Yüksek Mukavemetli Çeliklerde Geri Esnemenin Kalınlık Azaltma Yöntemi ile Telafisi

Öz

Sac metal bükme işlemi sac metal üretiminde önemli bir rol oynar ve geri esneme bu işlemin istenmeyen bir sonucudur. Geri esneme miktarı bilinmeden bükme kalıbı işlemi yapılırsa, kabul edilebilir tolerans değerleri içinde parça üretmek zorlaşır. Bükülecek parçanın geri esneme davranışı da bükme kalıbının boyutunu etkiler. Özellikle 90° U bükme kalıbı söz konusu olduğunda, geri esneme kompanzasyonu yöntemiyle bükme kalıbının üretim maliyeti yüksektir. Bu nedenle, tasarım aşamasında geri esneme değerinin tahmin edilmesi önemlidir. Bu çalışmada, yüksek mukavemetli saclarda kalınlık azaltma yöntemi kullanılarak geri esneme değerini azaltmak için deformasyon miktarının tahmini yapılmıştır. Bu çalışmaya göre kalınlık azaltma yöntemi geri esneme kompanzasyonunda etkin bir şekilde kullanılabilir. Tasarım aşamasında ölçüm doğruluğunun tahmin edilmesi, bükme kalıbının maliyetini düşürür ve fazla deneye gerek kalmadan tolerans limitleri dahilinde parçalar üretmek mümkündür. Sonuçlar, 0,2 t değerindeki kalınlık azalmasının U-bükme işleminde geri esneme değerini ortadan kaldırmak için uygun olduğunu göstermiştir. Deneysel, ampirik ve sonlu elemanlar sonuçlarının birbirine yakın olduğu tespit edilmiştir.

Anahtar Kelimeler

• Bükme
• geri yaylanma
• yüksek mukavemetli çelik
• U-bükme
• kompanzasyon
• kalınlık azaltma.

Compensation of Springback for High Strength Steels by Thickness Reduction Method

Öz

The sheet metal bending process plays an important role in sheet metal production and springback is an unintended consequence of this operation. If the bending die process is performed without knowing the amount of springback, it is difficult to produce parts within acceptable tolerance values. The springback behavior of the part to be bent also affects the size of the bending die. In particular, in the case of a 90° U bend die, the manufacturing cost of the bending die with the springback compensation method is high. Therefore, it is important to estimate the springback value at the design stage. In this work, the estimation of the amount of deformation to avoid springback value was performed using the thickness reduction method for high strength sheet metal. According to this study, the thickness reduction method can be used effectively in springback compensation. The estimation of the measurement accuracy at the design stage reduces the cost of the bending die and it is possible to produce parts within tolerance limits without much experimentation. The results showed that thickness reduction at the 0,2 t value was suitable to eliminate the springback value in the U-bending process. It has been found that experimental, empirical and finite element results are close to each other.

Anahtar Kelimeler

• Bending
• springback
• high strength steel
• U-bending
• compensation
• thickness reduction.

Kaynakça

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