First-Class Welding Quality for First-Rate Freight Wagons

Application Story

6/25/2024

Deutsche Bahn’s freight wagons are manufactured by the company Tatravagónka in Tlmače, Slovakia and have to withstand enormous tractive forces and axle loads of more than 22.5 metric tonnes (EN 15687:2010). The company specializes in the production of 6-axle articulated wagons for transporting containers and swap bodies, which are used on wide and standard-gage railways. The welding work required is carried out using the TransSteel 5000 Pulse from Fronius, a robust welding machine that is ideal for welding steel and carbon steel alloy subassemblies.

Tatravagónka is one of Europe’s leading manufacturers of freight wagons for container transport. Its product range is closely linked to that of its Poprad-based parent company, which has a portfolio of more than 100 different types of wagons. Under the slogan “We want to be first choice for freight wagons,” its Tamns-design 4-axle wagon with sliding roof was awarded the honor of best mechanical engineering product of 2018 in Slovakia. This wagon design has completely eliminated the possibility of moisture ingress into the interior, a common problem when transporting raw materials. This makes it ideal for transporting moisture-sensitive bulk materials such as gypsum. Tatravagónka also has a patent for steel folding roofs with double labyrinth seals, which ensures that the bodies are watertight.

Certified for Rolling Stock Construction

The company, based in Tlmače, is certified under EN 15085-2, classification level CL 1 for railway applications – Welding of railway vehicles and components and under DIN EN ISO 3834-2 – Quality requirements for fusion welding of metallic materials. The company employs experienced welders who weld in compliance with its internal Welding Procedure Specifications (WPS). These are prepared by the firm’s highly qualified welding monitoring team.

Quality as a Benchmark—Including for Welding Machines

The experts at Tatravagónka rely on the TransSteel 5000 Pulse from Fronius. With up to 167 optimized characteristic curves, it has process variants that are in demand in many industries. Its versatility is particularly evident in its design featuring the pulse function, with the welding machine delivering outstanding results for aluminum, steel or stainless steel. Pulse welding enables higher welding speeds for larger material thicknesses while also generating significantly less welding spatter and reworking compared to the standard process: a tangible commercial benefit for Tatravagónka. If welding work is carried out in awkward conditions using the pulsed arc (for example overhead), the arc pressure can be increased using the pulse correction feature. This prevents the weld pool from escaping.

The dynamic correction feature can be used if more penetration is required for optimal root formation when welding thinner sheets with the standard arc. A harder and more stable arc can be generated by reducing the short-circuit dynamics at the moment of droplet transfer. When welding thicker sheets with the standard arc, a soft, low-spatter arc can be generated by increasing the short-circuiting dynamic. In special 4-step mode, it is also stabilized during ignition by reducing the power. Tatravagónka welders can place uniform welding spots at regular intervals using spot mode. The pause time between the intervals can be freely selected and is therefore ideal for tacking workpieces.

“Welding in overhead and horizontal positions (PE and PC) requires special skills from our welders. The welding equipment also plays a crucial role in achieving the required results,” explains Jaroslav Nemergut, Technical Director at Tatravagónka Tlmače. “Fronius has the perfect welding machine for our needs in the form of the TransSteel 5000 Pulse and its functions for welding heavy steel. But that’s not all: The customer-friendly service package also included bespoke commissioning training and a specially developed custom solution for supporting and routing our hosepacks.”

EasyJobs at the Touch of a Button

Using the Up/Down welding torch, the welding experts at Tatravagónka can save up to five “EasyJobs,” which can be selected directly from the torch when the EasyJob Trigger (EJT) is activated. Fronius provides welding characteristics for this that are specially tailored to welding steel for various tasks:

STEEL is the universal welding characteristic for quick, easy welding applications.
STEEL ROOT is the welding characteristic developed specifically for root pass welding. It boasts exceptional gap-bridging ability and the capability to fill wide air gaps.
STEEL DYNAMIC is a welding characteristic with a particularly hard, concentrated arc. The results include high welding speeds and deep penetration.
PCS (Pulse Controlled Spray Arc) welding characteristic enables a combination of intermediate and spray arcs, providing deep penetration with minimal spatter.

“The TransSteel is easy to configure. When one parameter, such as the amperage, has been set, the algorithm of the convenient Synergic function automatically calculates the other parameters. Depending on your needs, you can choose between Standard Synergic, Pulse Synergic or Manual,” says Welding Specialist Rey Jumaquio enthusiastically.

Ready to Weld in Three Steps

The TransSteel's range of functions has been deliberately reduced to the essentials. The focus is on the greatest possible clarity and easy handling. This allows the welding specialists at the Slovakian wagon manufacturer to concentrate on the weld pool and not waste any time with awkward operation.

Whether you are an old hand with the TransSteel or using it for the first time, the device is ready for welding in just three steps, even if you have zero previous experience with it. Welders use the pressure-active buttons and rotary knobs on the front of the housing to set parameters, such as shielding gas, wire diameter, and material thickness. In these times of skills shortages, the fact that it is so easy to use is a huge plus for Tatravagónka. It means that semi-skilled workers can operate the welding machine with only brief training and weld less critical components to the desired quality level. With a duty cycle of 40% in the maximum power range, the TransSteel offers around one minute more productivity time than the average machine in this power range.

Another benefit that facilitates welding in Tatravagónka is the convenient Synergic function for MIG/MAG Standard Synergic and MIG/MAG Pulse Synergic welding processes: If just one of the material thickness, welding current or wire speed parameters is selected, the other parameters, including the welding voltage, are set automatically.

Precision and Safety

The central control and regulation unit of the TransSteel is coupled with a digital signal processor. Together, they control the entire welding process. Actual data is continuously measured so that the system can react immediately to changes. In this case, rule algorithms ensure the desired state in a fraction of a second. This provides three noteworthy benefits for all welders at Tatravagónka: high process precision and reproducibility of welds as well as excellent weld properties.

The universal welding machine also boasts some impressive safety features, including the Voltage Reduction Device (VRD), an optional safety device that reduces the voltage between the electrode and the workpiece when required, such as when working in a damp environment. This significantly reduces the risk of electrical accidents caused by arc welding.

Patented Multi-Lock Interface for Welding Torch

The interface allows Tatravagónka welders to adapt MIG/MAG welding torches specifically to the relevant requirements. The wide choice of torch bodies in terms of lengths and angles ensures that even hard-to-access parts can be welded easily. In case of doubt, the best option is a flexible torch body. The Fronius System Connector acts as the central connection point for all media. This enables welding specialists to connect a wide variety of different welding torches.

Easy Documentation

Standard-compliant welding is the order of the day at Tatravagónka. This means that the requirements of the Welding Procedure Specification (WPS) need to be strictly adhered to during the welding process. The TransSteel 5000 Pulse’s Easy Documentation option saves the key welding data for each individual weld in CSV format on a USB stick. A Fronius signature is also saved to verify and guarantee the authenticity of the data.

Welding Tractor for Longitudinal Seams

The huge tensile forces and axle loads of freight wagons sometimes require welds extending several meters to be of consistently high quality. If the welding is completed manually, the required consistency in terms of the A dimension and weld appearance is very difficult to achieve. The four-wheel-drive ArcRover magnetic welding carriage from Fronius in combination with the TransSteel 5000 Pulse is the solution. It is ideal for welding single-layer fillet welds on steel beams and sections, common practice at Tatravagónka. It can maintain constant speeds of up to 250 cm/min in all positions.

“We are very satisfied with the welding solutions and partnership-based services from Fronius,” says Nemergut in summary. “In addition to the standard package, such as training and commissioning, the Austrians also provide welding training and certifications. Some of our experienced welders have now been trained and certified by the Fronius Welding Business Academy for special aluminum welding work. This will enable us to expand our product range with further wagon bodies.”

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