CN1414130A

CN1414130A - Fe-Cr-Ni cast alloy haring both creep deformation and toughness and its manufacturing method

Info

Publication number: CN1414130A
Application number: CN 02131317
Authority: CN
Inventors: 王根启; 阙志建; 张小筠; 甄宝林
Original assignee: MANUR (YANTAI) INDUSTRIAL Co Ltd
Current assignee: MANUR (YANTAI) INDUSTRIAL Co Ltd
Priority date: 2002-09-27
Filing date: 2002-09-27
Publication date: 2003-04-30
Anticipated expiration: 2022-09-27
Also published as: CN1177074C

Abstract

A Fe-Cr-Ni based cast alloy with better high-temp creep and toughness contains C (0.03-0.2 Wt.%), Si (0.1-1.0), Mn (0.2-1.2), Cr (20-23), Ni (30-35), Nb (0.8-1.2), Zr (0.02-0.3), Ti (0.03-0.3), and RE (0.01-0.2).

Description

A kind of high temperature creep and flexible Fe-Cr-Ni base casting alloy and manufacture method thereof taken into account

1, technical field

The invention belongs to Fe-Cr-Ni base alloy field, specifically a kind of high temperature creep and flexible Fe-Cr-Ni base casting alloy composition and manufacture method thereof taken into account.

2, background technology

China has successively introduced 33 cover large chemical fertilizer production units so far from the seventies.Wherein there are 13 covering devices to use high-temperature alloy furnace tube.China has begun the research of boiler tube production domesticization since then, can produce the boiler tube that meets the demands up till now.But the key part on the supporting with it following collecting tubule: it is rich that the Incoloy800H in following collecting tubule (I) and the following collecting tubule (II) still fails to break away from being stranded of manufactured materials and technology, long-term dependence on import, and the cycle is long, the pipe material generally also takes 3～4 months, but also will further process, can not satisfy the requirement of manufacturing cycle at all.The domestic imitation quality can not guarantee.In addition, above-mentioned parts are generally operational between 800～900 ℃, and interior media is hydrogen, suffer heavy losses undoubtedly in case reveal, even there is problem to stop once in a while for a short time, and at least 150 ten thousand yuan of the losses of every day, therefore very strict for the requirement of these parts.

Incoloy800H is U.S.'s trade mark, its manufacturing process " melting → ingot casting → surface treatment → heating → shaping → cogging → perforation → heating → rolling → heating → ... rolling → thermal treatment " more numerous and diverse.

Because the production domesticization of hydrogen manufacturing conversion furnace device, this partial design is still continued to use original design, and this part material of China first～3rd equipment all is imports.This later some domestic imitation of part material, but ubiquity complex process, the production cycle is long, the manufacturing cost height, and the limited defective of specification, having only rolling pipeline section is spliced the length that just can reach design, overall technology and product can not satisfy the requirement in market far away.

3, summary of the invention

The purpose of this invention is to provide a kind of high temperature creep and flexible Fe-Cr-Ni base casting alloy and manufacture method thereof taken into account, overcome the defective of above-mentioned existing procucts and manufacture method, produce the Fe-Cr-Ni base casting alloy that meets the demands.Product after the improvement has all demonstrated fully the over-all properties of alloy from Chemical Composition and manufacturing process.

Purpose of the present invention can reach by following measure: a kind of high temperature creep and flexible Fe-Cr-Ni base casting alloy taken into account, and its component (weight percent) is: C 0.03-0.2%; Si 0.1-1.0%; Mn 0.2-1.2%; Cr 20-23%; Ni 30-35%; Nb 0.8-1.2%; Zr 0.02-0.3%; Ti0.03-0.3%; RE 0.01-0.2%, RE are one or more among La, Y or the Ce; Surplus is Fe and unavoidable impurities.

Preferred ingredients (weight percent) is: C 0.08-0.1 8%; Si 0.5-1.0%; Mn0.8-1.2%; Cr 20 23%; Ni 30-33%; Nb 0.8-1.2%; Zr 0.03-0.1%; Ti0.05-0.15%; RE 0.01-0.05%, RE are one or more among La, Y or the Ce; Surplus is Fe and unavoidable impurities.

Can satisfy basic demand 900 ℃ of work at Incoloy800H, and finish under the rolling technology condition, thereby this alloy having borrowed outside its basic alloy element Cr, Ni at mirror, is a kind of new alloy ingredient and manufacturing process fully.

At first the content of determining C is at 0.03-0.20%, and preferable range is 0.08-0.18%, is because guaranteed that alloy has best creep rupture strength.Content is crossed and low can be caused strength property to descend and the unit elongation of alloy surpasses range of needs.

Si content is determined at 0.1-1.0%, has both guaranteed that the antioxidant property of alloy is improved, and has considered again and the ratio of C that the welding property that helps alloy is improved, and through experiment repeatedly, finds that Si content effect when 0.5-1.0% is preferable.

Mn content determines that at 0.2-1.2% preferable range is 0.80-1.20%, except the requirement of satisfy smelting deoxidation, also considers the ratio with Si content, has effectively improved the weldability of alloy.

Nb determines that at 0.8-1.20% except that the requirement of having satisfied the material anti intercrystalline corrosion, main is to form certain carbide quantity, and at high temperature very stable, has obviously improved alloy creep-resistant property at high temperature.

Ti is very similar in alloy to the performance of Nb, but the Ti element is very active, should not add too much, otherwise can form the oxide inclusion of some amount, and destroy the over-all properties of alloy.On the other hand, exist in the time of Nb and Ti, form complexity more, stable, tiny carbide plays than the more effective effect of the two any independent adding, and this effect is beyond thought.When above-mentioned Nb content is arranged, the content of Ti is feasible in the 0.03-0.30% scope, be lower than 0.03% o'clock DeGrain, be higher than at 0.30% o'clock then when adopting antivacuum smelting, form more oxide inclusion and have influence on the over-all properties of alloy, if though adopt vacuum metling can add more amount, superfluous metal no longer obviously increases its effect, cause waste, also bring difficulty and might reduce alloy property to manufacturing process.Through repetition test, the best results when content of Ti is kept 0.05-0.15%,

The adding of Zr helps the interpolation of Ti; it can sacrifice oneself; protection Ti not by or few oxidized; also form more tiny simultaneously with Nb, Ti and carbon; (Nb, Ti, Zr) C of distributing of complexity and disperse more; more help improving the high-temperature creep resistance of alloy, particularly increased the stability under the high temperature, help prolonging the work-ing life of alloy.The content range of selected Zr is at 0.02-0.30%, particularly between 0.03-0.10% no matter from the performance that improves alloy and improve smelt, the pouring technology condition all is ideal.

Thulium RE, no matter Ce, Y and La can play in alloy smelting the strong desoxydatoin except equal, also help inclusion balling, improve the oxidation resistant ability of alloy, its content can meet the demands when 0.01-0.20%, if content is too high, can cause a crystal boundary and an intergranular crack to produce micro-flaw.So these elements are unsuitable too high.Find that through experiment effect is best in the 0.01-0.05% scope.

And a large amount of matrix element Cr, Ni, Fe element are the fundamental elements that forms the anti-oxidant and high temperature creep property of alloy, and guarantee that alloy can form austenite structure, and this is the fundamental prerequisite that can guarantee use alloy high-temp under.

And non-alloying elements such as other residual element P, S unavoidably are brought into, and should control to alap degree.In alloy of the present invention, the content of P generally is controlled at below 0.02%, and the content of S generally is controlled at below 0.015%.

Purpose of the present invention can also reach by following measure: it forms through following operation manufacturing: use under melting → centrifugal casting → mechanical workout or the as cast condition.Melting can be adopted medium-frequency induction furnace or other electric furnace, AOD stove, VOD etc.; Casting is adopted horizontal or the vertical centrifugal cast, also can adopt precision casting, lost foam casting, sand mold casting etc.

From Chemical Composition, at first the carbon content of product innovation has improved, make this corresponding increase based on carbide reinforced high temperature creep property, and by adding Nb, Ti, Zr and rare earth (RE) and controlling its content, can guarantee to form complicated (Nb, Ti, Zr) C and be tiny, the carbide that disperse distributes, highly stable in ag(e)ing process.This just for this kind material at high temperature life-time service lay a good foundation.Also have only later centrifugal casting technique the material property of this composition can be optimized.

Because centrifugal casting technique is with the slow-moving solid moulding of liquid metal under dynamically.The mould of high speed rotating can provide the universal gravity constant bigger 100 times than other forging type ingot casting, useful composition metal is thrown to the metal pattern of outer wall at a high speed, and the inclusion of metal and gas are discharged to the product inside pipe wall, all remove in the mechanical processing technique afterwards.That is the use portion of tissue densification of product, inclusion and gas are seldom.

The design of this kind composition and manufacturing process have determined the raising of product high temperature creep property and taken into account the toughness of material, and at high temperature life-time service have good stability.The product of Zhi Zaoing itself is exactly a pipe simultaneously, thus need not to be rolled all that done for perforation are prepared and repeat-rolling to the required thermal treatment repeatedly of specified dimension, so technological process also just obviously has been simplified.This product can be as cast condition or mechanical workout attitude according to the inside and outside wall of working conditions, and the footpath is just passable simply and the specification of product is as long as select suitable mould.And the process of a pipe of centrifugal casting has only several minutes, therefore from making required number of devices and scale, operation, processing whole process, lumber recovery, determines the key reason that cost descends beyond doubt.

The manufacturing cycle of product shortens to original 1/10th after improving; Cost is original 1/5th; Creep rupture strength improves more than 30%; Tough sexual satisfaction service requirements.

The creep-rupture strength of material of the present invention and INCOLOY800H (MPa) contrast sees Table 1.Table 1, novel material and the comparison of 100,000 hours creep-rupture strengths (MPa) of INCOLOY800H

Thermal stress	??????650℃		????????700℃		?????????800℃		????????900℃
	??????650℃		????????700℃		?????????800℃		????????900℃		Mean value	Minimum value	Mean value	Minimum value	Mean value	Minimum value	Mean value	Minimum value
	Incoloy 800H	??80	??64	????42	??33.5	????24	????19	????10.5	Mean value	Minimum value	Mean value	Minimum value	Mean value	Minimum value	Mean value	Minimum value	??8
Novel material	Incoloy 800H	??80	??64	????42	??33.5	????24	????19	????10.5	??103	??84.6	????75	??61.1	????39.2	????32	????20.5	??16.7	??8

4, embodiment

Embodiment 1

The raw material ratio that is used to make this alloy is (KG/100KG material)

Ni plate: 32.5

FeCr(65％)?：30.5

Pure iron: 33.2

FeNb(60％)?：2

FeMn(80％)?：1.15

FeSi(75％)?：0.35

FeSiRE41??：0.2

FeSiZr????：0.5

Ti????????：0.1

Consider scaling loss, each component addition is a little more than 100% (down together) during batching.

With the raw material of said ratio, place the 250Kg medium-frequency induction furnace to carry out melting, after 2 hours, liquid steel temperature reaches 1690 ℃ comes out of the stove, and pours into a mould in 1580 ℃, and the type tube rotating speed is 1420rpm during cast, and gravitation multiple G reaches 140.Cast external diameter 165mm, internal diameter 125mm, length 3.35M, heavy 250Kg.

Product is carried out spectrochemical analysis (by the GB11170-89 analytical procedure), normal temperature drawing mechanical performance (testing by GB228-87), high-temperature short delay stretching mechanical property (testing by GB/T4338-1995) and rupture test (testing by GB/T2039-1997)

Test-results is listed in table 2 and the table 3.

Embodiment 2

Press example 1 proportioning raw material: use the 1000Kg intermediate frequency furnace to smelt, cast φ 250/ φ 167 * 3000 uses the 687Kg molten steel after 2 hours, pours into a mould type tube rotating speed 1170rpm, gravitation multiple G=140 in 1530 ℃.

Test-results is listed in table 2 and the table 3.

Embodiment 3

By example 1 batching, use 250Kg stage casing stove to smelt, cast φ 60/ φ 38 * 3500 after 1 hour, molten steel amount 53Kg comes out of the stove in 1700 ℃, 1620 ℃ of cast, the type tube rotating speed is 2500rpm, gravitation multiple G=140.

Test-results is listed in table 2 and the table 3.

Embodiment 4-8

By example 1 batching, at different product specifications, molten steel amount, temperature, rotating speed are adjusted accordingly, and test-results is listed in table 2 and the table 3.

The alloy compositions of table 2, embodiment 1-8

Sequence number		?Si	?Mn	?P	??S	??Cr	??Ni	??Nb	??Zr	??Ti	??Ce
Sequence number		?Si	?Mn	?P	??S	??Cr	??Ni	??Nb	??Zr	??Ti	??Ce	??1	??0.108	?0.602	?0.815	?0.13	??0.0102	??20.18	??33.15	??1.1	??0.041	??0.07	??0.016
??2	??0.125	?0.604	?0.768	?0.0132	??0.0139	??19.97	??33.3	??1.07	??0.037	??0.062	??0.0203	??1	??0.108	?0.602	?0.815	?0.13	??0.0102	??20.18	??33.15	??1.1	??0.041	??0.07	??0.016
??2	??0.125	?0.604	?0.768	?0.0132	??0.0139	??19.97	??33.3	??1.07	??0.037	??0.062	??0.0203	??3	??0.094	?0.71	?0.762	?0.00909	??0.00572	??21.17	??31.2	??1.31	??0.031	??0.051	??0.0132
??4	??0.157	?0.889	?0.96	?0.013	??0.00652	??19.67	??33.94	??0.727	??0.028	??0.035	??0.0083	??3	??0.094	?0.71	?0.762	?0.00909	??0.00572	??21.17	??31.2	??1.31	??0.031	??0.051	??0.0132
??4	??0.157	?0.889	?0.96	?0.013	??0.00652	??19.67	??33.94	??0.727	??0.028	??0.035	??0.0083	??5	??0.137	?0.851	?1.04	?0.0117	??0.0045	??20.36	??34.88	??0.746	??0.234	??0.0421	??0.0182
??6	??0.159	?0.564	?0.859	?0.0145	??0.00429	??20.26	??34.19	??0.652	??0.0196	??0.0387	??0.0231	??5	??0.137	?0.851	?1.04	?0.0117	??0.0045	??20.36	??34.88	??0.746	??0.234	??0.0421	??0.0182
??6	??0.159	?0.564	?0.859	?0.0145	??0.00429	??20.26	??34.19	??0.652	??0.0196	??0.0387	??0.0231	??7	??0.126	?1.03	?0.827	?0.0149	??0.00888	??21.32	??32.45	??1.24	??0.0345	??0.161	??0.0547
??8	??0.15	?0.597	?0.952	?0.0182	??0.0046	??19.96	??32.55	??1.13	??0.0263	??0.076	??0.0226	??7	??0.126	?1.03	?0.827	?0.0149	??0.00888	??21.32	??32.45	??1.24	??0.0345	??0.161	??0.0547

Annotate: the sequence number in the table is corresponding with the embodiment sequence number.

The experimental performance result of table 3, embodiment 1～8.

	Normal temperature stretches			High temperature, short time				Enduring quality
	Normal temperature stretches			High temperature, short time				Enduring quality			Sequence number	??σb?MPa	??σs?MPa	??δ％	?Temp.℃	??σb?MPa	???σs?MPa	??δ％	??Temp.℃	?σMPa	??t：hrs
????1	????520	????217	??46	????900	????110	????76	??45	????900	????40	????158	Sequence number	??σb?MPa	??σs?MPa	??δ％	?Temp.℃	??σb?MPa	???σs?MPa	??δ％	??Temp.℃	?σMPa	??t：hrs
????1	????520	????217	??46	????900	????110	????76	??45	????900	????40	????158	????2	????520	????215	??44	????900	????114	????76	??46	????900	????40	????139
????3	????582.6	????340.3	??33.6	????900	????206.2	????118.6	??41.2	????900	????79.5	????10.5	????2	????520	????215	??44	????900	????114	????76	??46	????900	????40	????139
????3	????582.6	????340.3	??33.6	????900	????206.2	????118.6	??41.2	????900	????79.5	????10.5	????4	????591.2	????295.6	??37.6	????900	????157.9	????103.6	??48	????900	????79.5	????9.5
????5	????545	????285	??34	????900	????140	????88	??43	????1000	????40	????81	????4	????591.2	????295.6	??37.6	????900	????157.9	????103.6	??48	????900	????79.5	????9.5
????5	????545	????285	??34	????900	????140	????88	??43	????1000	????40	????81	????6	????557	????292	??39	????900	????150	????103	??48	????1000	????40	????71
????7	????557.5	????293.5	??40	????900	????178	????117	??42	????1000	????40	????71	????6	????557	????292	??39	????900	????150	????103	??48	????1000	????40	????71
????7	????557.5	????293.5	??40	????900	????178	????117	??42	????1000	????40	????71	????8	????580	????374	??40.6	????900	????189	????109	??41	????1000	????40	????67.5

Claims

1, a kind of high temperature creep and flexible Fe-Cr-Ni base casting alloy taken into account, it is characterized in that: its component (weight percent) is: C 0.03-0.2%; Si 0.1-1.0%; Mn 0.2-1.2%; Cr 20-23%; Ni 30-35%; Nb 0.8-1.2%; Zr 0.02-0.3%; Ti 0.03-0.3%; RE 0.01-0.2%, RE are one or more among La, Y or the Ce; Surplus is Fe and unavoidable impurities.

2, casting alloy according to claim 1 is characterized in that: its component (weight percent) is: C 0.08-0.18%; Si 0.5-1.0%; Mn 0.8-1.2%; Cr 20-23%; Ni 30-33%; Nb 0.8-1.2%; Zr 0.03-0.1%; Ti 0.05-0.15%; RE 0.01-0.05%, RE are one or more among La, Y or the Ce; Surplus is Fe and unavoidable impurities.

3, the manufacture method of casting alloy according to claim 1 and 2 is characterized in that: it forms through following operation manufacturing: use under melting → centrifugal casting → mechanical workout or the as cast condition.