Eines der zahlreichen Forschungsexperimente, die das interne Team von SLTL durchgeführt hat, legt nahe, dass das Laserschweißen im Vergleich zum herkömmlichen Schweißen eine höhere Schweißfestigkeit bietet
The train network in India is very extensive and accommodates a lot of frequently traveling passengers as well as the transport of heavy goods for the booming industrial needs. India’s important energy sector relies on coal and thermal fossil fuels, which were readily available to industry via the train network. Under this strain, the railway always strives to make maximum use of its routes and capacities.
Recently, Indian Train bogie manufacturing company ICF Indian Coach Factory surpassed the long-standing industry leader to become the world’s largest railway bogie manufacturing unit by producing more than expected in the financial year 2018-19. Due to India’s diverse terrain, railways seem to be the perfect transport for both passenger and freight services. The industry is challenged to improve current capacity to build train bogies with increased strength and ergonomics.
To understand the scenario, we need to look at the existing technology for welding train bogies. Understanding the scope of possible improvements and alternatives.
Before the introduction of fiber laser technology, the industry used MIG and TIG welding to weld sidewalls. These techniques were quite outdated and allowed for minimal upgrades over the last decade. When using these conventional methods, other processes must be combined to meet increasing aesthetic and strength requirements. Here are some disadvantages of the systems:
- Using shielding gas when welding can prove costly
- MIG welding requires great dexterity and skill
- GMAW welding requires significant amounts of heat
- Heat is transferred to the metal workpiece and can cause deformation and also a change in the structure of the metal, which can lead to weak points in the welds
- Susceptible to contamination
- High setup costs
- UV rays can cause burns
- Is limited to draft-free conditions
- Requires high skills
- Equipment and supplies are expensive
- Not portable and unsuitable for outdoor welding
- Due to the fluidity of the weld, use in vertical or overhead positions is not possible
A new approach
At SLTL Group, we focus on continuous innovation and consider innovation is a never-ending process. One of the numerous research experiments conducted by SLTL’s in-house team suggests that laser welding offers higher weld strength (up to 59%) compared to traditional welding. The team conducted industry standard and specialized testing to ensure the excellent quality of the weld. The team achieved successful results in the tensile and bending test, hardness test, macrostructure test, liquid penetrant test and 180 degree bend test of the weld joint. From now on increasing the safety factor of a wagon. The machine’s ability to perform efficient welding improved the overall aesthetics.
- Weld strength: The laser weld is narrow with an excellent depth-to-width ratio and higher strength.
- Heat Affected Zone: The heat affected zone is limited and due to rapid cooling, the surrounding material is not annealed.
- Metals: Lasers successfully weld carbon steel, high-strength steel, stainless steel, titanium, aluminum and precious metals as well as dissimilar materials.
- Precision work: The small, strictly controlled laser beam enables precise micro-welding of miniature components.
- Deformation: Parts exhibit minimal deformation or shrinkage.
- No Contact: No physical contact between material and laser head.
- Single-sided welding: Laser welding can replace spot welding, which only requires access from one side.
- Scrap: Laser welding is controllable and produces small amounts of scrap.
Train Bogie laser welding machine
With all the experiments and conclusions drawn, the team at SLTL essentially created the first-of-its-kind laser welding machine for railway bogies. The machine supports sheets with solid structure and allows fine alignment of the sheet for welding. The convenient integrated vision system makes it easy to spot small gaps (often invisible to the naked eye) and properly align sheets for welding. The laser welding process then carried out produces a continuous laser beam on the component and creates a flowing weld line. The process requires minimal space and gives the resulting component unparalleled strength. With machines like this, Indian Railways thrives with excellent build quality.
