Overviewofcastingdefects鑄件缺陷en-ch

1、Slide No. 1 J.Vierimaa Overview of casting defects 鑄件缺陷的概述鑄件缺陷的概述 / J.VierimaaSlide No. 2 J.VierimaaOverview of casting defects 鑄件缺陷的概述鑄件缺陷的概述The general origins of casting defects導(dǎo)致鑄件缺陷的幾大根源- casting design鑄件的設(shè)計鑄件的設(shè)計- technique of manufacture = method -生產(chǎn)技術(shù)生產(chǎn)技術(shù)=方法方法- application of the technique =

2、workmanship -技術(shù)的實施技術(shù)的實施=作業(yè)過程作業(yè)過程Process steps 工序步驟- Defect recognition 識別缺陷- Defect occurrences 發(fā)生缺陷- Defect removal 解決缺陷Slide No. 3 J.VierimaaExample of casting design-設(shè)計導(dǎo)致產(chǎn)品缺陷舉例設(shè)計導(dǎo)致產(chǎn)品缺陷舉例Plenty of separate bosses which need feeding.單獨的套筒過多，需要很多冒口Slide No. 4 J.VierimaaExample of method-因方法導(dǎo)致產(chǎn)品缺陷舉例因

3、方法導(dǎo)致產(chǎn)品缺陷舉例Put machined surfaces to drag mould ( = face down ) 將加工面放在下模（=加工面朝下）Slide No. 5 J.VierimaaExample of method-因方法導(dǎo)致產(chǎn)品缺陷舉例因方法導(dǎo)致產(chǎn)品缺陷舉例Proper lay-out done before machining / OK.在加工之前需要畫好線/OKBack supports in use to reduce bending due the fixing / OK放置后支撐，防止固定時變形/OKCeramic inserts in use in machi

4、ning / OK加工時使用的陶瓷插件/OKSlide No. 6 J.VierimaaExample of workmanship因作業(yè)過程導(dǎo)致產(chǎn)品缺陷舉例因作業(yè)過程導(dǎo)致產(chǎn)品缺陷舉例Limestone used from broken bags; CaO Ca ( OH )2使用破包裝袋里面取出的石灰石氧化鈣發(fā)生反應(yīng)生成了氫氧化鈣Mould has leaked during pouring due missing clamp.由于夾子不夠，澆注的時候砂型漏鋼水Slide No. 7 J.VierimaaExample of workmanship因作業(yè)過程導(dǎo)致產(chǎn)品缺陷舉例因作業(yè)過程導(dǎo)致產(chǎn)品

5、缺陷舉例Stopper rods not protected with refractory paint塞桿上面沒有刷保護(hù)涂層Pouring done with leaking nozzle.用漏水的鋼包進(jìn)行澆注Slide No. 8 J.VierimaaExample of workmanship因作業(yè)過程導(dǎo)致產(chǎn)品缺陷舉例因作業(yè)過程導(dǎo)致產(chǎn)品缺陷舉例Broken drying hoses in use; hot air leaking out; not going into the mould烘干爐的管子已經(jīng)破損，熱氣在進(jìn)入砂型之前就已經(jīng)跑掉了。No dead end brick; all t

6、he dirty would go into the mould cavity沒有放積渣槽，所有的渣滓會進(jìn)入到型腔內(nèi)。Slide No. 9 J.VierimaaExample of workmanship因作業(yè)過程導(dǎo)致產(chǎn)品缺陷舉例因作業(yè)過程導(dǎo)致產(chǎn)品缺陷舉例Pouring done with leaking nozzle用漏水的鋼包進(jìn)行澆注Pouring cup not protected during coating刷涂料的時候沒有將澆口杯蓋起來Cores not supported; bending, dimensional problems in castings砂芯沒有支撐好。發(fā)生變形

7、，導(dǎo)致澆注之后的尺寸問題。Slide No. 10 J.VierimaaDiagnosis of casting defects 鑄件缺陷的分析鑄件缺陷的分析Do diagnosis 分析- Position of defect 缺陷的位置- Casting traceability 鑄件的可追溯性- Process parameters in production 生產(chǎn)過程的工藝尺寸Correct diagnosis is essential, because it dictates the corrective actions 正確的分析至關(guān)重要，它決定采取正確的行動。Cure for o

8、ne defect can be the cause of another 消除一個缺陷采取的措施可能是導(dǎo)致另一種缺陷產(chǎn)生的原因。Confirmatory tests are important 驗證試驗非常重要。Slide No. 11 J.VierimaaDiagnosis of casting defects 鑄件缺陷的分析鑄件缺陷的分析Some Universities and Reaseach Centres have SEM- ( Scanning Electron Microscopy ) and EDS- ( Energy Dispersive X-ray Spectrosco

9、py ) equipments they can analyse inclusions and help to find right diagnosis 有些大學(xué)和研究中心擁有標(biāo)準(zhǔn)電子微縮設(shè)備（SEM）和能源擴(kuò)散X光分光鏡檢查設(shè)備（EDS）分析雜質(zhì)成分和提供正確的分析In European no-bake steel foundries the internal scrap ratios are around 1,5-2,0 %, customer scrap ratio 0,5 % and usage of welding consumables 2 kg / t 在歐洲，采用自硬工序的鑄鋼

10、廠中，內(nèi)部的報廢率約為1.5%至2.0%，客戶端的報廢率小于0.5%，焊材消耗率小于2公斤/噸。Slide No. 12 J.VierimaaChemical composition of the surface defects缺陷表面的化學(xué)成分缺陷表面的化學(xué)成分The use of Scanning Electron Microscope (SEM) is very helpful to find out the analysis of the surface defects of a casting. The main components of the chemicalanalysis

11、show the origin of the defect: 使用電透鏡可有效分析鑄件表面的缺陷，通過主要成分可找到缺陷的源頭。Al2O3 + SiO2 (approx. 1:2) refractory fire clay material ( = gating system) 三氧化二鋁+二氧化硅（大約為1:2）.耐火粘土物(澆鑄系統(tǒng))CaO + M-oxides . . slag from the ladle 氧化鈣+合金氧化物 . 來自鋼包的渣ZrO2 + SiO2 + Me-oxides Coating 氧化鋯+氧化硅+合金氧化物 涂料 SiO2 and/or Cr2O3/Fe2O3

12、. sand erosion 氧化硅和(或)三氧化二鉻/三氧化二鐵 沖砂Al2O3, SiO2, MnO , Fe2O3 high oxide content in the steel 三氧化二鋁，二氧化硅，氧化錳，三氧化二鐵 . 氧化物含量過高。Slide No. 13 J.VierimaaSources for macroinclusions / SFSA產(chǎn)生雜質(zhì)的幾個主要源頭產(chǎn)生雜質(zhì)的幾個主要源頭/SFSAMain reasons for reoxidation 二次脫氧的主要原因二次脫氧的主要原因-throttling in pouring 澆注間斷，不連貫-wrong gating

13、ratios 澆注系統(tǒng)設(shè)計比例不合理-ladle and pouring basin not in line 鋼包出水口澆注時不對齊澆口。Slide No. 14 J.VierimaaDefects in sand cast ( no-bake ) steel castings （自硬式）砂鑄鋼的缺陷 - Common castings defects 常見鑄件的缺陷常見鑄件的缺陷- Causes 原因原因- Prevention 預(yù)防措施預(yù)防措施Slide No. 15 J.VierimaaSurface related defects in sand castings砂鑄產(chǎn)品的外觀缺陷砂鑄

14、產(chǎn)品的外觀缺陷Cold crack 冷裂縫冷裂縫Crack ( not oxidized ) in cold cast metal due to high internal residual stresses caused by由于內(nèi)部殘余應(yīng)力過高產(chǎn)生冷裂，原因是：-Unsuitable casting design 鑄件設(shè)計不合理-Rough handling 野蠻裝卸/搬運-Restricted metal contraction 鑄件收縮受阻-Improper heat-treatment procedure 熱處理工藝不當(dāng)Prevention 預(yù)防-Handle castings wi

15、th care 搬運工廠中要特別小心-Minimize flash around mould joints and core prints ( flash = acts like cooling rib or chill )-將砂型和芯頭連接處的披鳳最小化（披鳳=起冷鐵和冷卻拉筋的作用）-Ensure good mould breakdown properties, use less binder in sand, use hollow cores 確保良好的脫模性，使用較少的樹脂，空心化砂芯-Prevent stress raisers surface defects ( = startin

16、g point for crack )防止應(yīng)力提升-表面缺陷（=開裂點）-Reduce residual casting stresses by new design, use progressive section thickness changes-采用新設(shè)計以減少鑄件的殘余應(yīng)力，采用漸變壁厚。-Check the metal raw materials; avoid sulphur ( S ), phosphor ( P ), carbon ( C ) 檢查原材料：避免含硫、磷和碳Slide No. 16 J.VierimaaSurface related defects in sand

17、 castings 砂鑄產(chǎn)品的外觀缺陷砂鑄產(chǎn)品的外觀缺陷Cold lap 冷隔冷隔Marks on the casting skin in the form of wavy folds which in some cases show the direction of the liquid metal flow. 鑄件表面有波紋狀的痕跡，有時痕跡表明鋼液流動的方向。-Inadequate or badly designed gating system 澆注系統(tǒng)設(shè)計不良-Too thin wall thickness-design 鑄件壁厚設(shè)計過薄-Pouring temperature too

18、 low 澆注溫度過低-Interrupt / bad pouring 澆注間斷/不當(dāng)-Pouring with leaking nozzle用漏水的出水口澆注-Ladle not in-line above pouring cup鋼包和澆口杯未對齊Prevention 預(yù)防預(yù)防-Use well designed gating system, avoid turbulence ( steel flow 25 kg / s ) 盡快澆注，無間斷（大于25）-Check the gating ratios ( bottom pouring 1:2:4:4 )檢查澆注系統(tǒng)的通道比例（底注式1:2:

19、4:4）-Pour the moulds “ uphill “ or thin castings on vertical position.那些向上的砂型或較薄的鑄件需要在垂直的位置進(jìn)行澆注-If too thin design add thickness and / or fins 如果設(shè)計過薄增加尺寸厚度-Increase pouring temperature 提高澆注溫度-Avoid high residual aluminium ( Al ) in de-oxidation, increase silicon ( Si ) 避免脫氧時殘余鋁過高，增加硅含量Slide No. 17 J

20、.VierimaaSurface related defects in sand castings 砂鑄產(chǎn)品的外觀缺陷砂鑄產(chǎn)品的外觀缺陷Sand burn-in燒砂燒砂A fused layer of sand adhering firmly to the surface of the casting, particularly in thick metal sections or where thin sections of mould or core are surrounded by metal鑄件表面牢牢粘附一層已燒化的砂,特別是鑄件較薄部分或者模和芯環(huán)繞的較薄的部分。-Poor co

21、mpaction.舂砂不嚴(yán)實-Impurities in silica sand ( CaO, K2O, Na20 ).硅砂里面有雜質(zhì)Contamination of sands by iron oxide etc 氧化物致使砂受到污染-Poor coating quality and practice 刷涂層操作不當(dāng)-Too high pouring temperature 澆注溫度過低Prevention 預(yù)防預(yù)防-Use higher quality silica sand ( SiO2 minimum 98-99 % ) 使用高質(zhì)量的硅砂（二氧化硅）-Check the sulphur

22、 ( S ) content of the reclaim sand; ought to be 25 kg / s ) 盡可能使用最低的澆注溫度；保持較好的鋼液流動性（大于25千克/秒）-Modify gating system, avoid hot spots 修改澆注系統(tǒng)，避免出現(xiàn)熱節(jié)Slide No. 18 J.VierimaaSurface related defects in sand castings砂鑄產(chǎn)品的外觀缺陷砂鑄產(chǎn)品的外觀缺陷Prevention 如何預(yù)防如何預(yù)防-Ensure sand to sand contact on parting line 確保合模良好，在分型

23、線中無縫隙-Repair the damages of flasks ( add sand retaining ribs, clean flask joint faces etc ) 修補(bǔ)砂箱（ ）-Use rigid bottom boards and check the flatness of the patterns 使用剛性底板，并檢察平整度-Support the cores in storage 砂芯在存放過程中放置支撐-Avoid excessive coating of core prints 芯頭勿涂過多涂料-Use minimum fillets around the co

24、re prints 使用芯頭無尖角、邊的的砂芯-Ensure adequate weighting / clamping prior to pouring 澆鑄前確保適當(dāng)?shù)刂亓亢蛫A緊-Check that the floor is straight and better to have some layer of sand on it 檢查地面平整是否，最好有層砂Flash 披鳳披鳳Projections in the form of metal wafers of varying thickness occurring at mould joints, around core prints

25、or between mould and core joints.鋼液在分型線濺出，在芯頭或者上下模和芯之間形成不均的薄片-Damaged moulding boxes 損壞模具盒-Lack of reinforcing bars in flasks 砂箱中未放置加強(qiáng)筋-Incorrect seating of cores in prints 芯頭放置不正確Slide No. 19 J.VierimaaSurface related defects in sand castings砂鑄產(chǎn)品的外觀缺陷砂鑄產(chǎn)品的外觀缺陷Hot tear 熱裂熱裂Tear occurring during soli

26、dification process, distinguished from a cold crack by an oxide skin at its crack surface. 鑄件在固化過程中出現(xiàn)了熱裂，與冷裂的區(qū)別是熱裂縫表層有一層氧化的表層-Restraint to contraction by the mould / core 限制砂模/砂芯的收縮-Poor design of casting 澆注系統(tǒng)設(shè)計不恰當(dāng)-Premature shake-out 震砂過早-High pouring temperature 澆注溫度過高Prevention 預(yù)防預(yù)防-Modify castin

27、g design to avoid heavy sections; add several ingates 修改鑄件設(shè)計；增加內(nèi)澆道-Avoid sharp corners, hot spots, chaplets ( = starting point for cracks ) 避免尖角、熱節(jié)、使用芯撐（裂縫的始點）-Ensure good mould breakdown properties, use less binder in sand, use hollow cores 確保震砂性能，減少使用樹脂，使用空心砂芯-Use phenol resin binders instead of s

28、odium silicate or furan 使用苯酚樹脂代替硅酸鈉或者呋喃-Use low pouring temperature but high flow volume ( 25 kg / s ) 降低澆注溫度但增加鋼水流動速度-Let the castings cool down in the sand 鑄件在砂中冷卻到一定的溫度-Have the ferrite content below 50 % in super-duplex steels 在超級雙相鋼中鐵素體的含量小于50%Slide No. 20 J.VierimaaSurface related defects in s

29、and castings砂鑄產(chǎn)品的外觀缺陷砂鑄產(chǎn)品的外觀缺陷Metal penetration 鋼液滲透鋼液滲透A agglomerated layer of sand grains and metal mechanically jointed to the casting surface. 在鑄件表面產(chǎn)生一層砂和金屬機(jī)械地黏在一起-High ferrostatic pressure due pouring from high ladle position 在澆注時鋼水靜壓力過高-High dynamic pressure due to flow characteristics 由于鋼液流動特

30、性，動態(tài)壓力過高-High sulphur ( S ) content in reclaim sand再生砂的硫含量過高-Poor compaction 舂砂不嚴(yán)實-Poor coating涂料沒有刷好Prevention 如何預(yù)防如何預(yù)防-Check the sieve analysis; more than 80 % in 3-4 sieves, average sand grain size around 0,30 mm檢查砂子篩選分析：80%以上的砂應(yīng)該分布在3-4個篩子里面，砂子的平均粒度是0.30mm-Do good compaction of the cores and moul

31、ds 加強(qiáng)砂模和砂芯舂砂嚴(yán)實-Check the viscosity of the coating; use thicker coating檢查涂料的濃度，使用更濃的涂料-Use smaller ladle 使用較小的鋼包-Check the gating ratios ( bottom pouring底注式 1:2:4:4 ) 檢查澆注系統(tǒng)比例-Use well designed gating system, avoid turbulence ( steel flow 38 % Al2O3 ) raw material for ceramic gating tubes 陶瓷澆道管的原材料中鋁

32、含量要高( 38 % Al2O3 ) -Shot-blast the return scrap no sand or ceramics into the furnace ( = reduces also lining lifetime )報廢的回爐料需要拋丸 不要將砂子或陶瓷片混到電爐中（=這材質(zhì)縮短爐齡）-Use male-female connections and masking tape in ceramic tubes 陶瓷管使用公母連接方式和不透光膠紙-Protect ceramic gating systems during coating; use plugs in flow

33、coating 上涂層時要保護(hù)陶瓷澆注系統(tǒng)，流涂要塞住澆口杯-Grind sharp corners away from the cores during assembly and cover ready moulds 合箱時磨去砂芯的尖角Slide No. 23 J.VierimaaSurface related defects in sand castings砂鑄產(chǎn)品的外觀缺陷砂鑄產(chǎn)品的外觀缺陷Finning / Veining 脈紋脈紋Thin, rough and irregular fins of metal projecting from the casting surface;

34、most often in corners ( impeller castings ! ) 在鑄件的外觀可以發(fā)現(xiàn)有一些薄的、粗糙的、不規(guī)則的鰭裝物。常見于轉(zhuǎn)角處（葉輪鑄件）-Silica sand expansion 硅砂擴(kuò)張-Too high sand compaction (core-shooter! ) 砂過于緊實（射芯機(jī)）-Sharp corners 尖角-High pouring temperature 澆注溫度過高Prevention 預(yù)防預(yù)防-Use right ratios of resin:hardener in sands; dont over-cure 使用正確的樹脂、固

35、化劑比例，不能過量調(diào)整-Use as low as possible shooting pressures in core-shooter; 3 bars. 射芯機(jī)壓力盡可能的低一些， 25 kg / s ) to minimize radiation time 增加鋼液流動量( 25千克/秒)減少放射時間Slide No. 24 J.VierimaaSurface related defects in sand castings砂鑄產(chǎn)品的外觀缺陷砂鑄產(chǎn)品的外觀缺陷Misrun 澆不足澆不足Part of the casting is missing usually on the cope s

36、urface. The edges adjacent to the missing parts are rounded and generally shiny. 澆不到的地方，邊比較圓通常會發(fā)光-Pouring temperature too low 澆注溫度過低-Pouring too slow 澆注速度慢-Slag on metal surface 金屬面有爐渣-Interruptions in pouring 間斷澆注-Ladles nozzle and pouring cup not in-line during pouring 澆注過程中鋼包出水口和澆口杯沒有對齊Prevention

37、 預(yù)防預(yù)防-Increase pouring temperature and flow ( 25 kg/s ) 提高澆注溫度和鋼液流動性-Dont pour over 25 moulds with the same ladle and 10 impeller moulds with one ladle不要用同一包水澆鑄超過25箱鑄件，同一包水也不能澆注超過10個葉輪-Modify the metal composition to add the fluidity; e.g in C-steels less Al in de-oxidation 修改鋼液成分；例如含碳鋼中環(huán)氧中減少鋁含量-Rem

38、ove the slag from metal surfaces 去除鋼液表面的熔渣-Dont interrupt the pouring 勿間斷澆注-If throttling check the gating ratios ( 1:2:4:4 ) 如果出現(xiàn)節(jié)流檢查澆注通道比例-Add dirty traps and air pins 增加集渣槽和排氣棒-Have at least one open feeder and good venting最少保證有一個明冒口和通氣良好Slide No. 25 J.VierimaaSurface related defects in sand cast

39、ings砂鑄產(chǎn)品的外觀缺陷砂鑄產(chǎn)品的外觀缺陷Erosion, wash 腐蝕，洗滌腐蝕，洗滌Projections on the casting surfaces in positions where metal flow hits onto the mould / core surface ( sand inclusion ) 注射的鋼液沖刷砂型/砂芯表面，產(chǎn)生夾砂。-High metal velocity 鋼液流動速度過快-Wrong place for ingates 內(nèi)澆道設(shè)計位置錯誤-Inadequate sand properties 砂性能不當(dāng)-High metal throug

40、hput 金屬吞吐率過高Prevention 預(yù)防預(yù)防-Modify the gating system to reduce concentration of metal flow 修改澆注系統(tǒng)，減小鋼液流動的集中性-Use thicker coating or higher refractory sands ( = ceramic, chromite ) in washed areas在被沖走的區(qū)域使用更厚的涂料和耐高溫的砂（陶瓷砂和鉻礦砂）-Reduce metal velocity in ingates ( 38 % )將澆道系統(tǒng)更換為陶瓷管（Al2O3 含量 38 % )-Use sm

41、aller ladles使用更小的鋼包Slide No. 26 J.VierimaaStructure related defects in sand castings砂鑄產(chǎn)品的結(jié)構(gòu)不良砂鑄產(chǎn)品的結(jié)構(gòu)不良Gas blowholes 皮下氣孔皮下氣孔Cavities occurring at or near casting surface, spherical or elongated and generally having smooth or rounded walls. -Moisture in raw materials 原材料有水分-High humidity 濕度過高-Entrapp

42、ed air 空氣堵塞 -Entrapped gases 氣體堵塞-Fresh cores, moulds not dried 新砂芯、砂型未充分干燥-High L.O.I in reclaim sand 再生砂的燒損量過高Prevention 預(yù)防預(yù)防-Dry all the raw materials ( sand, refractories, feeder sleeves, limestone, scrap etc )烘干原材料（砂子、耐火材、冒口、石灰石、廢品等）-Check the de-dusting, sand reclamation system, binder level a

43、nd usage of new sand to reduce L.O.I 1,0%檢查除塵系統(tǒng)、砂再生系統(tǒng)、樹脂使用量和新砂使用量將燒損量降低到1.0%。-Avoid sharp corners in casting design; super heated core / mould area produces a lot of gas在鑄件設(shè)計時避免鋒利邊角，砂芯和砂型的過熱產(chǎn)生大量的氣體。-Check the feeding system ( = shortage of feeding; under pressure inside the casting favors gas defect

44、s)檢查澆注系統(tǒng)（=澆注不夠、鑄件內(nèi)部帶壓會導(dǎo)致氣體不良）-Avoid turbulence in gating system ( = metal speed 0,5 m / s, proper ratios 1:2:4:4 )、避免澆注系統(tǒng)中出現(xiàn)湍流（鋼液流動速度小于0.5米/秒，比例1:2:4:4）-Avoid throttling in pouring 澆注中避免節(jié)流 -Increase pouring temperature 升高澆注溫度-Do venting holes to cope mould, add venting to cores and have at least one

45、 open feeder 在上模上面打通氣孔，砂芯上面加通氣塞并保證最少有一個明冒口-Pour the dried moulds asap to avoid condensation 應(yīng)盡快對已烘干的砂型澆注以避免冷凝-Check the core print dimensions and the usage of glue / cope seal.檢查芯頭的尺寸、粘膠、油封條的使用情況Slide No. 27 J.VierimaaStructure related defects in sand castings砂鑄產(chǎn)品的結(jié)構(gòu)不良砂鑄產(chǎn)品的結(jié)構(gòu)不良Hydrogen pinholes 氫氣針孔

46、氫氣針孔Small spherical holes just below the casting surface. The holes are often smooth and shiny. 在鑄件表面下微小的球狀孔。小孔平面一般比較光滑，明亮-Low pouring temperature 澆注溫度低-Improper de-oxidation 脫氧不良-Moisture in raw materials 原材料含有水分-Wet moulds / cores 砂模、砂芯含有水分Prevention 預(yù)防預(yù)防-Dry all the raw materials ( sand, refracto

47、ries, feeder sleeves, limestone, scrap etc ) 烘干所有的原材料（砂子、 耐火材、冒口袖、石灰石和廢品等）-Dry all the patchings 烘干所有的修補(bǔ)材料-Use protective slag during melting, avoid high melting temperatures, avoid holding the ready melt 熔煉時使用保護(hù)渣、避免高溫熔煉、避免長時間爐內(nèi)放置.-Use AOD refining and Argon purging in the ladles使用AOD爐并往鋼包內(nèi)吹氬氣-Incre

48、ase pouring temperature 升高澆注溫度-Avoid long gating systems 避免澆注溫度過長-Use CaSi in de-oxidation instead of aluminium ( Al ) 在脫氧中使用硅化鈣代替鋁-Dont use fresh cores and dry moulds long enough不要使用新的砂芯，并充分烘干砂型-Use iron oxide in Cold-Box core sand ( Fe2O3 about 2-5 % weight of the sand ) 在冷芯盒砂芯那里使用氧化鐵（ Fe2O3 的重量占砂

49、重量的2-5%）Slide No. 28 J.VierimaaStructure related defects in sand castings砂鑄產(chǎn)品的結(jié)構(gòu)不良砂鑄產(chǎn)品的結(jié)構(gòu)不良Nitrogen pinholes and fissures氮氣氣孔氮氣氣孔Bright smooth faced surface or sub-surface irregular shaped cavities ( = fissure ) or spherical cavities ( = nitrogen pinholes ) in thick sections. 氣孔表層平整明亮；在較薄的部分的表層下有不規(guī)則

50、的孔或者球狀孔-Excess nitrogen in scrap 回爐料中含氮量過高-High nitrogen sand binders 樹脂中含氮量過高-Poor sand reclamation 砂回收系統(tǒng)運轉(zhuǎn)不良Prevention預(yù)防預(yù)防-Use only low nitrogen binders and coatings in sand 使用氮含量較低的砂和樹脂-Avoid scrap materials with high nitrogen 不使用氮含量過高的回爐料-Check the nitrogen analysis of the spectrometer; combusti

51、on method gives accurate values. 用光譜儀檢查氮元素，燃燒的方法測試的值更加精確-Have nitrogen in duplex- and super duplex steels on the low side.雙面不銹鋼和超級雙面不銹鋼的氮含量應(yīng)該要偏低-Check sand reclamation system, de-dusting and the usage of the new sand; keep Loss of Ignition 1.0 %檢查再生砂系統(tǒng)，除塵系統(tǒng)和新砂的使用量，保證燒損值低于1.0%。-Dont use fresh Cold-Bo

52、x cores; they should be minimum 24 h old .不要使用新的冷芯盒，最少要放置24小時再用。-Cold-Box phenol resin ( Part I) and isocyanate ( Part II ) should be mixed with 1:1 ratio or use the ratio 55:45 to reduce the risk of gas defects ( Isocyanate contains plenty of nitrogen )冷芯盒酚醛樹脂I和異氰酸鹽II需要按照1:1或55:45的比例來配兌使用，這樣可以降低氣體不

53、良的風(fēng)險。-Use FeTi as a de-oxidation material in C-steels to neutralize nitrogen 在碳鐵中，使用鈦鐵為脫氧材料抵消氮。Slide No. 29 J.VierimaaStructure related defects in sand castings砂鑄產(chǎn)品的結(jié)構(gòu)不良砂鑄產(chǎn)品的結(jié)構(gòu)不良Shrinkage / Porosity 縮孔縮孔/縮松縮松Cavities of varying size. Quite often a dendritic structure is evident. The defects occurs i

54、n the last metal to solidify or in centre line.各種形狀的孔。常見的是樹枝形狀。此缺陷出現(xiàn)在鋼液最后凝結(jié)的部分或者在鑄件的中心線部位-Poor casting design 鑄件設(shè)計不良-Lack of sufficient feed metal 補(bǔ)縮不暢-High pouring temperature 澆注溫度過高-Soft mould 砂型硬度不夠Prevention預(yù)防預(yù)防-Use AOD refining and Argon purging in ladles to reduce the gas contents.使用AOD精煉爐并在鋼包

55、內(nèi)吹氬氣來降低氣體含量。-Do filling and solidification simulation with Magmasoft program用邁格瑪軟件模擬充填和凝固過程。-Re-design the casting or use paddings, different casting position etc 重新設(shè)計鑄件或者增加補(bǔ)貼-Check the modulus of the casting : feeder neck : feeder ( should be 1 : 1,1 : 1,3 ). 檢查模數(shù)：鑄件：冒口座：冒口的模數(shù)（應(yīng)該是1:1.1:1.3）-Check f

56、eed volume requirements ( important while using high exothermic feeder sleeves ) 檢查冒口的容積要求（使用高吸熱冒口袖的話，這個因素非常重要）。-Reduce the pouring temperatures; e.g 1500 C is enough for heavy section 1.4460 duplex steel 降低澆注溫度，如：1.4460雙相不銹鋼較厚截面，1500度的溫度就已經(jīng)足夠。-Use chills or chilling sand like chromite in hot spots

57、熱節(jié)部位使用冷鐵或有冷卻作用的砂如鉻礦砂-Have support ribs in flasks and extra steel bars top of flat castings like Kaplan blades to reduce the mould movement 給砂箱加加強(qiáng)筋、在砂箱頂部加鋼條（如軸流轉(zhuǎn)刀片來降低砂型的移動）Slide No. 30 J.VierimaaWorkmanship related defects in sand castings 操作操作致砂鑄產(chǎn)品缺陷致砂鑄產(chǎn)品缺陷Leakage from the mould 跑火（砂型漏水）跑火（砂型漏水）Moul

58、d is leaking during pouring or immediately after the pouring. 澆注過程中或澆注之后，砂型立馬發(fā)生漏鋼問題。Casting is only partly full or has discontinuation marks.鑄件只是部分澆滿或有中斷痕跡-Too narrow free parting line or mould height too small 活動的分型線太窄或砂型的高度太低-No cope seal or adhesive on parting line 在分型線沒有放泥條或其他的粘結(jié)材料-Not enough cl

59、amps or no clamps at all 夾子不夠或根本沒有打夾子-Mould strength too low 砂型的強(qiáng)度太低-No support bars / sand ribs on the flasks or support bar across 沒有支撐塊或砂箱內(nèi)沒有足夠多的支撐故為，沒有交叉支撐骨位-Mould is placed on uneven floor 砂型沒有放置在平整的地面上Prevention預(yù)防措施預(yù)防措施-Have minimum 30 mm sand on parting line and 50-100 mm under the lowest par

60、t of the mould cavity在分型面最少需要30mm的砂，在砂型型腔最低的面有50-100mm的砂。-Have at least one open feeder and venting to reduce the ferrostatic pressure during filling.最少有一個明冒口和通氣孔來減少澆注過程中型腔內(nèi)的壓力-Have clamps enough and especially near the connection of downsprue and runner bar配置足夠的夾子，特別是在澆口杯和橫澆道附近。-If youll hang the c