Specialized Welding Expertise Since 1963

With broad expertise, modern production, and certified processes, we deliver projects that meet high demands for safety, quality, and long-term sustainability. Our customers can rely on us to manage the entire project, from concept and design to final product and installation. As a partner, we always strive to create added value, not only in the solution itself but also in the collaboration and the trust we build.

We are Sonstorps Mekaniska

Since our founding in 1963, Sonstorps Mekaniska has grown from a one-person operation in Sonstorp outside Finspång into a modern company with around 45 dedicated employees. For more than 60 years, we have continuously expanded both our offering and our capabilities, from welded beam structures and lifting tools to advanced turnkey solutions for bridges, bridge decks, and large industrial projects. Over the years, we have built extensive experience in combining craftsmanship with structured project management, always in close collaboration with our customers. This has earned us a strong reputation within both infrastructure and the manufacturing industry.

Where We Make a Difference

From bridges and advanced industrial production to innovation and product development. We are present wherever society evolves.

Our three business areas; Infrastructure, Industry, and Innovation/Product Development reflect the breadth of what we do.

Infrastructure

We are a reliable partner in infrastructure projects where the requirements are high. Our bridges, bascule structures, guide frames, dam gates, and ferry berths are manufactured through certified processes according to EN 1090-1, -2, and -3, ensuring quality at every stage, from drawing to completed structure.

Industry

We deliver robust structures for the industrial sector, everything from machine foundations, pressure vessels, and crane rails to special tools, mezzanine floors, platforms, and lifting equipment for turbine assembly. With qualified welding, extensive experience, and close collaboration with our customers, we develop solutions that withstand demanding environments and meet the highest requirements.

Innovation & product development

We are driven by the desire to make things smarter, simpler, more sustainable, and more value-creating. Whether it’s improving an everyday industrial product, supporting students with prototype manufacturing, or developing a completely new solution from the ground up, we believe in the power of new thinking. By challenging today’s solutions, we create opportunities to build better, better for the environment, for the user, for the design, and for the economy.

Certifications

At Sonstorps Mekaniska, quality, safety, and sustainability form the foundation of everything we do. Our certifications according to ISO 9001, ISO 14001, ISO 3834, and EN 1090 ensure that we deliver according to the highest standards. These certifications are not only proof of our competence, but also a promise to our customers: that every project meets industry requirements for quality, environment, and safety regardless of its size or complexity.

With a strong focus on precision, documentation, and long-term sustainability, we create products and solutions that stand the test of time and contribute to an industry and infrastructure built to last for generations.

Below you can read more about what each certification entails

International standard for quality management. Demonstrates that we work systematically with processes, continuous improvement, and customer satisfaction at the center.

Ensures that our operations are managed with consideration for environmental impact. We actively work with resource efficiency, reduced emissions, and sustainable choices.

We are certified at several levels, enabling both simple and advanced welding projects to be carried out with the highest level of quality.

A mandatory standard for manufacturers of load-bearing welded structures. We are approved up to Execution Class EXC3, allowing us to deliver to complex and safety-classified construction projects.

Certification that enables us to meet North American welding requirements. Shows that we also have the capacity to take on projects with international specifications.

Standard for the design, manufacturing, and testing of unfired pressure vessels. We manufacture pressure-retaining components according to EN 13445 with a strong focus on safety, durability, and quality in every detail, always in compliance with the PED directive.

Standard for metallic industrial piping systems subjected to pressure. We follow EN 13480 in the production of piping systems and associated components where safe operation, pressure resistance, and correct documentation are essential.

Robot welding

Our robotic welding cell is designed to handle large steel structures, with a working area of 5 × 3 × 48 meters. Two welding heads enable simultaneous work at multiple points, ensuring efficient production and consistent quality. The facility is used, for example, for welding beams, bridge components, and other large-scale structures. 

The robotic welding system complements our overall production and allows us to combine automation with our welding expertise. This means we can deliver large series with high repeatability while also adapting to special projects with unique requirements. 

Vision and goals – together for a sustainable future

Our vision is to be a leading provider of welded steel and aluminum solutions in Sweden. Our goals are to grow sustainably, increase our production capacity, and broaden our offering, all without losing the personal customer relationships and high quality that define us.

Goal 9 – Industry, Innovation and Infrastructure

We develop innovative and sustainable solutions for the industry of the future, such as lightweight aluminum bridges and flexible welded constructions.

Goal 11 – Sustainable Cities and Communities

We contribute to the development of Sweden’s infrastructure, bridges, road structures, and specialized solutions, strengthening communities and transportation systems.

Goal 12 – Responsible Consumption and Production

Through efficient use of resources, circular thinking, and long-lasting products, we minimize environmental impact at every stage of the value chain.

Goal 13 – Climate Action

We work with energy-efficient production methods, green technology, and sustainable material choices to reduce our climate footprint.