APPLICATION OF FUZZY STATISTICAL PROCESS CONTROL FOR A MANUFACTURING OF GG25 GRAY CAST IRON MATERIAL

Öz

   The group of ferrous materials with more than 2% carbon in their chemical composition is commonly referred to as cast iron materials. Carbon Equivalent (CE) is an empirical value in weight percent, relating the combined effects of different alloying elements used in the making of cast iron to an equivalent amount of carbon. Statistical process control (SPC) can be applied in plants to obtain good quality and high standard products which have become very popular in many industries. Fuzzy process capability analysis by using X-R control charts gives more realistic results, developed with fuzzy theory. Fuzzy control charts are more sensitive than SPC. This study contains construction of a system design to observe whether the conditions of an alloy production line are within the specification and control limits. To determine the average percentage of CE values, the fuzzy X-bar and R charts were applied to GG25 gray cast iron samples for 20 days’ production. In order to control the process parameters and improve quality of the cast products, the comparison of the statistical and experimental results show that the fuzzy SPC methods can be simply applied on a foundry.

Anahtar Kelimeler

• GG25 gray cast iron,carbon equivalent,fuzzy statistical process control

GG25 GRİ DÖKME DEMİR MALZEMESİNİN ÜRETİMİNDE BULANIK İSTATİSTİKSEL PROSES KONTROLÜNÜN UYGULANMASI

Öz

   Kimyasal bileşimlerinde %2'den fazla karbon içeren demirli malzemeler grubuna yaygın olarak dökme demir malzemeleri denir. Karbon Eşdeğeri (CE), dökme demir üretiminde kullanılan farklı alaşım elementlerinin kombine etkilerini eşdeğer miktarda karbon ile ilişkilendiren, ağırlık yüzdesi olarak ampirik bir değerdir. İstatistiksel proses kontrol (SPC), çok popüler hale gelen kaliteli ve yüksek standartlı ürünler elde etmek için fabrikalarda yaygın olarak uygulanmaktadır. Bulanık proses kontrol analizi, X-R kontrol çizelgelerini kullanarak, bulanık teori ile geliştirilmiş daha gerçekçi sonuçlar veren bir tekniktir. Bu çalışma, bir gri dökme demir üretim hattı koşullarının, şartname ve kontrol sınırları dâhilinde olup olmadığını bulanık istatistiksel proses kontrol tekniği ile gözlemlemek için gerçekleştirilmiştir. Bulanık X-R grafikleri, 20 günlük üretim için GG25 gri dökme demir numunelerine uygulanmıştır. Sonuçlar, bulanık istatistiksel proses kontrol (SPC) yöntemlerinin bir dökümhaneye basitçe uygulanabileceğini göstermektedir

Anahtar Kelimeler

• GG25 gri dökme demir,karbon eşitliği,bulanık istatistik kontrol

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