Metal welding: reliable structural welding services

What is metal welding and why is it needed?

Metal welding is a process in which two or more metal parts are joined using thermal input (sometimes with filler metal) to create a strong, continuous joint. This process is often essential for business clients who manufacture structures, frames, engineering systems, or industrial solutions.

The welding principle – heat input and the joint

Heat input in the welding zone causes the metals to exhibit molten or semi-molten behavior, so the joint becomes a continuous material. A filler welding wire is often used, contributing to strength and integrity.

Main welding technologies (MIG/MAG, TIG, MMA, laser welding)

• MIG / MAG: popular in industry due to speed and good adhesion with various materials. Suitable for fast welding of steel and structures.
• TIG: used when an extremely precise weld is required (e.g., stainless steel, aluminum), though the process is slower.
• MMA (manual arc welding): often applied in repairs or hard-to-reach areas.
• Laser welding: very precise and fast, especially when structural components require minimal thermal distortion.

Applications in the B2B sector: structures, frames, pipelines, industrial parts

For business clients, metal welding is applied in many ways: industrial equipment frames, packaging equipment, brackets, machine parts, pipelines, racking, bridge structures. A long-lasting structure requires welds that withstand loads, vibrations, and environmental effects.

Unique insight: Companies often don’t consider that the welding zone behaves as a localized region of weaker material. Therefore, it’s worth planning reinforcements, offsets, and thermal stress compensation already at the design stage to prevent later damage to the structure. This is exactly the level of technical attention provided by “Metalo Asai” — we collaborate with the client from the design stage to ensure optimal weld joints and long-term quality.

Why choose a certified welding partner

Operating in the B2B sector, large projects often require documentation, compliance with standards, and consistency. From a simple buyer’s perspective, it may seem that “a good craftsman will weld it” is enough — however, in the long run, improper practice can result in costly repairs, warranty claims, or even reputational risk.

ISO/EN standards (ISO 9606, ISO 3834, EN 1090)

• ISO 9606: a welder qualification standard proving that welders are technically capable of performing the work at the required level.
• ISO 3834: a quality management standard for the entire welding process, covering procedures, documentation, and control.
• EN 1090: important if your structures will be sold or used in construction under the European CE marking.

Audits, records, and quality control processes

A certified partner has consistent procedures: welding procedure specifications (WPS), record keeping, test documentation, and quality audits. This allows the client to accurately monitor the entire process and participate in control.

Risk reduction in case of defects and repairs

If a weld fails, cracks appear, or corrosion develops — it can lead to technical failures, production downtime, or even fires. A certified partner reduces the likelihood of such risks and can offer warranties for repairs. Metalo Asai values continuous quality monitoring — we offer to include independent NDT testing for each structure whenever the client requires it.

Preparing metal structures for welding

One of the most often overlooked yet critically important steps is proper preparation of structures before welding. If this is not done well, the final joint may be weaker, deformed, or contain defects.

Design, drawings, tolerances

Before production begins, a clear structural specification is required: definition of tolerances, joint locations, and weld directions. Sometimes it is worth clarifying with the client where reinforcements or stress-relief grooves are needed in the weld area.

Material preparation: grinding, cutting, cleaning

The metal surface must be clean — free of rust, paint, oil, and contaminants. The edges of the joint must be precisely beveled. Milling or CNC machining is sometimes required so that mating surfaces fit together perfectly.

Fixturing and positioning

Workpiece stability and fixturing (clamps, positioning tables) help avoid movement during welding, which can cause inaccurate welds or residual stresses. Proper positioning — horizontal, angled — affects weld quality.

Unique insight: Most clients don’t realize that even deviations of a few tenths of a millimeter before welding can result in a critical gap after welding, especially in large structures. The Metalo Asai team performs accuracy checks already at the workpiece stage using 3D measurement devices to eliminate minimal deviations before the welding cycle.

Welding processes and technologies

In this section, we discuss the main welding technologies, their application to structures, and recommendations on when to use each option.

MIG / MAG welding (advantages, disadvantages)

• Advantages: high working speed, broad material compatibility, relatively easy to automate.
• Disadvantages: heat input can be harder to control, which means a higher risk of distortion. This technology is often applied to large steel structures when subsequent operations can compensate for thermal distortion.

TIG welding (when it’s suitable)

TIG enables exceptionally high-quality welds and is especially suitable for stainless steel, aluminum, or where aesthetics and a small heat-affected zone matter. The process is slower, but the end result is cleaner and more reliable.

MMA (shielded metal arc) welding

Used mostly for repairs and in dark or narrow spaces where it’s difficult to apply MIG/TIG. While the welds can be rougher, it is a practical choice when the structure is already installed on site.

Automated and robotic welding

In high-volume production and serial manufacturing, where precision and speed are crucial, robotic welding ensures consistency between batches. It also reduces the likelihood of human error and improves productivity.

Laser and plasma welding

When a very narrow heat input, high precision, and low distortion are required, laser welding is an excellent choice. It is often used in high-quality electronics, medical devices, or precision industry.

Unique insight: One of Metalo Asai’s differentiators is optimizing welding parameters according to the designed load. We don’t copy “standard” parameters — we analyze the client’s structural load, thermo-elastic zones, and tailor curve modifications in the initial welding plan accordingly. This reduces residual stresses and increases the structure’s service life.