Microstructural and Mechanical Characterization of Gas Tungsten Arc Welded 10 mm Thick AISI 316L Joints

Abstract

Austenitic stainless steels possess properties such as very good formability, good mechanical properties and high corrosion resistance even at low temperatures. As a result, it is the most produced and most widely used type among all stainless steels. However, there are many problems in welding of these steels. The most common of these problems is the decrease in corrosion resistance in the heat-affected zone as a result of the formation of chromium carbide. This study aims to produce defect-free joints in AISI 316L plates by gas tungsten arc welding method. For this purpose, 10 mm thick AISI 316L plates were welded in five passes using 2.4 mm diameter ER316L filler wire. In order to investigate and characterize the microstructural and mechanical properties of the welded plate, detailed optical microscopy studies and microhardness measurements were conducted as well as tensile testing. The effect of multi-pass welding on microstructural evolution and in turn on the mechanical behavior of the joint fabricated was also investigated. As a result of the study, no defects were observed in the weld region, and it was determined that the welded joint exhibited a weld performance of 104% and 58%, in terms of tensile strength and elongation, respectively. In addition, an increase in hardness was observed in the fusion zone and the heat affected zone.  

Keywords

• Austenitic stainless steel
• 316L
• Heat input
• Carbide participation
• Hot crack
• Welding performance

Gaz Tungsten Ark Kaynaklı 10 mm Kalınlığındaki AISI 316L Bağlantıların İçyapı ve Mekanik Karakterizasyonu

Abstract

Östenitik paslanmaz çelikler, düşük sıcaklıklarda bile çok iyi şekillendirilebilirlik, iyi mekanik özellikler ve yüksek korozyon direnci gibi özelliklere sahiptir. Bunun sonucu, tüm paslanmaz çelikler içerisinde en fazla üretilen ve kullanılan türdür. Ancak bu çeliklerin kaynağında birçok problem söz konusudur. Bunların başında, krom karbür oluşumu sonucu ısıdan etkilenmiş bölgede korozyon direncinin düşmesi gelmektedir. Bu çalışma, gaz tungsten ark kaynağı yöntemi ile AISI 316L levhalarda kaynak hatası içermeyen bağlantıların üretilmesini amaçlamaktadır. Bu amaca yönelik, 10 mm kalınlığında AISI 316L levhalar, 2,4 mm çapında ER316L dolgu teli kullanılarak beş pasoda kaynaklanmıştır. Elde edilen kaynaklı levhanın mikroyapısal ve mekanik özelliklerini araştırmak ve karakterize etmek için çekme testi yanında detaylı optik mikroskop çalışmaları ve mikro sertlik ölçümleri gerçekleştirilmiştir. Çok pasolu kaynağın mikroyapısal değişim üzerindeki etkisi ve dolayısıyla üretilen bağlantının mekanik davranışını nasıl etkilediği de araştırılmıştır. Yapılan çalışma sonucunda, kaynak bölgesinde herhangi bir hata gözlenmemiş olup, kaynaklı bağlantının çekme mukavemeti ve uzama açısından sırası ile %104 ve %58 lik bir kaynak performansı sergilediği tespit edilmiştir. Ayrıca, ergime bölgesinde ve ısıdan etkilenen bölgede sertlik artışı gözlemlenmiştir.

Keywords

• Östenitik paslanmaz çelik
• 316L
• Isı girdisi
• Karbür çökelmesi
• Sıcak çatlama
• Kaynak performansı

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