CN1004814B - Modified gh36 alloy contg. al and/or mg - Google Patents

Abstract

The present invention relates to a modified GH36(ei481) alloy with good performance, which is obtained by adding proper amount of Al, Mg or Al and Mg to GH36(ei481) separately. The modified GH36(ei481) alloy has no lasting notch sensitivity, and the comprehensive performance is improved. By adjusting the content of Al and Mg properly, sigma0.2 approaches to 80 KG/mm+2, and smooth stress rupture life and notch stress rupture life are enhanced nearly one more order of magnitude than that of GH36(ei481).

Description

A kind of aluminium that contains. the GH36 of magnesium (3H481) modified alloy

The invention belongs to high temperature alloy.

The aero-engine turbine disk that uses about 650 ℃ and other high-temperature components are (as heavy ring, fastening piece), GH36 alloy with material one China (is seen " superalloy handbook, nineteen eighty-two version) be to see Г О С Т 5632 with reference to Soviet Union Э И 481(, 1976 or C. Б .M а с л e н к о в, " ж а р о п р о ч н ы e С m а л и к С п л а в ы, С П Р А В О Ч Н И К ", MOCKBA, " М Е Т А Л y Р Г И Я ", 1983, cmp, 80～82) develop.It is the sedimentation type austenitic alloy of main strengthening phase that GH36 and Э И 481 all belong to carbide.Except that GH36 has the certain limitation (N), other compositions and performance and Э И 481 are basic identical or close.The chemical ingredients of GH36 (%) is: 0.36～0.40C, 0.30～0.8Si, 7.5～9.5Mn, 11.5～13.5Cr, 7～9Ni, 1.1～1.4Mo, 0.25～0.50Nb, 1.12～1.55V,＜0.12Ti,＜0.03S,＜0.035P,＜0.1N, all the other Fe.

In recent years, though many domestic colleagues make moderate progress alloy room temperature yield strength σ 0.2 and enduring quality by the production technique (as forging, smelting etc.) of improving GH36, very undesirable.Especially it is pointed out that the GH36 of present use different with the equal degree of Э И 481 alloys exist persistent notch sensitivity, i.e. breach τ creep rupture life _и＜smooth creep rupture life τ.That is τ H/ τ=λ＜1(λ is called lasting sensitivity factor of notch).For example, 650 ℃ of the turbine disks, 38kg/mm ²Following smooth creep rupture life is between 60 to 160 hours, and only 20～30 hours creep rupture life of average breach.

The existing of persistent notch sensitivity (λ＜1) obviously is to influence GH36 and Э И 481 in one of the major reason in high temperature stressing conditions following work-ing life, so eliminate GH36 and Э И 481 persistent notch sensitivities just become the important topic that improves its work-ing life.

The contriver finds the GH36 sample analysis with persistent notch sensitivity, and their nitrogen content is general all about 0.0700% or higher.Find that by metallographic and scanning electron microscopic observation along with sample (N) increases, the size of the non-metallic inclusion of nitrogen vanadium carbide (niobium) type is changed from small to big, being distributed by disperse becomes a chain distribution, and the part particle has water caltrop.Meanwhile, obviously reduced effectively, risen the VC of dispersion-strengthened action because the part vanadium enters MC type nitrogen vanadium carbide (niobium).This shows that the GH36 alloy contains higher (N) (although＜0.1%), is to cause its lasting unit elongation δ to descend, and crackle is easy to take place and development.Thereby the major reason that persistent notch sensitivity occurs.Yet because furnace charge generally all adopts a certain proportion of returns, used ferrochrome nitrogen content is higher and contain the high austenitic alloy electrosmelting process of manganese and be accompanied by reasons such as serious suction nitrogen in actual production, and the GH36 nitrogen content is general all about 0.0700%.

For eliminating harmful effect than high nitrogen content, eliminate GH36 alloy persistent notch sensitivity simultaneously, and other mechanical properties are satisfied or significantly be better than the technical qualification specified requirement, the inventor has adopted following approach and has obtained satisfied result.

One, in the GH36 alloy, adds 0.10～0.60%Al.

The contriver is keeping under other compositions condition basic identical or close with hydrogen, oxygen level and GH36 with the logical Ar remelting GH36 returns of 10kg vacuum induction furnace, produce respectively contain Al*≤0.001%(be set at be similar to no Al); 0.09%, 0.23%, five kinds of spindles such as 0.33% and 0.58%, and under same forging process, be swaged into Φ 20mm coupon with the 400kg air hammer, through 1140 ℃ * 80 '/the heat up standard thermal treatment of 780 ℃ * 16h/ air cooling of water-cooled+670 ℃ * 14h, the sampling of every subsequently stove is some, measures δ, ψ under room temperature unit elongation δ, reduction of area ψ, yield strength σ 0.2, breaking tenacity σ b and 650 ℃, σ 0.2, σ b and 650 ℃, 38kg/mm respectively ²Under δ, ψ, smooth creep rupture life τ and breach τ creep rupture life H, and average, the gained result as Figure 1-3.Fig. 1 is that Al is to tested alloys room temperature tensile Effect on Performance; Fig. 2 is that Al is to 650 ℃ of following stretching Effect on Performance of tested alloys; Fig. 3 shows the influence of Al to enduring quality under 650 ℃ of tested alloys, the 38kg/mm2.By Fig. 1-3 as can be seen:

1. in the GH36 alloy, add about 0.10～0.60%Al, can eliminate persistent notch sensitivity fully, and stretch and the enduring quality requirement that all can meet the specification;

2. when Al content was 0.20～0.40%, the GH36 alloy of remodeling had optimum properties, and room temperature σ 0.2 can improve 5～10kg/mm than no AlGH36 maximum ²σ 0.2 maximum under 650 ℃ can improve 5%, and the τ maximum can reach 347 hours, and τ H was greater than 640 hours, and is higher 1～2 times than no AlGH36 respectively;

3.Al measure when too high, over-all properties is not good.

Two, in the GH36 alloy, add Mg.

The contriver is with 20kg non-vacuum induction furnace remelting GH36 returns, with the deoxidation of Si-Ca powder.Add Ni-Mg before the tapping and produce respectively that to contain Mg be that 0.0004%(is set at approximate first Mg); 0.0016%; 0.0047%; 0.0070%; Five stove tested alloys such as 0.0092% grade, other compositions and hydrogen, oxygen level and GH36 are basic identical or close, forging process, thermal treatment process and data processing with scheme one, gained result shown in Fig. 4-5.Fig. 4 is that Mg is to tested alloys room temperature tensile Effect on Performance; Fig. 5 is that Mg is to 650 ℃ of tested alloys, 38kg/mm ²The influence of following enduring quality.By Fig. 4～5 as can be seen: when Mg content was 0.0040～0.0080%, the GH36 alloy room temperature tensile performance of remodeling did not have noticeable change, but had best enduring quality, and promptly persistent notch sensitivity is eliminated fully.When Mg content was 0.0070%, creep rupture life was the highest.Mg too high levels (is 0.0092% as test conditions), creep rupture life with do not add the Mg alloy type seemingly, and produce notch sensitivity.

Three, in the GH36 alloy, add Al, Mg, but adopt refining of induction furnace list and induction furnace to smelt the different process that adds the electroslag remelting.

The contriver has been smelt the ingot that contains different al, Mg with the induction furnace smelting process with returns, it is swaged into electrode through esr.During esr, Al, Mg content by in control slag ingredient, working chamber's atmosphere and the consumable electrode are controlled at required scope with the Al in the resmelting ingot, Mg, produce respectively to contain 0.04%Al, and＜0.0005%Mg(sets approximate no Al, Mg); 0.24%Al, 0.0028%Mg; 36%Al, 0.0033%Mg; 0.31%Al, 0.0038Mg%; 0.44%Al, 0.0040%Mg; 0.29%Al, 0.0061%Mg; Deng 6 stove alloys.Identical with scheme 1 in forging process with thermal treatment process, take a sample some respectively to each stove tested alloys under other compositions except that Al, Mg and the hydrogen-oxygen content situation basic identical or close with GH36, measure its room temperature tensile performance δ, ψ and σ 0.2, same stove data get that it is average, the gained result as among Fig. 6 ▲-shown in; Measure it at 650 ℃, 38kg/mm ²Under enduring quality, the gained result is as shown in Figure 7.The first half among Fig. 7, τ H be with △-expression, τ with ▲-expression, Lower Half δ with ▲-expression.

Be the influence of more different melting method to GH36 modified alloy mechanical property, the contriver has smelted six stoves with non-vacuum induction furnace and has contained the GH36 modified alloy that Al is 0.11～0.20% different Mg content.Measure its room temperature tensile performance δ, ψ and σ 0.2 and 650 ℃, 38kg/mm ²Following enduring quality δ, τ H and τ, the gained result is illustrated among Fig. 6 and Fig. 7 with 0---and 0---respectively.Among Fig. 6 and Fig. 7 with-expression room temperature tensile performance δ, ψ and σ 0.2 and 650 ℃, 38kg/mm ²Under enduring quality δ, τ H and τ take from Fig. 4 and result shown in Figure 5 respectively.

By Fig. 6 and Fig. 7 as can be seen:

1. when adopting induction furnace list smelting method, Al content is in 0.11～0.20% scope, and best Mg content is 0.0040～0.0000%;

2. when adopting induction furnace smelting+esr duplex technology, Al content is in 0.24～0.44% scope, and best Mg content is 0.0020～0.0040%.As being 0.36% as Al, Mg is 0.0033% o'clock, and τ=807 hour are τ H=2535 hour, than not adding Al, the GH36(Э И 481 of Mg) improve nearly order of magnitude.And lasting unit elongation δ can reach 9.2%, and ψ can reach 25.8%, and room temperature δ＞20%, ψ are near 40%, and σ 0.2 is near 80kg/mm ²

Add Al or Mg or Al, Mg among the GH36, so that its performance significantly improves is because Al, Mg have improved the shape and the distribution of inclusion.

More than all finger compositions or content be all weight %.

Claims (5)

1, modified alloy a kind of GH36(Э И 481) is characterized in that its Chemical Composition (weight %) is: 0.36～0.40C, 0.30～0.80Si, 7.5～9.5Mn, 11.5～13.5Cr, 7～9Ni, 1.1～1.4Mo, 0.25～0.50Nb, 1.12～1.55V,＜0.12Ti,＜0.03S,＜0.035P,＜0.1N, 0.10～0.60Al, all the other Fe.

2, alloy as claimed in claim 1 is characterized in that the optimum Al weight percentage is 0.20～0.40.

3, alloy as claimed in claim 1, when it is characterized in that adopting single smelting method, can add best Mg weight percentage is 0.0040～0.0080.

4, alloy as claimed in claim 1, when it is characterized in that adopting esr duplex technology, can add best Mg weight percentage is 0.0020～0.0040.

5, alloy as claimed in claim 1 is characterized in that said Al can be replaced by Mg, and its optimum content (weight %) is 0.0040～0.0080%.

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