Requirements for qualification of GTAW manual welding of butt joints between clad tubes according to ASME BPVC Section IX edition 2025

Abstract

Cladded boiler components are used to make boilers that use waste as fuel. These boilers are known as waste to energy boilers. Andritz TEP is one of the largest producers of these types of boilers in Europe. In his 20 years of experience in the production of these types of boilers, he has produced more than 50 of them. The most critical places of these boilers are the connection points, the butt joints of the clad tubes. As the boiler is delivered to Canada, the qualification of the welding process is performed according to the requirements of ASME BPVC Section IX, Edition 2025. During the qualification, it is necessary to define the qualification method, essential and non-essential welding variables for GTAW welding process, the methods and scope of examinations including the acceptance criteria according to the requirements of ASME BPVC Section I and IX, Edition 2025. In addition to the standard qualification requirements, it is necessary to examine the chemical composition of the corrosion resistant overlay metal, determine the minimum thickness of the corrosion-resistant layer. The main requirement for the chemical composition is based on the alloy used for the corrosion resistant overlay, ERNiCrMo-3, and the maximum iron content. The maximum acceptable iron content for manual welding is 7% Fe.