Open Arc vs. Submerged Arc Welding for CCO Wear Plate

The welding process is a fundamental part of manufacturing CCO wear plate. It determines how the hardfacing alloy is deposited onto the steel base plate and affects important factors such as heat input, dilution, deposition conditions and the resulting overlay microstructure.

Two established deposition processes are commonly used for chromium carbide overlay wear plate: Open Arc Welding and Submerged Arc Welding (SAW).

Although both processes can be used to produce chromium carbide hardfacing overlays, they are different welding processes rather than different CCO grades. Understanding how they work helps explain differences in manufacturing methods, surface appearance and process control.

Open Arc Welding

Open Arc Welding refers to hardfacing in which the welding arc is exposed during deposition rather than being covered by a layer of granular welding flux.

In CCO wear plate manufacturing, flux-cored welding wire can be used to deposit a chromium-carbide-containing alloy onto a steel base plate. The welding wire contains the alloying elements required to form the hardfacing layer, while the welding parameters control the melting and deposition process.

As the deposited alloy cools and solidifies, chromium-rich carbides can form within a metallic matrix. In typical Fe-Cr-C hardfacing systems, Cr₇C₃-type carbides are an important hard phase associated with abrasion resistance.

The final overlay structure is influenced by several variables, including:

Hardfacing alloy chemistry

Carbon and chromium content

Welding current and voltage

Travel speed

Heat input

Dilution

Cooling and solidification conditions

Overlay thickness

Therefore, the welding process should not be evaluated separately from the hardfacing alloy and welding procedure.

Special Patterns: Grid and Wave Welding

A notable feature of open arc hardfacing is the ability to control the welding path and create different bead arrangements on the working surface.

Two common examples are grid welding and wave welding.

A grid welding pattern is created by depositing intersecting or crossing weld beads across the plate surface.

A wave welding pattern is produced through a curved or oscillating welding path, creating continuous wave-shaped beads.

Submerged Arc Welding

Submerged Arc Welding (SAW) uses a fundamentally different welding environment.

During SAW, the welding arc and molten weld pool are covered by a layer of granular welding flux. The arc operates beneath this flux layer rather than being directly exposed.

SAW is well suited to mechanized and automated deposition. This makes it possible to maintain controlled welding conditions over large areas of the steel base plate.

However, the use of SAW does not by itself define the wear performance of the finished plate. The deposited alloy and resulting microstructure remain fundamental to the characteristics of the CCO overlay.

Open Arc Welding vs. Submerged Arc Welding

The main difference between the two processes is the environment in which the arc and molten metal are deposited.

The table describes manufacturing differences, not a ranking of product grades.

A CCO wear plate produced by open arc welding is not automatically a lower-grade product than one produced by SAW. Likewise, SAW does not automatically make a CCO overlay more wear-resistant.

The performance of the finished overlay depends on the complete deposition system.

How the Welding Process Influences the CCO Overlay

Although the welding process does not determine a CCO grade by itself, it has an important influence on how the hardfacing alloy is deposited and solidified.

Dilution

During hardfacing, a portion of the steel base plate melts and mixes with the deposited alloy. This is known as dilution.

Because the base plate and hardfacing alloy have different chemical compositions, dilution changes the effective composition of the deposited layer.

This is important for CCO manufacturing because the hardfacing alloy is designed to produce a specific carbide-containing structure. Excessive or poorly controlled dilution can alter the resulting chemistry and microstructure.

Both open arc welding and SAW therefore require appropriate welding procedures and process control.

Heat Input and Solidification

The thermal cycle during welding affects how the molten hardfacing alloy solidifies.

Welding current, voltage, travel speed, deposition rate and other parameters influence heat input and cooling conditions. These factors can affect the formation and distribution of chromium-rich carbides and the surrounding metallic matrix.

The objective is not simply to maximize or minimize heat input. The welding procedure needs to provide a stable deposition process and the required overlay characteristics.

Carbide and Matrix Structure

A CCO overlay consists of a hard carbide phase within a metallic matrix.

In Fe-Cr-C hardfacing systems, chromium-rich carbides such as Cr₇C₃-type phases can form during solidification. Their morphology, distribution and relationship with the matrix contribute to the abrasion behavior of the overlay.

This is also why hardness alone does not fully describe the performance of a chromium carbide overlay wear plate.

Two overlays may have similar HRC values but differences in carbide morphology, distribution or matrix structure.

Overlay Thickness

The welding process must also provide a consistent overlay thickness according to the product specification.

For example, a designation such as 6+6 mm generally refers to a 6 mm steel base plate and a nominal 6 mm hardfacing overlay.

The required overlay thickness is determined by the product design and expected wear conditions. The welding process needs to deposit sufficient material while maintaining the required bonding and dimensional characteristics.

Is One Welding Process Better Than the Other?

There is no technically sound basis for treating Open Arc Welding and SAW as a simple “better versus worse” comparison.

They are different processes with different welding environments and operating characteristics.

The relevant question in manufacturing is whether the selected process can consistently produce the required hardfacing overlay with the specified alloy chemistry, thickness, bonding quality and microstructure.

In other words:

Welding Process → Deposition Conditions → Overlay Microstructure → Final CCO Properties

The welding process is one part of this chain, not the sole determinant of the final wear performance.