Welding in the food industry means that every seam must be durable and hygienic at the same time, otherwise there is a risk of contamination, corrosion and, in the worst case, product recalls. Successful welding technology is therefore particularly important in the beverage industry and food production, as it determines whether the surfaces remain clean and bacteria cannot find a starting point. Working cleanly here protects the products and safety in the company. Schnelldorfer Maschinenbau shows you what is important when welding in the food industry.
Why weld seams are critical in food production
Weld seams are literally the seams in systems and devices and as such are typical areas where something can get stuck if the workmanship is poor. Pores, cracks, joints, edges or unevenness: Residue sticks everywhere, moisture remains and bacteria can grow. This is why the highest hygiene requirements in the food industry have top priority: all surfaces and welded joints should always be as smooth and easy to clean as possible.
In practice, this is particularly evident in tank and pipeline construction: pipe interiors, transitions on tanks, nozzles, bottoms and dead spaces are the classic challenges here. The reason: many systems must be CIP-capable. CIP, short for Cleaning in Place, means that cleaning must work in the installed state - i.e. without dismantling the system. For CIP to work, however, it needs a suitable surface roughness and high seam quality without gaps. Weld seams that come into contact with liquids are therefore often ground flat and then cleanly reworked.
Norms and standards - What operators really need to comply with when welding
When welding in the food industry, the focus is on verifiable quality and compliance with food standards. Depending on the industry, market and application, there are different norms and standards, both nationally and internationally. It is important to note that all specifications are almost always aimed at a hygienic design and a clean surface in combination with a safe welded joint.
Overview of important standards and regulations
- EHEDG: European hygiene standard for the construction and processing of food-safe appliances and systems.
- DIN EN ISO 3834: Quality assurance for welding work. Important for reproducible production and controlled welding processes.
- DIN EN ISO 5817: Quality requirements and assessment levels for weld seams, such as permissible irregularities.
- IFS Food Standard: Overarching standard for the food chain. Relevant for audits, suppliers and processes.
- FDA / FSMA: In the USA, the FDA demands strict hygiene and safety requirements for food-contact surfaces via the Food Safety Modernization Act.
- USDA: Regulates standards in the USA depending on the segment, particularly in the meat and poultry sector. Often part of the gFramework.
- 3-A: Hygiene standards, strong in the dairy products sector, but mainly used in the food industry.
It quickly becomes clear why all these regulations count, as poor processing or unclear labeling can lead to contamination - and thus to complaints or recalls of entire product series. This is why points such as complete documentation, equally complete traceability, clearly defined welding parameters and traceable process control are now standard whenever seam quality and safety are required.
Material selection in the food industry - from stainless steel to aluminum
The choice of material has a direct influence on corrosion resistance, cleaning, durability and ultimately food quality. Stainless steel is often the first solution because the material scores points for good hygiene and strength and is also easy to work with. Nevertheless, it is worth looking at other materials.
Typical materials and their strengths
- Stainless steel 304: Frequently used, robust and easy to process. A proven basis in many systems.
- Stainless steel 316: Higher corrosion resistance, especially with acidic or salty media in food production.
- Duplex stainless steel: High strength with good corrosion resistance. Interesting for aggressive applications.
- Titanium: Lightweight and corrosion-resistant, suitable for special areas in industry.
- Aluminum, copper and special alloys: Possible, but challenging. What counts here is process knowledge, suitable methods and proper preparation.
Corrosion and the oxide layer are a particularly important issue for stainless steel, as the cleaning processes involving chemicals, temperature fluctuations and moisture attack the material as soon as the passive layer - i.e. the protective skin of the stainless steel - is weakened.
Hygiene and welding with various welding processes
TIG welding - The hygiene standard for clean weld seams
TIG welding is the preferred welding process in many food applications because it works in a particularly controlled manner. It is one of the gas-shielded welding processes and is a form of arc welding: an arc burns between the tungsten electrode and the workpiece, the metal melts and the filler metal is fed in separately. The shielding gas, usually argon, shields the welding area. And the result is smooth seams with few spatter and the highest quality - exactly what weld seams in the food industry need.
MIG, MAG and laser - when other processes still make sense
MIG and MAG are widely used in industry, especially when it comes to speed, efficiency and series production. In the food industry, however, the challenge lies in producing hygienic weld seams without spatter and unevenness. Although this is possible with these two welding processes, it requires extremely precise and clean welding technology with often more post-processing in the form of grinding or polishing.
Laser welding, on the other hand, is used when precision requirements are high. Due to the low heat input, the material deformation is often small - and this is exactly what helps with thin components, sensitive assemblies or narrow welding areas.
Orbital welding in pipeline construction - reproducible, documentable, hygienic
Orbital welding is an automated gas-shielded welding process that is particularly impressive in pipeline construction. A welding head moves mechanically around the pipe with constant welding parameters. This is a plus point for repeatability and consistently uniform seams. For this reason, welding technology is used both in food production and in the pharmaceutical industry. Wherever top seam quality, hygiene and reproducible processing are required, orbital welding shows its strengths.
Preparation and post-processing: How to make weld seams food-safe
Good welded joints can only be created with the right preparatory work. This includes Degreasing surfaces, cleaning metal, preparing joints cleanly, avoiding foreign particles and setting the welding parameters appropriately for the long term. This rapidly reduces the risk of irregularities and contamination - and improves the seam quality directly during the welding process.
After welding, thorough post-processing is essential, as grinding, polishing and final cleaning remove even the smallest imperfections and cracks. An advantage: electrochemical cleaning can remove tarnish and contamination without leaving any abrasive residue. The result is a surface that can be kept reliably clean throughout the entire production process.
Welding at the highest level - with the LINEARWELD series from Schnelldorfer Maschinenbau
Are you still looking for the right welding machine for seamless welded joints? With the LINEARWELD series, Schnelldorfer Maschinenbau offers you modular machines for all-round professional production. Our welding machines impress with PLC/HMI control, recipe management and high process reliability. You can use them to process workpiece lengths of up to 4,100 mm and material thicknesses of up to 15 mm - food-safe for steel, stainless steel, aluminum, copper, brass, titanium or special alloys. If you have any questions about the LINEARWELD devices, please do not hesitate to contact us - our team of experts will be happy to advise you.
Schnelldorfer Maschinenbau: How professional welding works in the food industry
If you want to weld in the food industry, you need a strong combination of genuine welding technology, suitable welding equipment and a process that ensures hygiene and quality in the long term. You will find all of this at Schnelldorfer Maschinenbau: Our devices score points with reproducible weld seams and all-round stable processing. For production that really meets your requirements.
See for yourself and contact us today - we look forward to hearing from you and your welding project!
Frequently asked questions (FAQ)
What is a food-compliant weld seam?
A food-compliant weld seam is smooth, non-porous and without cracks or joints to prevent bacteria or impurities from settling. It is designed in such a way that it is easy to clean and does not corrode easily. Standards and regulations specify exactly what a weld seam must be able to do in the food sector.
In which industry do you weld?
Welding is used in a number of industries, and the food and beverage industries are two of them. Welding is used in breweries, dairies, plant construction, container construction and pipeline construction. But pharmaceutical-related sectors also rely on hygienic welded joints.
Is welding with CO₂ food safe?
CO₂ is used as an active gas in MAG welding. Technically, this can work in certain applications, but hygienic surfaces are more demanding: spatter, heat discoloration and post-processing must be very cleanly controlled. This is why TIG welding or orbital welding are often preferred for food and beverages because they are easier to control.
Why is shaping necessary - especially for pipes?
During forming, the seam root is protected on the inside with forming gas. This prevents oxidation and thus tarnishing on the inside of the pipe. It also preserves the passive layer and improves corrosion resistance. This is particularly important in pipeline construction because the various media flow directly along the inner seam and cleanliness is the top priority.
What role does post-processing play?
Post-processing makes weld seams hygienic: grinding and polishing smooth out any unevenness and reduce edges where residue would otherwise collect.
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