AZ91 magnezyum alaşımlarının sürtünme karıştırma nokta kaynağı; eksenel kuvvet ve dönme hızının kaynak kalitesine etkisi ve muayene planlamasına ilişkin bir yaklaşım

Öz

Bu çalışmada magnezyum alaşımlı (AZ91) sac malzemeler için sürtünme karıştırma nokta kaynağı işlemi incelenmiştir. Sürtünme karıştırma nokta kaynağı, katı hal kaynak işlemidir ve özellikle otomotiv bileşenlerini birleştirmek için kullanılan yenilikçi kaynak yöntemlerinden biridir. Son yıllarda magnezyum alaşımları, otomotiv uygulamalarına yönelik yapısal malzemelerde araç performansını artırmak ve emisyonları ve yakıt tüketimini azaltmak için yüksek mukavemet ve düşük yoğunluk kombinasyonunun gözlenebildiği umut verici malzemelerdir. Otomotiv uygulamalarında eksenel kuvvet ve dönme hızının malzeme üzerine etkisini anlamak için bir sonlu elemanlar modeligeliştirilmiştir. Sonlu elemanlar modeli ile 1 kN ile 8 kN arasında değişen eksenel kuvvetin ve 1000 rpm - 4000 rpm arasındaki dönme hızlarının etkisini araştırılmıştır. Model, işlem sonrasında süreksizlik oluşumuna yol açan ısı akışını ve sıcaklık artışını analiz etmektedir. 4,5 kN, 6 kN ve 8 kN eksenel kuvvetler ve 3000 rpm-4000 rpm dönme hızları, belirlenen sınır şartları altında süreksizlik oluşumu açısından kritik işleme parametreleri olarak değerlendirilmiştir. Son olarak, sürtünme karıştırma nokta kaynağı işleminden sonra yüzey ve hacimsel süreksizliklerin zararlı etkilerini ortadan kaldırmak için ve yapısal bütünlüğü sağlamak amacıyla çeşitli tahribatsız muayene yöntemleri önerilmiştir.

Anahtar Kelimeler

• Sürtünme karıştırma nokta kaynağı
• Sonlu elemenalar analizi
• Magnezyum alaşımı (AZ91)
• Eksenel kuvvet
• Dönme hızı
• Tahribatsız muayene

Friction stir spot weld (FSSW) of AZ91 magnesium alloys; effect of axial force and rotational speed on weld quality and an approach on inspection planning

Abstract

In this study, the friction stir spot welding (FSSW) process for the magnesium alloy (AZ91) sheet materials are investigated. Friction stir spot welding (FSSW) is a solid-state welding process and one of the innovative methods to join specifically automotive components. Recently magnesium alloys are promising materials where combination of high strength and low density can be observed to improve vehicle performance and reduce emissions and fuel consumption in structural materials for automotive applications. A finite element model (FEM) established to understand the effect of axial force and rotational speed during the simulation in automotive applications. The FEM investigates the effect of axial force ranging from 1 kN to 8 kN and rotational speeds of 1000 rpm - 4000 rpm. The model analyses the heat flux and the temperature rise that leads defect formation after the process. 4.5 kN, 6 kN and 8 kN axial forces and 3000 rpm-4000 rpm rotational speeds are evaluated as the critical values in terms of defect and crack formation during the process under specified boundary conditions. Finally, several non-destructive inspection methods are suggested to secure structural integrity after the FSSW process to eliminate the harmful effects of surface and volumetric discontinuities.

Keywords

• Friction stir spot weld (FSSW)
• Finite element analysis (FEM)
• Magnesium alloy (AZ91)
• Axial force
• Rotational speed
• Nondestructive testing

Kaynakça

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