Doctoral Dissertations

Date of Award

8-2004

Degree Type

Dissertation

Degree Name

Doctor of Philosophy

Major

Materials Science and Engineering

Major Professor

Carl D. Lundin

Committee Members

Raymond A. Buchanan, Peter K. Liaw, David C. Joy

Abstract

It is generally recognized that hot cracking or microfissuring is one of the main concerns in austenitic stainless steel welding. Microfissures formation can be attributed to the presence of liquid film along the grain boundaries near the bulk solidus temperature under a sufficient strain to rupture the liquid film. Microfissures can be controlled to a certain extent by attention to consumable composition, purity, and welding technique, but they cannot be uniquely eradiated in real weld application. The occurrence of the microfissures can be the cause of weld rejection and may induce property degradation of the weld metal. With the increase of utilization of heavy section of austenitic stainless steel, the microfissures have been raised concern in the application of industries. In this study, eight kinds of commercial and modified electrodes provided by Lincoln Electric Company, ESAB and Hobart were used to produce fissure-containing and fissure-free welded coupons for extracting the samples for this investigation. The modified electrodes, E308L, E316L, E308H and E316H, are those electrodes which Ferrite Numbers are around zero to produce microfissures for the investigation. Except these electrodes, some of the pads from the earlier projects entitled "Fissure Bend Test" and "Weld Metal Fissuring Tendency of Kro-Kay 316-15" were also used because of the pads with the different microfissuring levels. All of the commercial and modified electrodes used in this research fall within the AWS A5.4 specification.

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