In many medium to heavy industrial segments – agriculture, oil and gas, steel, mining, cement, recycling, power generation and others – metal wear is an ever-present challenge. Whether from abrasion, impact, corrosion, heat or a combination of these factors, metal-to-earth and metal-to-metal contact leads to component deformation and eventual reduction of equipment or system efficiency, requiring repair or replacement.
Production-stealing downtime and the ancillary resources required to address wear damage only exacerbate the costly repair and maintenance challenges for business owners and those tasked with managing these activities. It is these cumulative factors that led Stoody, an ESAB brand, to develop a family of iron-based low-alloy, martensitic hardfacing wire electrodes that deliver superior wear resistance with all-position application capabilities.
No longer restricted by consumables formulated to run only in the flat position, these wire electrodes give welders the freedom to choose whether to apply hardfacing alloys in situ or in a shop environment. These all-position wires allow work to be performed faster as they can be applied without repositioning the component.
All-position flexibility can shave significant time from the welding process as the welder can simply move from flat to vertical sections of a component without having to stop for repositioning (see Figure 1). And because repositioning is no longer necessary, mobile welding systems can be employed on location where the component or equipment is in service.
This can further reduce costs by eliminating longer periods of downtime and the resources traditionally needed to remove components, transport them to a facility housing the necessary repositioning equipment, and subsequently to return and reinstall the components post-welding.
Working closely with customers within the mining segment initially, Stoody envisioned a family of cost-effective iron-based wire electrodes that could be utilized in situ to rebuild damaged components and to overlay or clad components to limit or retard wear, thereby extending the serviceable life of the components. Three all-position wires were developed in 0.045-in. (1.2-mm) and 1/16-in. (1.6-mm) diameters that can be run using constant voltage machines with the appropriate shielding gas – typically a 75 to 80 percent Ar/CO2 mix. Among these is Stoody Build-Up AP-G, a gas-shielded, flux-cored, all-position general-purpose wire recommended for the rebuilding of worn or broken mild or low-alloy steel components and as an underbase for subsequent hardfacing overlays.
This alloy produces a low-alloy deposit exhibiting excellent compressive strength and resistance to plastic deformation, yet can be machined in the as-welded condition using carbon tools. The alloy operates in a smooth semi-spray transfer allowing for high deposition in out-of-position applications.
Deposits can be applied crack-free in multiple layers and have been used to return hammers, shovel pads, rolls and other components to optimal dimensions. With a two-layer hardness of 24-27 HRC, the build-up application is routinely followed up with another hardfacing alloy for improved wear resistance.
User profile: Open pit mining
A large mining operation in a remote section of North Dakota employed very large excavators and earth movers in an open pit setting where metal-to-earth wear, including extreme abrasion and impact, often contributed to deformation and damage. The sheer size of damaged components and the distance from the job site to suitable maintenance facilities with repositioning equipment complicated the maintenance and repair effort.
Problem: One of the large excavators was showing advanced wear on the backside of the bucket due to severe abrasion and moderate impact. Miles from the maintenance facility, the team tasked with repairing the bucket hoped to find a build-up solution that could be applied onsite to bring the bucket back to spec.
Solution: Repairs to the backside of the bucket were successfully completed using Stoody Build-Up AP-G in situ, greatly reducing lost production time. Having been restored to optimal dimensions, the bucket was then hardfaced with an overlay alloy deposit for improved wear resistance.
Flexible application, solid performance
The brand’s all-position product portfolio includes two hardfacing overlay alloys, Stoody 964 AP-G and Stoody 965 AP-G. Both iron-based martensitic formulations are recommended for impact and abrasion resistance in metal-to-metal and metal-to-earth applications and are intended for overlays on used or new components of carbon, low-alloy or manganese steel construction.
With a smooth semi-spray transfer, Stoody 965 AP-G produces deposits with a two-layer hardness of 57-62 HRC. The out-of-position weldability and good balance of impact and abrasion resistance has made the alloy increasingly popular as an overlay in numerous industrial segments internationally with applications found on tillage tools, dredge parts, shredding knives, bucket lips and teeth, and in other numerous applications where components are exposed to a combination of wear factors. Deposits are forgeable but not readily machinable, with layers typically limited to two, with a three-layer maximum.
Stoody 964 AP-G offers the highest relative wear resistance in an all-position hardfacing wire (see Figure 2). A specially formulated martensitic iron-based alloy, it produces a uniform distribution of small primary carbides in the matrix. The small carbides provide greatly improved wear resistance over martensitic steel, many tool steels and some conventional chromium carbide alloys (see Figure 3).
Possessing excellent resistance to impact and plastic deformation, Stoody 964 AP-G deposits are crack-free on carbon, 300 stainless and manganese steels. With other base metals, preheating and post-heat treatments are recommended. The alloy has a hardness of 58-64 HRC and is recommended for components where cross-checking is undesirable.
Like Stoody 965 AP-G, the alloy can be applied to carbon and low-alloy steels and is commonly used by manufacturers seeking to protect various types of blades, screws, auger flights, tamper feet, tillage tools, dredge parts and bucket lips. Deposits are limited to two maximum.
User Profile: Municipal wastewater management
An OEM developing and manufacturing systems for industrial and municipal wastewater treatment in New Jersey needed a wear-resistant cladding for vessels designed to heat and compress waste for removal at the end of metropolitan sewer systems. In this application, the vessels were regularly exposed to severe abrasion, corrosion and heat.
Problem: Realizing their wastewater vessels required constant repair despite previous cladding with an alloy from Turkey, the manufacturer contacted Stoody for suggestions on alloys that could better withstand the wear. Adding greater complexity, the repairs had to be made in situ inside the vessels and had to be suitable for welding over existing hardfacing deposits of varying chemistries.
Solution: Stoody conducted numerous tests in support of the manufacturer to ensure the right hardfacing alloy would be identified for the job. The manufacturer chose Stoody 965 AP-G and was able to improve the serviceable life of their vessels due to the more wear-resistant characteristics of the deposit. In addition to benefiting from the reduced frequency of repairs, the manufacturer was also able to get consistent out-of-position welds throughout the vessels, eliminating issues encountered with alloys never designed for all-position applications.
User Profile: Heavy industrial equipment
An OEM producing heaving mining equipment in Balikpapon, Indonesia, faced an application challenge. As part of its manufacturing process, large sections of protective wear plating are welded to the insides of enormous earth-moving buckets to extend serviceable life.
Problem: The structural welds holding the wear plates to the base metal are commonly made using a conventional welding alloy never designed to withstand the rigors of extreme abrasion and wear. These structural welds represented the weak link in the OEM’s product.
Solution: The OEM began applying Stoody 964 AP-G as a protective overlay or capping deposit over the structural welds to provide optimal protection (see Figure 4). The OEM not only benefited from the deposit’s wear-resistant characteristics, but also from the flexibility to weld out-of-position, which eliminated the need for repositioning its multi-ton bucket components.
Stoody, an ESAB brand