As a welder, sometimes tough just isn’t tough enough. There are times when you might need to increase the strength of a metal part to help minimize wear. How do you do that? Hardfacing. Hardfacing is a rather easy, yet effective method to prevent wear on your metal parts, helping them better fulfill their purpose. In this article we are going to discuss what hardfacing is and how you can use it to your advantage as a welder.
What Is Hardfacing?
Hardfacing, also referred to as hard surfacing, is a layer of wear-resistant and impact-resistant coating. This coating is beneficial when applied to a part as it increases its durability and service life. The process of hardfacing allows equipment to be exposed to extreme environments without nearly as many breakdowns meaning there will be less downtime. Hardfacing alloys come in an assortment of specifications that are carefully chosen to help increase the overall performance of the component that they are applied to. Hardfacing is often used to help build up surfaces that have started to wear down from day-to-day use, or as a proactive method to protect surfaces on new parts before they are put to use. Hardfacing can be achieved using a multitude of processes, both in the field and in a shop, which makes it more cost-effective and versatile. By using this method on new parts, you can extend the service life by up to 300%. By hardfacing worn parts, you are able to save as much as 75% compared to the cost to replace the part. This process does not require the use of specialized equipment and can be done using equipment found in most fabrication shops, garages, and repair stations.
What Parts Can Be Hardfaced?
Stainless steel, manganese steel, carbon steel, cast steel, cast iron, and an array of alloys can be hardfaced.
The most frequently hardfaced parts include those in the following industries:
- Agricultural Industry: Blades, chisels, cutters, furrowers, hoes, knives, plows, rippers, shears, shoes, shovels, spikes, sweeps, and teeth
- Construction Industry: Augers, buckets, bucket teeth, dozer blades, grousers, moldboards, and shears
- Mining Industry: Blades, buckets, bucket teeth, crusher rolls, hammers, pan conveyors, screw conveyors, sprockets, and trackpads
In these industries, there is no doubt that these tools are often used extensively in some of the harshest environments on the planet and can potentially only last several hours or a few days if they are not hardfaced. Taking the time to hardface these parts can extend their service life by weeks or months. Prevention is key when it comes to making parts last in the most demanding fields.
How is Hardfacing Applied?
There are quite a few methods for applying hardfacing, such as:
- Flux-cored arc welding (FCAW)
- Gas-metal arc welding (GMAW)
- Oxy-fuel welding (OFW)
- Plasma transfer arc (PTA)
- Shielded metal arc welding (SMAW)
- Submerged arc welding (SAW)
- Welding, resistance (stud) welding, and thermal spraying
Generally, the process is chosen based upon what is available, what type of coating is going to be applied, and where it will be applied.
Most Frequently Used Hardfacing Methods
- Shielded Metal Arc Welding: If equipment breaks down in a remote location, it wouldn’t seem practical to choose a submerged arc process to fix it, because the equipment is heavy and immobile. In this situation, shielded metal arc welding is the best option as it can be done swiftly and cost-effectively out in the field.When new equipment is fielded for the first time, automated methods that have an increased deposition rate are favored because of their repeatability and speed.
- Flux-Cored Arc Welding: Comparably, flux-cored arc welding is performed using affordable, readily available equipment in both a shop or out in the field. As a result, it is one of the most preferred hardfacing processes.
The three most frequently used flux-cored arc welding (and similar) processes are:
- Dot Pattern – For equipment that encounters larger aggregates, a dot pattern will likely be chosen. This process consists of dot-shaped welds which can be done in different sizes and distances to help reduce warping of the base material and to allow a dead bed to form with the size of the aggregate the equipment will come in contact with most of the time.
- Waffle Pattern – Done in a waffle or herringbone pattern, you are able to crisscross the welds to create squares. Smaller aggregates like dirt, sand, and gravel can create a dead bed that essentially serves as an additional layer of protection.
- Stringer – The stringer pattern is done with stringer beads and are run parallel and spaced at various distances ranging from ¼’ to 1.5’. When aggregates are larger in size, the beads run parallel to the material flow.
If you are thinking about hardfacing a piece of equipment, there are plenty of options to get the result you are hoping for. If you aren’t sure what process, shielding gas, or filler will be best, reach out to your welding supplier for help.
Hardfacing Isn’t Hard
To close this up, it is important to know that hardfacing is a less challenging way to effectively reduce the wear on any of your metal parts. Now that you know more about it and its processes, you can feel more comfortable when choosing to hardface your parts for extended use.
