Professional welders know the potential dangers welding poses for their health and safety. Without the proper personal protective equipment (PPE), they risk permanent damage to their eyes, burns, electrical shock, the respiratory risk from fumes, and the hazards associated with compressed and liquefied gases.
Welders can mitigate or avoid these hazards by applying the proper safety practices, wearing the recommended clothing, and employing any available safety gear and equipment. Because welding is considered among the most dangerous occupations, there is little debate surrounding the importance of health and safety issues as it pertains to the people who work in the profession.
However, another issue is in play here, focusing on the environmental impact of welding and what might be done to alleviate the ecological effect it generates. Can welders use more environmental-friendly practices to reduce welding’s impact? Or is an attitude of “it-is-what-it-is” all we can offer for now? Let’s take a look:
Is welding bad for the environment?
The traditional first step in problem-solving is determining if a problem exists. In other words, is welding detrimental to the environment? And the answer is that welding can cause considerable air pollution, threatening human health and the Earth's ecosystems. According to a World Health Organization (WHO) report, air pollution is associated with around 7 million premature deaths annually.
Because it is a critical and popular operation in many industries, welding sends out numerous fumes and gases that become air pollutants. The high temperatures during the welding process vaporize various substances in the arc that condense and oxidize in contact with the air, forming fumes. Factors such as surface coatings, filler metal, and welding type determine the kind and amount of generated particles and gases.
As for gases, the most widespread emissions during welding are carbon monoxide, ozone, phosphine, and nitrous gases. Gases are generated from high temperature and ultraviolet (UV) radiation from the arc. Like fumes, several factors can affect the emission during welding. For instance, ozone forms depending on the process type, material, and shielding gases. Welding gases are also generated when surface coatings or contaminants meet hot surfaces or UV radiation.
Welding Techniques That Reduce Fumes
The amount of welding fumes depends on the welding method. Although TIG does produce significant amounts of ozone and nitrous oxide—both of which can irritate—it has the least fume. MIG and MAG typically make much more fume, but MMA (stick) welding and flux-cored tend to produce the most. Resistance welding generally produces fewer fumes than manual arc welding processes.
Higher currents and long duty cycles generate more fumes and affect weld quality. By optimizing your shielding gas, you can have the best production speed and the lowest fume emissions. All the major welding gas suppliers offer shielding gases that allow welders to weld faster, with higher quality finishes and fewer fumes. Tell your gas supplier what your application will be, and let them recommend the shield gas mix that will optimize it.
How can welding be more environment-friendly?
In the past, many weld and fabrication shops were inclined to choose a welding process based on the welding equipment’s availability, the weld quality, the process’s efficiency, and costs. However, recently, more and more businesses are focusing on their environmental impact and how they can improve it.
Here are 8 steps you can take to institute environment-friendly welding practices:
1. Adjust the welder settings
The fumes released during welding are directly affected by the welder settings. When welding operators use high voltage and amperage, it can cause an increase in the levels of welding fumes. Minimizing emissions might be as easy as choosing the lowest amperage needed instead of starting with high power and heat. Operators can still ensure enough penetration for an effective weld joint.
2. Choose the shielding gas carefully
A 100% CO2 shielding gas increases the arc’s heat, causing more vaporization and fumes. Instead, opt for an argon gas blend.
3. Clean the metal before welding
As mentioned, welding fumes are also caused by contaminants or coatings on the metal surface. When these impurities are heated or in contact with UV radiation, they produce new welding fumes. Examples of contaminants include residue from solvents and paint, oil and rust inhibitors, and zinc on galvanized steel. Use a stripping product to remove them and any other residue before welding to minimize welding fumes.
4. Use the welding technique producing fewer fumes
MIG welding (GMAW) and TIG welding (GTAW) are the two most common methods. TIG requires more skill to produce its intricate welds, and MIG is easier to learn, making it a popular choice even though the weld quality isn’t as high. As for the environment, TIG welding produces fewer fumes than MIG welding, including lower ozone and nitrogen oxides, resulting in TIG being more environmentally friendly.
5. Choose an alternate welding method
If TIG welding is not viable, you could consider two other methods to protect the environment: friction welding and diffusive welding.
Friction welding involves the use of friction force. The friction between a rotating tool and the workpiece generates enough heat to join the metals. Friction welding is an environment-friendly technique that eliminates the need for flux and allows for generating the motor using only the required energy. As a result, this technique reduces the carbon footprint, leading to cleaner air.
Diffusive welding combines pressure and heat to produce high-quality joints, removing the need for flux and making it an environmentally friendly and sustainable option for welding. In addition to its benefit as a green welding option, the diffusive welding technique offers two other attractive advantages: it’s a relatively simple approach and yields impressive results. Although it’s an environmental-friendly method, diffusive welding might not be feasible since it’s a long process that may be costly for large-scale welding.
6. Consider vacuum soldering
Traditional soldering requires flux, which prepares the metal to receive the solder, preventing oxidation at the joint. Unfortunately, the flux achieving these effects poses specific threats to the environment. Corrosive agents must be cleaned from the finished solder point, and those solvents could be toxic to human health and cause chemical changes that release unhealthy fumes into the air.
Vacuum soldering resolves the issue with hydrogen instead of flux. Reportedly, hydrogen provides the same functions as a flux in stabilizing and securing a join. By reducing the pressure on the liquid solder, a precise temperature is maintained as the solder solidifies, creating an excellent join. Remarkably, the hydrogen does all the post-solder “cleanup work” without the toxicity caused by flux.
7. Recycle welding waste properly
Recycling is one of the original pieces of advice on environmental conservation. Instead of disposing of the unusable scraps, you hold on to them, allowing them to be used in other projects (and saving money for your company). Another consideration is to take them to a professional recycler to ensure they are correctly handled.
8. Choose environment-friendly metals for your next project
Every business is now expected to be more environmentally responsible. So, if you're planning a welding project, you should consider using metals contributing to environmental conservation. Here are three to start:
Aluminum: Aluminum is one of the most recycled metals, typically producing the same high-quality product after recycling. It’s popular because it's durable, lightweight, and versatile and works well in many welding projects. Once you have completed the project, aluminum needs very little maintenance and has high sustainability and environmentally friendly traits.
Stainless steel: Stainless steel is another sustainable metal that retains its qualities through countless recycling. This quality differentiates stainless from other materials that lose their quality and performance with each recycling.
Scrap metal: Although it might be appropriate for a large welding project, scrap metal is an ideal eco-friendly material. Merely find the nearest scrap yard and order the material. Scrap prices are typically much lower than new metals.
Many business practices can hurt the environment, and welding is merely one of them. Fortunately, there are ways that professional welders and welding businesses can take steps to reduce their consequences.
From adjusting welder settings to picking the optimum shielding gas to choose the most environment-friendly welding technique, everyone in the welding community can play an essential part in reducing pollution.
With over 300,000 welders employed in the country and many more hobby welders, there are plenty of opportunities to perform more environmentally friendly welding processes.