The question asks us to identify the welding process that is different from the others listed. We need to understand the characteristics of each mentioned welding process to find the odd one out.

Welding Process Overview

Let's look at the different welding processes provided in the options:

• Stick welding: This is a common term for Shielded Metal Arc Welding (SMAW). It uses a consumable electrode covered in flux to lay the weld. The flux coating protects the weld pool from contamination.
• Shielding metal arc welding: This is the formal name for the process commonly known as stick welding or SMAW. It utilizes a consumable electrode coated with flux.
• Manual metal arc welding: This is another term often used interchangeably with SMAW or stick welding, emphasizing that the process is typically done manually.
• Submerged arc welding: This is an arc welding process where the arc is "submerged" under a blanket of granular flux. It uses a continuously fed consumable wire electrode.

Comparing the Welding Processes

To find the odd one out, let's compare these processes based on key features:

Similarities in Stick, SMAW, and MMAW

Stick welding, Shielded Metal Arc Welding (SMAW), and Manual Metal Arc Welding (MMAW) all refer to the same fundamental welding process. Key characteristics include:

• Electrode: Uses a consumable electrode coated with flux.
• Shielding: The flux coating on the electrode decomposes when heated by the arc, creating a shielding gas to protect the weld pool and forming a slag layer that also protects the cooling weld.
• Operation: Typically a manual process, requiring the welder to manually control the electrode angle, travel speed, and arc length.
• Versatility: Can be used in various positions (flat, horizontal, vertical, overhead).

Characteristics of Submerged Arc Welding (SAW)

Submerged Arc Welding (SAW) differs significantly from the SMAW family of processes:

• Electrode: Uses a bare, continuous wire electrode.
• Shielding: Relies on a separate, granular flux that is poured onto the weld area before welding begins. This flux covers the arc, preventing atmospheric contamination and forming a protective slag.
• Operation: Primarily an automatic or semi-automatic process, often used for long, straight welds where the wire feed and flux delivery are automated.
• Application: Best suited for flat or horizontal welding positions due to the granular flux.
• Deposition Rate: Generally offers higher deposition rates and speeds compared to SMAW.

Identifying the Odd One Out

Based on the comparison, Stick welding, Shielded Metal Arc Welding, and Manual Metal Arc Welding are essentially different names for the same manual arc welding process using a flux-coated electrode. Submerged Arc Welding, however, uses a different method for shielding (granular flux blanket) and electrode feeding (continuous bare wire), and is typically automated.

Therefore, Submerged arc welding is the odd one out because it fundamentally differs in its shielding mechanism, electrode type, and usual mode of operation compared to the other three options, which describe the same process (SMAW/MMAW).