Pik cam kalıp malzemelerinin metalurjik yapılarının kalıp performansına etkisi
The effects of six different alloyed cast irons of metallurgical structures
- Tez No: 68906
- Danışmanlar: DOÇ. DR. KELAMİ ŞEŞEN
- Tez Türü: Yüksek Lisans
- Konular: Metalurji Mühendisliği, Metallurgical Engineering
- Anahtar Kelimeler: Belirtilmemiş.
- Yıl: 1997
- Dil: Türkçe
- Üniversite: İstanbul Teknik Üniversitesi
- Enstitü: Fen Bilimleri Enstitüsü
- Ana Bilim Dalı: Metalurji Mühendisliği Ana Bilim Dalı
- Bilim Dalı: Üretim Bilim Dalı
- Sayfa Sayısı: 99
Özet
Bu çalışmada 6 farklı bileşimdeki pik kalıp malzemelerinin metalurjik yapılarının kalıp performansına etkisi incelenmiştir. Deneylerde cam ürünün taban profilini oluşturan müldefon kalıp parçasını temsil edecek yapı ve bileşimlerde örnekler kullanmak amacıyla, bu özellikleri verecek şekilde döküm koşullarıyla dökümler gerçekleştirilmiştir. Bu amaçla model dizaynından sonra cam ile temas eden yüzeyi temsil eden döküm yüzeyi 40 mm kalınlıktaki pik malzemeden dökülmüş soğutucu ile temasta olacak şekilde kum kalıba silindirik bloklar dökülmüştür. Döküm sonrası parçaların yapısını tamamıyla ferrite dönüştürmek amacıyla ferritleştirme ısıl işlemi uygulanmıştır. Daha sonra kokilli yüzeyler korunarak çeşitli boyutlarda deney örnekleri talaşlı imalat ile ısıl işlemi yapılmış bloklardan çıkarılmıştır. Bu örneklere sertlik, aşınma ve oksidasyon testi uygulanmış ve metallografik yapıları incelenmiştir. Brinell Sertlik cihazında yapılan ölçümler sonucunda bileşimdeki Cr, Ni, Mo, V, Cu, Ti gibi alaşım elementlerinin miktarı arttıkça sertliğin arttığı gözlenmiştir. Farklı bileşimlerde fakat metallografik yapıları birbirine yakın örnekler üzerinde Al203 esaslı zımparada yapılan aşınma deneyi sonucunda sertlik düştüğünde aşınma direncinin de düştüğü gözlenmiştir. Aynı şekilde laboratuar fırınında yapılan oksidasyon testi ile de fazla aşınmış olan örneklerin fazla oksitlendiği gözlenmiştir. Bileşimin karbon eşdeğeri incelendiğinde 4,3 değeri IXüzerindeki örneklerde karıncalanmaya yol açan iri C tipi grafitlerin oluştuğu gözlenmiştir. Mikro yapı incelendiğinde derin ve sık dokulu D tipi grafite sahip örneklerin zor aşınıp zor oksitlendiği D tipi grafiti yeterince içermeyenlerin ise kolay aşınıp oksitlendiği görülmüştür. Kolay aşınan parçalarda çukurlaşmalar olmuş bunlar oksitlenme için aktif bölge meydana getirmişlerdir. Bu ise kalıp ömrünü kısaltıcı bir unsurdur. Bu özellikler çerçevesinde diğer örneklere göre en yüksek oksidasyon direncine, yeterli sertlik ve aşınma direncine sahip Cr, Ni, Mo ve Ti elementleri ile belirli oranda alaşımlandırılan ve yeterli derinlikte ve sıklıkta D tipi grafite sahip VI no'lu bileşim en uygun pik cam kalıp malzemesi olarak değerlendirilmiştir.
Özet (Çeviri)
Molds that are use to form porison are called glass molds. The molds are placed on machines that are named as IS machine. A material selection is made for the different mold parts based on;. The type and shape of the article to be produced.. Glass production machinery used. Glass production process used The mold material is of primary importance in mold making. For a good mold material, the followings are the most important requirements;. Good heat extraction properties. Resistance to deformation. Resistance to corrosion. Resistance to thermal shock. Resistance to mechanical damage. Good machinability with a good surface finish. Reasonable cost. xiIn spite of the many alternative materials e.g., stainless steel, aluminium bronze that have been tried out by the glass container manufacturers and with the exception of some particular production, Cast iron is still the only material which meets most of the requirements. Ease of castings and ease of machining are two of the principal properties affecting the manufacture of glass mold parts and cast iron possesses both these attributes, thus contributing to it being one of the cheapest materials used for glass mold parts. General properties for optimum glass forming: 1. Heat extraction properties : Glass machine speeds are dependent on the rates at which heat can be extracted from the glass and hence good heat extraction properties are most essential for any mold material. The fact that ferritic cast irons have a higher thermal conductivity than perlitic types is one of the factors which has influenced to prefer ferritic irons. For the same reason, nodular graphite cast iron is not recommended because of its lower thermal conductivity about 20 % than lamellar graphitic cast iron. 2. Ability to take a good surface finish: Coarse graphite (A type) is detrimental to producing a high polish. For this reason cast irons are poured on chills in order to obtain a D type graphite over a thickness of 10-15 mm against the cavity of the mold. Such a close grained structure is desirable for glass molds. xiiMore towards the outside of the molds, an A type graphite structure has to be realised, this result in a better heat conductivity and better mechanical properties of the molds. 3. Growth Resistance The growth of the cast iron is caused by either decomposition of the perlite or by oxidation because of the fully ferritic annealed matrix of cast irons any growth depending on the volume change by breakdown of perlite is excluded. Internal oxidation of a cast iron occurs along the graphite flakes. This is due to the fact that iron expands more when heated than graphite, this produces stresses which tend to loosen the bond between iron and carbon under rapid cyclic heating, which is the case with a mold when it is in service. This loosening of the bond between the iron and carbon makes possible the penetration of the gases and consequently oxidation. It's obvious that a fine undercooled graphite reduces this tendency to a minimum. 4. Corrosion Resistance It is well known that a mold iron after some service is covered with an oxide layer is detrimental to the finish of the glass article and mold cleaning is necessary. In order to give optimum resistance to the oxidation, cast irons have the graphite at the surface in fine undercooled form. X1X15. Thermal Shock Resistance The resistance to thermal shock is very important for cast iron, because of the temperature fluctuations at the mold surface when the mold is in operation. Cast iron with a ferritic matrix and fine undercooled graphite alloyed with titanium and molybdenum gives the most satisfactory results. 6. Machinability A better machinability is obtained by the ferrite annealing process. After the process, there is an equal hardness all through the section of the castings. 7. Reasonable Cost The initial cost of mold materials is obviously of for less importance than the mold cost per bottle produced. Alloyed cast iron fulfills satisfactorily the physical requirements of a mold material at a reasonable cost. Metallurgical requirements to meet properties Cast iron is an alloy of iron containing carbon, silicon and manganese. Alloying elements are added to increase the performance of the cast iron and these are usually nickel, chromium and molybdenum. Also, 0,25 % titanium may be added to promote the formation of the fine flake graphite structures necessary at the glass contact surface to resist premature breakdown. A typical acceptable structure at the glass contact surface consist of ASTM type D graphite flakes of size 7-8 in a ferritic matrix. However, the graphite will coarsen progressively through a series of xivstructures to coarse type A flakes of size 3-5 at the back of the mold section. A fine graphite structure has a lower thermal conductivity than a coarse graphite structure. The presence of alloying elements is necessary to achieve optimum resistance to fire cracking and surface breakdown. In this study, the effects of six different alloyed cast irons of metallurgical structures are examined. Samples that are cast and heat treated are used in experiments. Chemical analysis, hardness, wear and oxidation test are applied to the samples. The results obtained from these experiments are indicated as follows. 1. As the alloying elements eg. Cr, Ni, Mo, V, Ti increase, in different compositions, hardness, wear and oxidation resistance are also increased. 2. As the Ti and Ni quantities increase, chill depth and the density of D type graphite in ferritic matrix increases. 3. When carbon equivalent vlue is over 4,3, there is coarse C type graphite in microstructure. 4. In fast solidifying samples, chill depth gets deeper and deeper and fine D type graphite is found in microstructure. 5. As the D type graphite gets thinner in microstructure, wear and oxidation resistance increases. XV6. When microstructure includes only B and C type graphite, oxidation resistance decreases considerably. 7. In order to have sufficient resistance to wear and oxidation in cast iron glass mold materials, they have to include optimum quantities of Cr, Ni, Mo, Ti. 8. For the high resistance of wear and oxidation, matrix should include 95 % ferrite and at the glass contact surface, there should be D type graphite ASTM 7-8 having a depth of 10-12 mm, towards the inside D+A type graphite ASTM 4-6 and A type graphite ASTM 3-5. These are the most suitable glass mold materials because of including smooth and bright mold surfaces and high thermal conductivity. XVI
Benzer Tezler
- Yüksek enerji depolama yoğunluğuna sahip cam seramiklerin geliştirilmesi ve özelliklerinin incelenmesi
Development of high energy storage density glass ceramics and investigation of the properties
MUSTAFA DURMAZ
Doktora
Türkçe
2023
Metalurji MühendisliğiSakarya ÜniversitesiMetalurji ve Malzeme Mühendisliği Ana Bilim Dalı
PROF. DR. ŞADUMAN ŞEN
- Konjestif kalp yetersizliği olan hastalarda doku doppler ekokardiyografi ile sistolik ve diyastolik dissenkroni tayini
The assignment of systolic and diastolic dyssyncrony with tissue doppler echocardiography in the patients with congestive heart failure
FATİH ÇAM
Tıpta Uzmanlık
Türkçe
2007
KardiyolojiZonguldak Karaelmas ÜniversitesiKardiyoloji Ana Bilim Dalı
Y.DOÇ.DR. NESLİGÜL YILDIRIM
- Yaş yöntemle ITO ince filmlerin üretimi, elektriksel ve optiksel özelliklerinin karakterizasyonu
Wet deposi̇ted processing of ITO thin films and characterization of thei̇r optoelectronic properties
SANEM GÜZELLER
Yüksek Lisans
Türkçe
2016
Fizik ve Fizik Mühendisliğiİstanbul Teknik ÜniversitesiFizik Mühendisliği Ana Bilim Dalı
PROF. DR. ESRA ÖZKAN ZAYİM
DR. REFİKA BUDAKOĞLU
- Effects of raw materials on melt foaming generation in e-glass batch-to-melt conversion process
E-camı harmandan ergiyik hale dönüşüm prosesinde hammaddelerin ergiyik köpük oluşumuna etkileri
GÜLİN DEMİROK
Doktora
İngilizce
2024
Metalurji Mühendisliğiİstanbul Teknik ÜniversitesiMetalurji ve Malzeme Mühendisliği Ana Bilim Dalı
DR. ÖĞR. ÜYESİ NURİ SOLAK
- Termiyonik vakum ark yöntemi ile nanoyapılı çinko sülfür filmlerin elde edilmesi ve bazı fiziksel özelliklerinin belirlenmesi
Production of nanostructured zinc sulfide films by the termonic vacuum arc method and determination of some physical properties
ERSİN KAYA
Yüksek Lisans
Türkçe
2019
Fizik ve Fizik MühendisliğiEskişehir Teknik Üniversitesiİleri Teknolojiler Ana Bilim Dalı
PROF. DR. METİN KUL