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Journal of Mechanical Science and Technology 25 (9) (2011) 2171~2177
www.springerlink.com/content/1738'494x
DOI 10.1007/s12206'011'0705'4
Effect of constraint on fracture behavior of welded 17mn4 and aisi304 steels
Bahadir Uyulgan1, Hakan Cetinel2,* and Tevfik Aksoy1
1Department of Metallurgical and Materials Engineering, Dokuz Eylul University, Buca Izmir, Turkey
2Department of Mechanical Engineering, Celal Bayar University, Muradiye Manisa, Turkey
(Manuscript Received December 30, 2010; Revised May 10, 2011; Accepted May 11, 2011)
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Abstract
In this study, 17Mn4 (P295GH) pressure vessels steel and AISI304 stainless steel were welded with ER309L austenitic consumable. In experimental part of the study, tensile tests were conducted on welded plates and variation of hardness values along specimen was meas' ured. J'integral fracture toughness values were investigated for different crack locations. In order to determine the regions where plastic deformation did not take place due to constraint, uni'axial tensile test was performed on welded tensile specimen after attaching strain gauges. In numerical part of the study, finite element (FE) analyses were conducted by fixing 2'D models precracked on different loca' tions by using ANSYS software. In these models, stress triaxiality and plastic deformation characteristics around crack tip were deter' mined for each crack locations after stress strain analyses. The limitation on the extension of plastic deformation at diffusion line causes extra increase in stress triaxiality at crack tip.
Keywords: Weld; J'integral; Constraint; AISI304; Mismatch; P295GH; Fracture toughness
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1. Introduction
17Mn4 (P295GH) is the carbon'manganese steel widely used for production of pressure vessels, steam boilers, pipe lines etc., which work under high temperature conditions, according to BS EN 10028'2. AWS ER309L is the austenitic stainless steel rod used for tungsten inert gas (TIG) welding of stainless steel and low alloy steels. These rods can be used in weldments exposed up to 300C operating temperatures [1]. Welding of AISI 304 (X5CrNi18'10) austenitic stainless steel materials with low alloy steels or plain steels is a very frequent situation.
Welded joints are more sensitive parts of a structure with regard to crack growth and failure, because of the inherent characteristics of weldments. The fracture property analysis of a welded joint is a main part in any structure integrity assess' ment [2]. Since the mechanical heterogeneity in the welded joint affects the flow and fracture, as the material researchers have...