Experimental Study on Submerged Arc Strip Overlay Welding of Stainless Steel on Low Alloy Steel Surface

Literature Overview

This paper by Lin Qingguo, Wang Yunzhong, and Chen Zhixin from Guangzhou Heavy Machinery Works, published in Petrochemical Equipment (1993, Vol. 22, Issue 5, pp. 21–23), presents an experimental study on submerged arc strip overlay welding of stainless steel on low alloy steel surfaces. The study investigated the use of HJ107 and HJ107Nb fluxes in combination with 309L and 347L steel strips for overlay welding applications in heat exchangers and pressure vessels. The key finding was that obtaining high-quality ultra-low carbon welds requires low current, low travel speed, and low voltage, along with strict control of steel strip chemical composition.

Background and Motivation

Submerged arc strip welding (SAW strip) is a specialized welding process that uses flat steel strips instead of conventional wire electrodes. This process offers several advantages for overlay welding applications:

• High deposition rate: The flat strip geometry allows for higher current density and faster deposition.
• Good penetration control: The strip geometry provides consistent penetration depth.
• Low dilution potential: With proper parameter control, dilution can be minimized.
• Suitability for large components: The process is well-suited for large, flat surfaces typical of pressure vessel and heat exchanger applications.

The study focused on the overlay of austenitic stainless steel on low alloy steel substrates, which is a common requirement in petrochemical equipment manufacturing. The substrates are typically 2½Cr-1Mo (P91) or similar low alloy steels, while the overlay materials are 309L or 347L austenitic stainless steels.

Experimental Methodology

1. Materials Used