• Medium and Heavy Steel parts

    Advice + Experience + Quality
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Certified by TüvRheinland

Certified by TüvRheinland

Soldadura homologada

Welding procedures
Qualified Welders and Welding Operators


Constant inhouse and external inspections to provide the best quality

Production Process

Our technical office linked to the assembly capacity of large and complex structures and thanks to the quality controls make us a competitive company at European level.


Technical Office R & D

We have human and technical capacities for the development of your projects.

We also have suitable means to work on drawings of parts or assemblies of all kinds using 3D software applications. Using customer’s drawings we produce our own constructive and assembly plans necessary for the manufacturing process.The assembly sequence of parts is made taking into account always the deformations and contractions usual on welding processes.

These skills allow minimizing errors on parts achieving the highest levels of constructive requirements.

Software 3DWe always do a review of customer specifications and a technical review:

Specifications of required materials.
  Specifications of welding procedures.
  Required Welding qualifications.
  Non-Destructive Test (NDT) procedures.
  Heat treatment procedures.
  Quality control agreements.
  Inspections and testing.



The previous operations are clearly identified in the documentation generated by our technical department to avoid possible errors. We pay special attention to pre-machining operations, welding sequence, accessibility, etc.

At Juan Lasa all the parts assembly are made taking always into account the final machined part drawings.

We always check all the measurements and the excesses. We assure the geometry of the welded part.




According to the machining drawings:

  Previous machining.
  Preparation of welding joints.
  Accessibility and welding sequences.
  Perpendicularity and parallelism.
  Deformation of the welds.
  Accessibility for inspections.

Welding and NDT Inspections

Welding Procedures:

WPQR: Welding procedure Qualification record according to UNE EN ISO15614, ASME and AWS standards.

WPS: Manufacturer's welding specifications.

Welders and Welding Operators qualified.

Decades of experience in submerged arc welding (SAW), offering robust, uniform and high penetration welds. Ability to handle parts up to 32 Tn.


Large capacity installations for automatic welding processes.

Soldadura automática
Soldadura automática
Soldadura automática

Bonding weld 100% of thickness. Inspected by Ultrasonic (US) and Magnetic Particles.(MPT)

During the manufacturing process, we can perform weld inspections through non-destructive testing. These tests use different techniques such as Magnetic Particles (MP), Penetrant Liquids (LPT) and Ultrasounds (UT).

We also provide industrial radiographs (X-rays or gamma).

We have certified technicians, holders of CERTIAEND Level II certificates, enabling them to issue reports on all three types of tests.


High skilled and experienced welders: instructed in Visual Inspection. In addition, our inspectors examine all welds using the Penetrant Test to ensure 100% proof welds.


Oxicorte e instalación de materialesWe oxy-cut all types of parts in the grades S 275 and S 355, the thicknesses usually being between 8 and 200 mm.

Our manufacturing systems allow direct communication between the computers and CNC control of the machines, with which we achieve a faster response to the needs of our customers.

We use ultrasonic technology for the inspection of materials, and we can issue homologated reports at the request of the client.

Finished steel constructions according to customer specifications

Stabilized welding - Heat treatment

After the stresses generated by the welding, we manage its stabilization to eliminate them, by techniques of THERMAL TREATMENT and STABILIZED BY VIBRATION. A graph of the entire process is generated showing the heating, maintenance and cooling times.

Shot blasting

We apply shot blasting to remove surface impurities from industrial sheets, and also those produced during the oxygen cutting and manufacturing process. The oxide generated during the heat treatment is also removed. ISO standard 8501-1 Shot blasting Sa 2½


The application of the printing paint after the shot blasting process allows adequate protection of the workpiece surface. The quality and thickness applied are those requested by the customer.

Finishing operations in Juan Lasa

Depending on customer's specifications, parts can be subjected to complementary processes such as screw re-profiling, surfaces polishing, application of grease coatings for surface protection, etc.

Parts Machining

If the customer requests machining the part before expedition we, at Juan Lasa, have a long and close relationship with the best local machining companies, offering the best ratio Quality/Price.


We also offer regular transport services throughout Europe with the best international agencies, including special transport.


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