallic compound Ni ₃Al.

The test specimen that Fig. 1 and 2 illustrates embodiment of the invention No.12 and comparative example No.102 carries out the photo of weldability and dye check test.Coloured portions among Fig. 2 is represented the crackle that occurs.

Ni of the present invention ₃The Al based heat resistant alloy is suitable as the heat-generating pipe that for example uses in the steel process furnace, the cracking tube that uses in the pyrolysis oven in furnace bottom roll that uses in process furnace and petrochemical industry field.Generally prepare alloy and these products are produced in alloy casting by smelting technology.Certainly these products are suitable for casting, but will carry out solution heat treatment about 1100-1200 ℃ temperature when needing.It is more even that this processing is organized product, and further improve performance.

Alloy of the present invention is suitable for as the powder type that forms the coating material that clad structure uses.Coating can be undertaken by for example plasma powder welding process (PPW method).

Claims (12)

1, the refractory alloy of a kind of creep rupture strength at high temperatures and excellent weldability, it comprises: Al 6.0-9.0 weight %, Cr 2.0-15.0 weight % and Zr 0.5-3.0 weight %, surplus is Ni and unavoidable impurities, this alloy has by the Ni as its principal phase ₃The metal structure that Al constitutes.

2, according to the refractory alloy of claim 1, it comprise be selected from W greater than 0% to be not more than 5.0 weight %, Mo greater than 0% to be not more than 3.0 weight % and Nb greater than 0% to a kind of element that is not more than 3.0 weight %.

3, according to the refractory alloy of claim 1, it comprise be selected from W greater than 0% to be not more than 5.0 weight %, Mo greater than 0% to being not more than 3.0 weight % and Nb greater than 0% at least two kinds of elements that are not more than 3.0 weight %, its combined amount≤5.0 weight %.

4, according to the refractory alloy of claim 1, it comprise C greater than 0% to being not more than 0.3 weight % and/or N 0.003-0.03 weight %.

5, according to the refractory alloy of claim 2, it contain C greater than 0% to being not more than 0.3 weight % and/or N 0.003-0.03 weight %.

6, according to the refractory alloy of claim 3, it contain C greater than 0% to being not more than 0.3 weight % and/or N 0.003-0.03 weight %.

7, according to the refractory alloy of claim 1, it contain B greater than 0% to being not more than 0.003 weight %.

8, according to the refractory alloy of claim 2, it contain B greater than 0% to being not more than 0.003 weight %.

9, according to the refractory alloy of claim 3, it contain B greater than 0% to being not more than 0.003 weight %.

10, according to the refractory alloy of claim 4, it contain B greater than 0% to being not more than 0.003 weight %.

11, according to the refractory alloy of claim 5, it contain B greater than 0% to being not more than 0.003 weight %.

12, according to the refractory alloy of claim 6, it contain B greater than 0% to being not more than 0.003 weight %.

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