Effect of additions of Cr, Mo, W and/or Si on the technological properties of aluminum-iron-nickel bronze

Transcription

1 A R C H I V E S f F O U N D R Y E N G I N E E R I N G Published quarterly as the rgan f the Fundry Cmmissin f the Plish Academy f Sciences ISSN ( ) Vlume 11 Issue 3/ /3 Effect f additins f Cr, M, W and/r Si n the technlgical prperties f aluminum-irn-nickel brnze B. P. Pisarek* Department f Materials Engineering and Prductin Systems, Technical University f Łódź, 1/15 Stefanwskieg Str., Łdź, Pland *Crrespnding authr: address: bguslaw.pisarek@p.ldz.pl Received ; accepted in revised frm Abstract The aim f this study was t investigate the effect f additives f Cr, M, W and / r Si CuAl10Fe5Ni5 brnze, cast int sand mulds, the brnze technlgical prperties such as: prsity, vlumetric shrinkage Sv, linear shrinkage s and prne ht t cracking. The study relate t the newly develped grades aluminum-irn-nickel brnze, with additins f Cr, M, W and/r Si. In rder t determine the technlgical prperties f the test castings were made in the frm f mulding sand, which made the muld cavities designed patterns. T evaluate the prsity and vlumetric shrinkage was used fr digital image analysis methd. Vlumetric shrinkage was determined using develped, the new methd, the surface shrinkage Svp designatin, and then cnverting it t the vlumetric shrinkage, using prepared relatin Sv=f(Djs)*Svp. It was fund that made the brnze ally additins t reduce the size f pres surface area f gas and shrinkage in the test brnze. The prbability f micrprsity with an area f mm 2 can be described by gamma distributin. Changing the chemical cmpsitin f the grades tested brnze strngly alter the first vlumetric shrinkage Sv, and less t change the linear shrinkage s. The increase in gas prsity and shrink in brnze reduces the vlumetric shrinkage and linear. The additin f Cr, M, W and/r Si t the brnze CuAl10Fe5Ni5 des nt change its prne t ht cracking. Keywrds: Innvative Materials And Casting Technlgies, Technlgical Prperties, Aluminum-Nickel-Irn Brnze, Vlumetric Shrinkage, Linear Shrinkage, Prsity 1. Intrductin The aim f this study was t investigate the effect f additive: Cr, M, W and/r Si t the brnze CuAl10Fe5Ni5 n the change: vlumetric shrinkage Sv, linear shrinkage s, prsity and prne t ht cracking. The study arse frm the develpment f new grades aluminum-irn-nickel brnze with additins individually r simultaneusly Cr, M, W and/r Si [1-6]. Knwledge f the characteristic prperties f newly develped technlgical brnze needed fr the prper design: casts and patterns f gating the pwer supply, technlgical prcessing n the liquid ally can btain melting with minimal gassing, r a muld f technlgy. Prsity in castings is due t the presence f gas in the liquid melt and the prcesses assciated with vlumetric shrinkage in a slidifying ally. Saturating gas liquid ally takes place during the prcess: melting, isthermal withstand melt in furnace and puring. With the increase in temperature f the mlten ally increases the slubility f gas in it. When puring liquid metal pushes it cntained air and gas escapes prtective cating frms (permanent A R C H I V E S f F O U N D R Y E N G I N E E R I N G V l u m e 1 1, I s s u e 3 / ,

2 mlds) r gasificatin prcesses, frms f material cmpnents, such as H 2 O (wet mlding). Fr the mst simple gases disslve in cpper and its allys are the O 2 and H 2 [7]. Hydrgen is likely t disslve in metals than the cmpunds frmed with them, while the xygen in the metals disslved in a limited way, and as a result f its excessive frms f metal xides in particular. Present in brnze Sn, Al, Si, Pb and Zn reduce the slubility f hydrgen in liquid cpper, and Ni, Mn and Fe lead t the increase in [8]. Allying elements made t the cpper effect n the decreased activity f cpper in the disslved xygen [9]. As a result f changes in thermdynamic cnditins in the melt caused by the cling and crystallizatin prcess fllwed by desrptin - gas release [7]. The gas released frm the liquid ally, diffuses tward the free surface and is islated in the frm f adsrbed layers, r is trapped inside the ally in the frm f gas cavity. Cnvective mtin f liquid ally in the muld and slid inclusins, prly r nt at all wettable, prmte the release f gas cavities arund them. Thermal cnductivity f simple gases f H 2 are respectively λ=0,185 W/(m*K), O 2 λ=0,0265 W/(m*K) [10] and fr the brnze CuAl10Ni4Fe4 λ=180 W/(m*K) [8]. Due t the fact that the thermal cnductivity f H 2, and the mre O 2 is much smaller than fr the brnze, the increase in the cncentratin f disslved gases in brnze reduces its thermal cnductivity. Fig. 1. Casting pattern in the shape f plates t evaluate the prsity 2. Research methdlgy Brnze CuAl10Ni5Fe5 drwned in a labratry crucible inductin furnace with a capacity f 15 kg and frequency f 8 khz. Whenever the input charcal sprinkled with the task f limiting access f xygen t the liquid ally. Ally withut allying withstand a temperature f 1200 C ± 15 C, and with the additin f Cr, M, W and/r Si at 1300 C ± 15 C. The slag cvering - refining UNITOP BA-1 was inserted as fllws: half the slag was added t the s-called cld charge, and the rest after melting the charge. After melting brnze and isthermal hlding remved slag and refined N 2 fr 5 min. Then insert 0.6% n the weight f metal charge mdifier Aluminum - Beryllium 5%, waited three minutes and pured the sand mld In Figures 1 4 shws the casting patterns fr testing the impact f the chemical cmpsitin f brnze, respectively: prsity - casting pattern plate-shaped (hxlxl = 10x100x100 mm, A = 10 mm Fig. 1), vlumetric shrinkage - casting pattern in the shape f a truncated cne (DxH = 38x46 mm, α = 88 - Fig. 2), linear hindered shrinkage - casting pattern in shrink-shaped frame (L 0 = 145 mm Fig. 3), prne t cracking - casting pattern shaped beams (hxaxl = 4x22x100 mm Fig. 4). Fig. 2. Casting pattern t evaluate the vlumetrick shrinkage Fig. 3. Casting pattern frame t evaluate the linear hindered shrinkage Fig. 4. Casting pattern in the shape f the beam t evaluate the prne t ht cracking 200 A R C H I V E S f F O U N D R Y E N G I N E E R I N G V l u m e 1 1, I s s u e 3 / ,

3 The study was cnducted n the gas pres metallgraphic micrscpe at a magnificatin f x400, watching when sanded and etched surface f crss-sectins in designated areas (2-2, 2-9, 9-2, 9-9, 5-5 Fig. 1). Cmparisns determined the number and type f the gas pres per 1 cm 2 f area. T assess the pres size f the gas and cunting, and calculatin f surface cntractin Svp test prgram was used MultiScanBase brnze. It allws the measurement f parameters analyzed, subject t the selected scale, using the methd f digital image analysis. Vlumetric shrinkage Sv in % was determined frm the equatins (1-4) fr shrinkage cavity shape respectively [11]: cylinder 2.1. The results Figure 5 shws a representative surface f the test casting f aluminum- irn-nickel brnze, in the shape f plates, after grinding. The vast majrity f macr studies, there were n macrcracks r macrprsity in cast plates at the bttm f the surface (Fig. 5 a). On the upper surface f the plates were identified frm 3 t 20 with a maximum macr-pres surface f each f them less than 3 mm 2 (Fig. 5 b). Table 1 shws the results f the measurement f quantity f pres and area pres, frm five measuring windws. Bx and whiskers plts fr selected grades studied brnze shwn in Figure 6. The descriptive statistics presented pres surface area (Tab. 1, Fig. 6) shws that the size f these areas are nn-nrmal distributin - the arithmetic mean is significantly different frm the median. It was frm here als accepted, that the median characterizes the predminant size plenty f pres in studied brnzes. Make additin t the brnze W, M r Cr in shrt supply increases with a median f mm 2, fr the brnze CuAl10Fe5Ni5 t mm 2 after the insertin f allying elea) b), (1) cne truncated cne: with a cnstant diameter djs=0.3 cm, with a cnstant diameter djs=0.8 cm,, (2), (3), (4) where: Djs diameter f the shrinkage cavity in the shape f a cylinder r cne, r greater diameter f a truncated cne, cm, djs smaller diameter f truncated cne, cm, Svp surface shrinkage, %. Surface shrinkage Svp f the cast can be described with the relatin 5: c), (5) where: P1 crss-sectinal areas f the casting with shrinkage cavity, cm 2, P crss-sectinal areas f the casting withut shrinkage cavity, cm 2. Linear shrinkage in % were determined frm the equatin (6): where: L distance between markers fr the frame pattern f linear shrinkage, cm, L distance between markers fr the casting f linear shrinkage, cm. The tendency t ht cracking was evaluated macrscpic studies, identifying the macr-cracks n the surface f casting in the shape f beams. (6) Fig. 5. Area studied aluminum-nickel-irn brnze casting f - shaped plates, after grinding: a) lwer plate surface, b) the upper surface f the plates c) macr pre - a picture measuring windw, 10x10 mm A R C H I V E S f F O U N D R Y E N G I N E E R I N G V l u m e 1 1, I s s u e 3 / ,

4 Ally Number f cunts frm 5 measuring windws Arithmetic mean Median 25th percentyl 75th percentyl Min. Max. Range Average number f pres ments investigated. Increasing the size f the pre surface area f 75% percentile f mm 2 t mm 2. The increase in surface area reduces the amunt f pres in brnze, per 1cm 2 f area, with 55 pres fr the brnze CuAl10Fe5Ni5 t Table 1. Characteristics f the measurement vlume and pre size in the studied grades f brnze: number f cunts, arithmetic mean, median, 25 th percentile, 75 th percentile, min., max. range, average number f pres mm 2 1/cm 2 CuAl10Fe5Ni CuAl10Fe5Ni5W CuAl10Fe5Ni5M CuAl10Fe5Ni5Cr CuAl10Fe5Ni5Cr1.5Si CuAl10Fe5Ni5 CuAl10Fe5Ni5W0.2 CuAl10Fe5Ni5M1.5 CuAl10Fe5Ni5Cr1.5 CuAl10Fe5Ni5Cr1.5Si1.5 median 25%-75% min-max Fig. 6. Bx and whiskers plts fr measuring the amunt and pres size f the grades tested brnze 202 A R C H I V E S f F O U N D R Y E N G I N E E R I N G V l u m e 1 1, I s s u e 3 / ,

5 The increase in pres size f gas and shrinkage in the test brnze while reducing their number, is prbably due t the fact that yu made additins f Cr, M and/r W by disslving in the crystallizing phases in the brnze (κ Fe(Ni), α), r creating new phase (primary intermetallic phases cntaining Cr, M, W), disslved in favr desrptin brnze primarily f hydrgen and reduce the slubility and/r activity in brnze. Make additin silicn t brnze CuAl10Fe5Ni5 reduces the pres size f the gas (median cm 2 ), while increasing their number t 56 pre/cm 2. Descriptive statistics fr brnze while the additin f Cr and Si are amng the smallest value f the test statistics fr the brnze (Tab. 1, Fig. 6). Prbably this is due t the fact that aluminum and silicn nt nly reduces the slubility f hydrgen in cpper, but als in her allys, which are tested multicmpnent brnzes. Multiplying the median, characteristic fr each set f measurements - t be examined brnze - by the average number f pres gas and shrinkage per 1 cm 2 shws that the area per pres in the examined brnzes, cntends that: a) b) fr CuAl10Fe5Ni5 abut 1.17 cm 2 (which represents abut 1.17% f the test surface casting), fr CuAl10Fe5Ni5W0.2 abut 1.04 cm 2, fr CuAl10Fe5Ni5M1.5 abut 1.06 cm 2, fr CuAl10Fe5Ni5Cr1.5 abut 1.13 cm 2, fr CuAl10Fe5Ni5Cr1.5Si1.5 abut 0.83 cm 2. Have been identified that the Gamma prbability distributin, can describe the prbability f pres gas and shrinkage, with a specific surface area in the studied types f brnze. Figure 7 (a c) are shwn fr the brnze CuAl10Fe5Ni5 representative theretical Gamma distributin f significant parameters f the statistics. The prcess f creating a shrinkage cavity in casting test in tw stages. In the first stage creates a cavity shrinkage, frm the free side casting test in the shape f a truncated cne, with a diameter f 3.6 cm and a height f 0.3 cm [11]. It was assumed that the emerging at this stage f vlumetric shrinkage, shrinkage cavity, has a cnstant shape fr all investigated grades f brnze. In the secnd stage f the emerging f shrinkage cavity, it is increasing tward the center f the casting heat, in the shape: cylinder, cne r truncated cne. Figures 8 10 shws crsssectins f the test castings with shrinkage cavity in the shape respectively: c) cylinder cne truncated cne - Fig. 8 (a i), - Fig. 9 (a e), - Fig. 10 (a c). Analyzing the heat exchange in a slidify brnze- a muld sand shuld be expected that in the casting during slidificatin, the crystallizatin frnt in the frm f vault frm the bttm f the cylinder will mve in tw directins, accrding t the casting axis (cylindrical) and in directin f heat center casting (bttm cylinder). Fig. 7. Characteristics f the prbability distributin f pres size measurements fr the brnze CuAl10Fe5Ni5: a) histgram and the fitted prbability distributin, b) the prbability distributin matched the distributin functin, c) the prbability - prbability plt A R C H I V E S f F O U N D R Y E N G I N E E R I N G V l u m e 1 1, I s s u e 3 / ,

6 a) b) a) b) c) d) c) d) e) f) e) g) h) i) Fig. 8. The sectins f test casts with shrinkage cavity in the shape f a cylinder: a) CuAl10Fe5Ni5Cr0.6Si0.4, b) CuAl10Fe5Ni5Cr0.9Si0.7, c) CuAl10Fe5Ni5Si0.7M0.4, d) CuAl10Fe5Ni5Si0.7W0.3, e) CuAl10Fe5Ni5M0.3, f) CuAl10Fe5Ni5W0.1, g) CuAl10Fe5Ni5Cr0.1, h) CuAl10Fe5Ni5Si1.5Cr0.7, i) CuAl10Fe5Ni5Si1.7W0.4 Fig. 9. The sectins f test casts with shrinkage cavity in the shape f a cne: a) CuAl10Fe5Ni5Si1.6M, b) CuAl10Fe5Ni5W0.2, c) CuAl10Fe5Ni5, d) CuAl10Fe5Ni5Cr0.5, e) CuAl10Fe5Ni5Si0.1W0.1 Cnsequently, this kind f mvement f the crystallizatin frnt will be created shrinkage cavity in shape f cylinder. The ccurrence f shrinkage cavity in the shape f a cne r truncated cne, prbably caused by interference in mvement f the crystallizatin frnt caused by: fluctuatin f temperature and density f the ally during slidificatin, the lcal change in thermal cnductivity f brnze as a result f the gassing. There was n shrinkage cavity shape depending n the chemical cmpsitin f the test brnze. Shrinkage prsity and prsity resulting frm the gassing brnze mainly lcates directly belw the cavity shrinkage in the heat center f casting test. This is due t the fact that in the area immediately surrunding the heat center f the casting, brnze the lngest is in the liquid state, and therefre, the gas pushed t the frnt f crystallizatin is trapped in this area, slidify as the last vlume f the casting. The methd f measurement, using digital image analysis, sectin area P f the casting withut shrinkage cavity, the sectin area P1 f the casting with shrinkage cavity, the surface area f shrinkage prsity and gas Ppr and diameter Djs cne shrinkage cavity is shwn respectively in Figures 11 (a d). Table 3 shws: the measurements f the areas P and P1, calculate the surface shrinkage Svp and n the basis f calculating the f vlumetric 204 A R C H I V E S f F O U N D R Y E N G I N E E R I N G V l u m e 1 1, I s s u e 3 / ,

7 shrinkage Sv, area f prsity Ppr, the characteristic dimensins f the shrinkage cavities Djs, djs and linear shrinkage s. Vlumetric shrinkage Sv determined, depending n the stage f creating f a shrinkage cavity and its shape, frm equatins (1), (2), (3) r (4). a) b) c) Fig. 10. The sectins f test casts with shrinkage cavity in the shape f a truncated cne: a) CuAl10Fe5Ni5Si0.1, b) CuAl10Fe5Ni5M0.4, c) CuAl11Fe5Ni5 Figure 12 shws a summary f changes range f vlumetric shrinkage Sv, linear shrinkage s and the field shrinkage and gas prsity Ppr, depending n changes in the CuAl10Fe5Ni5 brnze ally additins ne: Al, Si, Cr, M, W r tgether: Cr-Si, M-Si and W-Si. Fig. 11. Measuring methd: a) crss-sectinal area P f the casting withut shrinkage cavity, b) crss-sectinal area P1 f the casting with shrinkage cavity, c) surface area f shrinkage prsity and gas Ppr, d) diameter f the cne cavity shrinkage Djs A R C H I V E S f F O U N D R Y E N G I N E E R I N G V l u m e 1 1, I s s u e 3 / ,

8 Type f cavity shrinkage (* Type f cavity shrinkage (* Table 2. Crss-sectinal area: the casting withut shrinkage cavity P, casting with shrinkage cavity P1, the area shrinkage and gas prsity Ppr, surface shrinkage Svp, vlumetric shrinkage Sv (at varius stages f the frmatin f shrinkage cavities), linear shrinkage s Stage I Stage II Ally P Ps Svp Djs Sv_I P1 Svp Djs djs Sv_II Sv Ppr s cm 2 % cm % cm2 % cm % % cm 2 % CuAl10Fe5Ni s s CuAl11Fe5Ni s sc CuAl10Fe5Ni5Si s sc CuAl10Fe5Ni5Cr s s CuAl10Fe5Ni5Cr s w CuAl10Fe5Ni5Cr0.6Si s w CuAl10Fe5Ni5Cr0.9Si s w CuAl10Fe5Ni5Si1.5Cr s w CuAl10Fe5Ni5M s w CuAl10Fe5Ni5M s sc CuAl10Fe5Ni5Si0.7M s w CuAl10Fe5Ni5Si1.6M s s CuAl10Fe5Ni5W s s CuAl10Fe5Ni5Si1.7W s w CuAl10Fe5Ni5Si0.1M s s CuAl10Fe5Ni5Si0.7W s w CuAl10Fe5Ni5W s w s cne, sc, truncated cne, w - cylinder Frm the data shws that the change in the chemical cmpsitin f the test brnze significantly affect the vlumetric shrinkage and linear. The ccurrence f gas prsity in brnze and shrinkage, reducing the impact n bth the f vlumetric shrinkage and linear shrinkage. Figure 13 shws the data frm Table 2 (Sv, s, Ppr) srted the increasing f the prsity area Ppr that, whatever the chemical cmpsitin f brnze, with increasing area, Ppr there is a tendency t reduce bth the f vlumetric shrinkage, Sv and the linear s. Fr test grades f CuAl10Fe5Ni5 brnze with additins f Cr, M, W and / r Si casting cracks were nt bserved in the shape f the test beams (Fig. 4). It is therefre cncluded that the allying elements inserted des nt increase susceptibility t ht cracking f cast frm the test brnze. Fig. 12. The ranges f variatin: f vlumetric shrinkage Sv, linear shrinkage s and area f gas prsity and shrinkage Ppr fr the brnze CuAl10Fe5Ni5 variable cntents f the elements: Al, Si, Cr, M and W placed n the amunts f ally 206 A R C H I V E S f F O U N D R Y E N G I N E E R I N G V l u m e 1 1, I s s u e 3 / ,

9 3. Cnclusins The study CuAl10Fe5Ni5 brnze and additins f Cr, M, W and/r Si t the fllwing cnclusins: in relatin t the prsity f castings: f shrinkage and gas cavity frmed in the upper part f the cast test, n the upper surface f the cast is frm 3 t 20 macr-pres area f less than 3 mm 2 each, the prbability f micrpres with an area f mm 2 can be described by the Gamma distributin, median value f the srted set f measurements f the pres area is characterized by the size f the fullest shrinkage pres and gas in the test brnze, Cr, M, W and Si reduces the surface area f gas pres and shrinkage in the tested brnze; Fig. 13. The trends vlumetric shrinkage Sv and linear shrinkage s depending n the value f the prsity area Ppr srted in ascending rdermethd f digital image analysis test casting surface can be invisible t the naked eye t identify micrpres in relatin t vlumetric shrinkage: the cast test develpment prcess shrinkage cavity tw stages, the first stage shrinkage cavity frmed in the shape f a cne with a diameter f 36 mm and a height f 3 mm, and the secnd shrinkage cavity shaped: cylindrical, cne r truncated cne, methd f digital image analysis can determine the shrinkage surface Svp lngitudinal sectins f the test castings axially symmetric, using the develped mdels, based n the surface shrinkage Svp can be determined vlumetric shrinkage Sv brnze, change the chemical cmpsitin f brnze strngly influences the change f vlumetric shrinkage Sv and linear s, increase the prsity area Ppr affects the reductin f vlumetric shrinkage Sv and linear s, in relatin t prne t ht cracking: there was n tendency t ht cracking test brnze. Acknwledgements The wrk was cnducted in the frames f the research prject N N financed with the surces fr the science in the years by the Ministry f Science and Higher Educatin. A R C H I V E S f F O U N D R Y E N G I N E E R I N G V l u m e 1 1, I s s u e 3 / ,

10 References [1] B. Pisarek: The crystallizatin f the brnze with additins f Si, Cr, M and/r W, Archives f Materials Science and Engineering, vl. 28, Issue 8, p , August [2] B. Pisarek: Influence Cr n crystallizatin and the phases transfrmatins f the brnze BA1044, Archives f Fundry Engineering, vl. 7, Issue 3, p , July-September [3] B. Pisarek: Abrasive wear f BA1055 brnze with additives f Si, Cr, M and/r W, Archives f Fundry Engineering, vl. 8, Issue 3, p , July September [4] B. Pisarek: The influence f wall thickness n the micrstructure f brnze BA1055 with the additins f Si, Cr, M and/r W, Archives f Fundry Engineering, vl. 8, Issue 4, p , Octmber December [5] B. Pisarek: The influence f wall thickness n the micrstructure f brnze BA1055 with the additins f Si, Cr, M and/r W, Archives f Fundry Engineering, vl. 8, Issue 4, p , Octmber December [6] B. Pisarek: Influence f the technlgy f melting and inculatin preliminary ally AlBe5 n change f cncentratin f Al and micrstructure f the brnze CuAl10Ni5Fe4, Archives f Fundry Engineering, vl. 10, Issue 2, p , April-June [7] Z. Górny, J. Sbczak: Mdern materials casting n the basis f nn-ferrus metals, ZA-PIS, Kraków 2005 (in Plish). [8] F. N. Streltsv et al.: Lit. Prizv. 2, p , [9] D. Janke, W.A. Fischer: Metall 29, 12/1975, s [10] W. Mizerski: Tables chemicals, Wydawnictw Adamantan, Warszawa 1997 (in Plish). [11] B. Pisarek: Simulatin f vlumetric shrinkage Sv and surface shrinkage Svp, Wyskjakściwe Technlgie Odlewnicze, Materiały I Odlewy, PAN, p , Katwice Gliwice A R C H I V E S f F O U N D R Y E N G I N E E R I N G V l u m e 1 1, I s s u e 3 / ,