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Bonding stainless steel instead of welding
In modern engineering and manufacturing, choosing an efficient and durable joining method is key to product quality and reliability. INOX stainless steel, with its corrosion resistance and wide applicability, is used across industry, construction and medical environments. While welding remains a traditional joining method, adhesive bonding is increasingly considered as an alternative. In this article we compare welding and bonding in a practical, process-oriented way: what to consider and when bonding can be a realistic option.
Key takeaways
✅ Bonding can be an alternative to welding when aesthetics, reduced thermal distortion and joining dissimilar materials matter
✅ Joint performance depends heavily on surface preparation (abrading + degreasing) and correct adhesive selection
✅ Welding requires qualified welders and specialized equipment; bonding requires process discipline and HSE, but training can be easier to scale
Stainless steel – properties and typical use
INOX stainless steel (from inoxydable – “non-oxidizing”) refers to a group of steels with specific physicochemical properties, resistant to corrosion caused by atmospheric exposure (gas corrosion), diluted acids and alkaline solutions (corrosion in liquids).
Where and why is stainless steel used?
The main reasons stainless steel is commonly used include:
- corrosion resistance
- use in aggressive environments
- high-temperature resistance
- bright, polished appearance
Stainless steel is often used for tanks, cisterns, pools, industrial installations, turbine blades, industrial fittings, surgical tools, marine hardware, steel structures, decorative elements, elevators, cold rooms, air-conditioning units, heat-resistant furnaces and railings. Additionally, HACCP requirements mean that items in contact with food should be made of stainless steel (e.g., slaughterhouses, food processing plants and catering facilities).
Traditional joining methods for stainless steel include bolting (easy assembly/disassembly, but potential crevice corrosion), soft/hard soldering, mechanical crimping and welding. A modern technology that is gaining attention is adhesive bonding.
The purpose of this text is to compare welding with bonding as an alternative joining technology for stainless steel.
Welding methods for stainless steel
A table shown next to this section presents stainless steel grades and their weldability. This is important information before welding. In bonding, such tables are not typically used—if the substrate cannot be identified, you can perform a surface energy test or a bonding test to evaluate how a given grade behaves.
TIG welding (GTAW)
TIG is one of the basic processes used for producing structures, especially from high-alloy steels. It can be used across a wide thickness range—from fractions of a millimetre up to very large thicknesses. It can be performed manually, semi-automatically or automatically, making it useful in workshop and on-site conditions, in all welding positions. A drawback is relatively low penetration depth and low productivity.
Source: Andrzej Klimpel, “Spawanie, zgrzewanie i cięcie metali”, WNT, 1999.
Source: Andrzej Klimpel, “Spawanie, zgrzewanie i cięcie metali”, WNT, 1999.
PAW (Plasma Arc Welding)
PAW uses a non-consumable tungsten electrode in an inert gas shield. Plasma is an ionized gas, requiring high temperature. PAW can be performed with a non-consumable electrode (plasma GTA) or a consumable electrode (plasma GMA). TIG arc temperatures are around 6000 °C; in plasma welding the arc is constricted by a water-cooled nozzle, increasing temperature up to about 20000 °C. This technique can produce a weld in one pass for material thicknesses from 3 to 15 mm with favorable penetration profile and minimal distortion. Welding speeds can be 40–80% higher than TIG.
GMAW (MIG / MAG)
In GMAW, the arc is shielded by externally supplied gas and a continuously fed consumable wire electrode is used. Heat is generated by an arc between the wire and the workpiece. Unlike GTAW/PAW, the electrode is consumed and the arc burns between the wire and the workpiece within the shielding gas.
FCAW (Flux Cored Arc Welding)
FCAW is a variation of GMAW using flux-cored wire. The wire consists of a metal sheath (stainless steel) filled with flux. The flux role is similar to electrode coating in SMAW.
Source: Andrzej Klimpel, “Spawanie, zgrzewanie i cięcie metali”, WNT, 1999.
SMAW (MMA)
SMAW is shielded metal arc welding where shielding is generated by electrode coating decomposition. It is often used for less critical repairs on corrosion-resistant steels. Equipment cost is low, but welding is slower than GMAW/FCAW and thin parts may burn through. Also known as MMA (manual metal arc).
Other welding methods
- LBW (Laser Beam Welding)
- EBW (Electron Beam Welding)
The most common methods you typically encounter are MMA/TIG and MIG/MAG.
Limitations of welding stainless steel
Welding offers many process options, but also comes with constraints.
- Need for qualified welders (often a market shortage).
- Aesthetic defects created during welding.
- Need for specialized equipment.
- MIG/MAG: limited pool control, relatively high current, risk of spatter.
- MMA: spatter, porosity, lower productivity.
- FCAW: high cost of flux-cored wire.
- TIG: relatively shallow penetration and low productivity.
- High electrical energy consumption.
Bonding stainless steel
When joining stainless steel to itself or to plastics/composites, adhesive bonding can be used as an alternative to traditional joining methods. Modern adhesives available on the market can provide structural joints while maintaining high joint aesthetics.
For a deeper overview of joint design and key process factors, see: How to design an adhesive joint (advantages, limitations and joint classification).
If the topic caught your attention – watch the videos
📌 If you want a step-by-step process (surface prep, application, workflow) – watch the first video.
📌 If you’re interested in tests and real-life joint behaviour – watch the second video.
2K adhesives for steel – product selection
If you’re looking for structural bonding solutions for metal applications (including 2K adhesives), see the category:
➡️ Adhesives for metal – including 2K options for steel
[product id="2907,3643,1969,3522"]
Like any technology, bonding also has limitations. One of them is HSE requirements. For one-component adhesives, a drawback can be curing time and the need for a staging area while the joint cures. The key is selecting the right adhesive and having personnel trained to apply the technology.
Surface preparation is typically the first step: abrading and degreasing. You need a tool for abrading (e.g., sander, abrasive paper) and—most importantly—a suitable degreasing agent. For plastics, acetone may degrade the surface. In practice, extraction gasoline may leave a film that can reduce adhesion. Dedicated surface preparation products are usually the safest option. Various alcohols are commonly used; a widely used universal option is isopropyl alcohol (IPA).
An investment may include a dispensing gun. For advanced 2K systems and pneumatic guns, the one-time cost can be around 3000 PLN net. For smaller packs or manual guns, equipment cost is typically around 150–900 PLN net, depending on the device type.
A benefit of bonding technology can be relatively fast handling strength (the part can be moved after about 25 minutes). The instructional videos also show strength testing of the joints. In many cases, material-level strength can be achieved without compromising the aesthetics of the bonded parts, which matters for visually demanding applications.
Summary
- INOX stainless steel is widely used thanks to corrosion resistance, high-temperature resistance and suitability for aggressive environments.
- Welding (TIG, PAW, GMAW, FCAW, SMAW) has process and organizational limitations.
- Bonding can provide aesthetic structural joints, but requires correct adhesive selection and a repeatable process.
- Bonding limitations include HSE requirements and curing time (especially for 1K systems), as well as the need for consistent surface preparation.
- Bonding technologies evolve rapidly and should be considered alongside traditional joining methods already at the design stage.
FAQ – bonding stainless steel
When does bonding have an advantage over welding?
When aesthetics, reduced thermal impact and distortion, and joining dissimilar materials (plastics/composites) are important.
What is critical for bonding stainless steel?
Repeatable surface preparation (abrading + degreasing), correct adhesive selection and control of process conditions.
Is acetone or extraction gasoline always suitable for degreasing?
Not always. Acetone may degrade some plastics, and extraction gasoline may leave a film that reduces adhesion. Dedicated surface preparation products and proven cleaning procedures are typically recommended.
How can curing time be managed in production?
By selecting an appropriate bonding technology (e.g., 2K), organizing staging areas and matching dispensing equipment to throughput needs.
Author
Marcin Filipczyk – long-time specialist in adhesive bonding.
Sources
Andrzej Klimpel: Spawanie, zgrzewanie i cięcie metali. WNT, 1999.
Górka, J., Stano, S. “Microstructure and properties of hybrid laser arc welded joints…”, Metals 8.2 (2018).
Yan, J., Gao, M., Zeng, X. “Study on microstructure and mechanical properties…”, Optics and Lasers in Engineering 48.4 (2010): 512–517.
Arnold, R. W., Combe, E. C., Warford Jr., J. H. “Bonding of stainless steel brackets…”, AJODO 122.3 (2002): 274–276.
