AU610429B2

AU610429B2 - High damping capacity, two-phase fe-mn-al-c alloy

Info

Publication number: AU610429B2
Application number: AU39815/89A
Authority: AU
Inventors: Chi-Meen Wan
Original assignee: Famcy Steel Corp
Current assignee: Famcy Steel Corp
Priority date: 1988-07-08
Filing date: 1989-07-06
Publication date: 1991-05-16
Anticipated expiration: 2009-07-06
Also published as: AU3981589A; WO1990000629A1; EP0380630A1; DE68919672T2; JPH03500305A; EP0380630A4; EP0380630B1; ATE114736T1; DE68919672D1; CA1336364C

Abstract

Carbon steels and other hot-and cold-workable ferrous alloys generally have poor damping capacity as compared to that cast iron (gray cast iron, malleable cast iron and ductile cast iron). This is because the graphite in cast irons helps to absorb the damping force and depresses the damping wave. But cast iron can not be rolled into strip of sheet. By controlling the correlated concentrations of manganese, aluminum and carbon, Fe-Mn-Al-C based alloys are made to be alpha + gamma two-phase alloy steel with different alpha and gamma volume fractions. With particular ferrite volumes, workable Fe-Mn-Al-C based alloys have equivalent and better damping capacity than that of cast irons especially in the high frequency side. Such alloys suppress the vibration noise that comes from machine rooms, motors, air conditioners, and etc. Chromium and other minor amount of elements can be added to this alloy system to improve the corrosion resistance.

Description

i1.4 1u |.6 zAXMAnjsibdou llI!61e q6q p: ZAXMAnisdOdwl0)N rlH0d9DV'i Ot 1. Ill IIIS III 11 6 8 1'1 ll PI DATE 05/02/90 APPLN. ID 39815 89 AOJP DATE 22/03/90 PCT NUMBER PCT/US89/02950 INTERNATIONAL APPLICATION PUBLISHED UNDER THE PATENT COOPERATION TREATY (PCT) (51) International Patent Classification 4 (11) International Publication Number: WO 90/00629 C22C 38/04, 38/06, 38/38 Al (43) International Publication Date: 25 January 1990 (25.01.90) (21) International Application Number: PCT/US89/02950 (81) Designated States: AT (European patent), AU, BE (European patent), CH (European patent), DE (European pa- (22) International Filing Date: 6 July 1989 (06.07.89) tent), FR (European patent), GB (European patent), IT (European patent), JP, KR, LU (European patent), NL (European patent), SE (European patent).

Priority data: 218,695 8 July 1988 (08.07.88) US Ia__A_:I 1Qo'( nAoLoA.R_ US Published SECTION a) DIRECTION SEE FUOl.1 (71) NAME DIRECTED PAMc. TE.t_ copo ,op Drive, Hacienda Heights, CA 91745 (US).

(74) Agert: MacQUEEN, Ewan, 886 Piermont Ave., Pier- mont, NY 10968 y TMh's document contains the ic.:ts made under 49 and is correct for Spri-.ting.

(54)Title: HIGH DAMPING CAPACITY, TWO-PHASE FE-MN-AL-C ALLOY (57) Abstract Carbon steels and other hot-and cold-workable ferrous alloys generally have poor damping capacity as compared to that cast iron (gray cast iron, malleable cast iron and ductile cast iron). This is because the graphite in cast irons helps to absorb the damping force and depresses the damping wave. But cast iron can not be rolled into strip of sheet. By controlling the correlated concentrations of manganese, aluminum and carbon, Fe-Mn-Al-C based alloys are made to be a y two-phase alloy steel with different a and y volume fractions. With particular ferrite volumes, workable Fe-Mn-Al-C based alloys have equivalent and better damping capacity than that of cast iions especially in the high frequency side. Such alloys suppress the vibration noise that comes from machine rooms, motors, air conditioners, and etc. Chromium and other minor amount of elements can be added to this alloy system to improve the corrosion resistance.

inventor(), UPPU'.ILUI £IL~u j u L r" Aienallon or Imalation day o 0 resuir. Declared at New York this 16th day of January To: Famcy Steel Corpration The Commissioner of Patents, COMMONWEALTH OF AUSTRALIA (Si naturc o LciTurah) ARTHUR S. CAVE CO.

PATENT AND TRADE MARK ATTORNEYS

SYDNEY

S.C.-4 AMD/0347a i1- Two-Phase High Damping Capacity Fe-Mn-Al-C Based Alloy Background For the past years o:+y two-phase alloy have been developed by adding molybdenum and cobalt to the Fe-Ni-Cr alloy system for the purpose of making alloys having both better stress corrosion and hydrogen embrittlement resistance. But none of these alloys was designed for the purpose of higher damping capacity. The iron based materials that have been using for high damping capacity are cast irons. The graphite in those cast iron is the most important factor for the absorbing of the high frequency vibration wave. But cast irons S generally are not workable. Therefore the usage of cast irons Oo in high damping applications is limited.

Description of the Drawings In the drawing Figure 1 depicts the damping capacity curve of an alloy of the invention; and "Figure 2 depicts the damping capacity curve for ductile iron.

Detailed Description In the Fe-Mn-Al-C based alloys, manganese and carbon are Y phase formers and aluminium is c phase former. By suitable chemical composition arrangement Fe-Mn-Al-C based alloys can be designed to be full y phase steel such as Fe-29Mn-7Al-1C. Reduction of the manganese or carbon or both of them and the increase of aluminium can promote the V IU/Uq a la appearance of a phase, and make the alloy an a+y two-phase steel. The volume fraction of a phase can be easily controlled by changing the amount of manganese or/and carbon or/and aluminium or/and some other ferrite former elements.

Alloys according to the invention contain, in weight percent, 10% to 45% manganese, 4% to 12% aluminium, up to 12% chromium, 0.01% to 0.7% carbon and the balance being iron apart from incidental impurities, and are characterised by a microstructure containing about 25 to about 75 volume percent ferrite, with the remainder austenite and by a high damping capacity on the order of that of a cast iron. Some other minor elements such as nickel, molybdenum, columbium, cobalt, silicon, copper, boron, vanadium, tungsten, zirconium, titanium, nitrogen, niobium, etc. may be further comprised in this alloy.

*OS

i 5 i 0 S 0 L WO 90/00629 PCT/US89/02950 -2- Example 1.

This example illustrates the effect of the element compositions on the change of a volume fraction in the Fe-Mn-AI-C based alloys. Manganese and carbon are austenite phase stabilizers and aluminum is a ferrite phase former. The effect of the carbon content on the ferrite fraction of the Fe-Mn-Al-C based alloys is shown in Table I. in which the chemical composition of aluminum and manganese are essentially constant and the carbon content decreases from 0.5 wt% to 0.11 wt%.

With the decreasing of carbon content, the ferrite phase volume fractions of the alloys increases from 0% to 36%. With the change of manganese, carbon and aluminum contents, the volume fractions of ferrite phase and balanced y phase is controlled to be from 25% to 75%. Within this ferrite fraction range, excellent damping capacity is always found in the Fe-Mn-Al-C based alloy.

Table I comoosition Mn I Al C ferrite vol% alloy (wt%) 1 26.0 7.4 0.5 0 2 26.3 7.6 0.34 11.9 3 25.8 7.4 0.11 36.0 Example 2.

This example illustrates the good damping capacity of the said cay two-phase Fe-Mn-Al-C based alloys which have been measured and determined with comparison to ductile cast iron. The test sample of the invention contained 19.7M.n-5.84Al-5.74Cr-0.19C. The ferrite volume fraction is about 65% balanced with y phase. The dampir.g capacity curves of the damping capacity tests of the Fe-Mn-Al-C based alloy and ductile cast iron are shown in Fig. 1 and Fig. 2. It is seen that the damping capacities of the two alloys are almost equivalent.

WO 90/00629 PC/US89/02950 -3- Example 3.

This example illustrates the good workability of a+y two-phase Fe-Mn-Al-C based alloys. The alloys listed in Table II were cast into ingot; homogenized at 1200°C; cut and hot forged at 12000C; further annealed at 11500C and descaled. The alloys were cold rolled into 2.0 mm thick strip and annealed. The ferrite volume percentages of these strips were measured and are listed in Table III. The mechanical properties of these annealed strips are also listed in Table III. It is seen that the alloys of the invention have good workablility and excellent mechanical properties.

Table 11.

alloy no. Mn Al C Cr Other #109 25.1 6.7 0.287 5.6 200ppmN 2 #108 30.3 6.3 0.244 5.8 #320 21.6 6.8 0.11 0 #317 20.0 6.1 0.4 5.5 0.92Mo #129 33.4 10.3 0.47 2.1 0.2Ti #116 29.5 10.2 0.4 0 0.1Nb Table Ill sample no. 0.20% proof ultimate tensile elongation hardness ferrite stress(ksi) stress (ksi) (Rb) #109 45 103 42 84 #108 39 94 44 80 28 #320 41 98 43 82 67 #317 44 101 41 83 #129 61 112 38 86 #116 59 109 37 85 73 c'

Claims

1. A ferrite-austenite two-phase alloy of high damping capacity having a composition comprising 10 to 45 wt% manganese, 4 to 15 wt% aluminium, up to 12 wt% chromium, 0.01 to 0.7 wt% carbon and the balance being iron apart from incidental impurities, with the ferrite phase of said alloy having 25% to 75% by volume of the phase present, the remainder being essentially austenite, said alloy having a damping capacity of a substantially similar level as that of ductile iron. S. 0 S. S 0 *t S S *5 0@ S S. a 5 5 *5 The The The The The The The The The The The The alloy of alloy of alloy of alloy of alloy of alloy of alloy of alloy of alloy of alloy of alloy of alloy of claim claim claim claim claim claim claim claim claim claim claim containing containing containing containing containing containing containing containing containing containing containing 0 to 4.0 wt% molybdenum. 0 to 4.0 wt% copper. 0 to 2.0 wt% nickel. 0 to 3.5 wt% niobium. up to 500 ppm boron. up to 0.2 wt% nitrogen. 0 to 3.5 wt% titanium. 0 to 2.0 wt% cobalt. 0 to 3.5 wt% vanadium. 0 to 3.5 wt% tungsten. 0 to 2.0 wt% zirconium. 0 to 2.5 wt% silicon. claim 1 containing

14. A ferrite-austenite two-phase alloy, substantially as herein described with reference to the accompanying drawings. DATED this 22nd day of February, 1991. FAMCY STEEL CORPORATION By Its Patent Attorneys ARTHUR S. CAVE CO.