András Brautigam

57437658300

Publications - 5

Laboratory Investigation on Seams between Rails and Hardened Fine-grained, as well as Hadfield Steel Plates with Manual Arc Welding

Publication Name: Acta Polytechnica Hungarica

Publication Date: 2025-01-01

Volume: 22

Issue: 4

Page Range: 83-102

Description:

In the last decade, hardened fine-grained plate components have been used in turnouts and crossings on Western European urban rail networks, as well as in Hungary, in place of traditional rail or Hadfield steel components. The first crossing was built in Hungary in 2016. These components have many advantages, such as the ease with which they can be machined in the factory; they are less prone to cracking than rails due to their block design (high load-bearing cross-section); however, their weldability to rails and lifetime repairability present numerous challenges for railway turnout manufacturers and operators. There have been numerous studies on joint and repair welding of rails and hardened finegrained materials, but there is little or no information available on joint welding with manual arc welding of these two different materials. The current study aims to investigate the welds of coated electrode manual arc welding of rails (R260 and R400 HT) and hardened finegrained plates (in this case, Hardox 500) under non-laboratory conditions while strictly adhering to technological specifications, in comparison to manual arc welding of rails and Hadfield steels. Laboratory tests included raw material chemical composition, macroscopic tests, micro-hardness measurements, tensile, shear, and bending tests.

Open Access: Yes

DOI: 10.12700/APH.22.4.2025.4.6

Field Application of Austenitic Filler Metals for Repairing Rail Surface Defects in Paved Tracks

Publication Name: Lecture Notes in Networks and Systems

Publication Date: 2025-01-01

Volume: 1258 LNNS

Issue: Unknown

Page Range: 87-95

Description:

Previous research by the authors identified a welding technology to repair rail defects in tramways with partial disassembly and partial preheating, with the following main advantages for the operator: the process can be carried out during operational downtime or even during traffic, disassembly, and repair costs are reduced, and traffic disruption is reduced compared to conventional hard surfacing welding technologies. After welding, the hardening under traffic should approach the vehicle wheels’ hardness values (310–350 HB). In the track measurements under investigation, welds were made on two different rail grades using austenitic weld metal with high elongation relative to the rails, which was also compared with welds made by conventional hard surfacing welding. The present study aims to determine the hardening function of austenitic dowel bars at different layer counts by performing continuous hardness measurements at the investigated sites. The hardening shows a power function at the initial stage and a linear trend after about 2.5 million MGT.

Open Access: Yes

DOI: 10.1007/978-3-031-81799-1_9

INVESTIGATION OF HEAT-AFFECTED ZONES OF THERMITE RAIL WELDINGS

Publication Name: Facta Universitatis Series Mechanical Engineering

Publication Date: 2024-12-01

Volume: 22

Issue: 4

Page Range: 689-710

Description:

The paper investigates the heat-affected zone (HAZ) of several rail joints executed by thermite rail welding (TW). The examined rail profile was 54E1 (UIC54). The rail steel categories were different: R260 and R400HT. The welding portions of the TWs fitted R350HT and R260 rail categories with normal welding gaps. The rail pieces were brand new, i.e., without any usage in the railway track. The authors executed Vickers-hardness tests (HV10) and material texture tests on the running surface of the rail head, as well as on slices cut from the rail head. The cutting was performed by the water jet method, five longitudinal direction slices with vertical cutting lines. The considered specimen lengths were 2×70 mm (i.e., 70 mm from the mid-point of the rail joint), however, the depths were 20 mm from the running surface. Therefore, the measuring spaces were 5 mm lengthwise and 2 mm in depth. The variation of the hardness values was determined considering the microstructures of the base steel material and the TW. For comparison, previously measured Elektrothermit SoW-5 and earlier own research were taken into consideration.

Open Access: Yes

DOI: 10.22190/fume221217008f

Sustainability in Railways – A Review

Publication Name: Chemical Engineering Transactions

Publication Date: 2023-01-01

Volume: 107

Issue: Unknown

Page Range: 7-12

Description:

This paper examines the sustainability of railways. A comprehensive international literature review was conducted on railway vehicles, traction, and railway permanent way. The main goal was to find the factors and parameters that affect railway sustainability the most. CO2 emissions from transportation, mining, raw material production, manufacturing, use, operation and maintenance, and demolition and restoration must be significantly reduced. Naturally, the attention will be on the considerable energy and financial savings. This article's main topics are sustainability, affordable and clean energy, industry, innovation, infrastructure, sustainable cities and communities, responsible consumption and production, climate action, and life on land. Building materials come from quarries and gravel pits, but availability is decreasing. Future pavement construction and maintenance require recycling demolition and industrial waste. Engineers must choose materials and technology that extend track lifetimes to ensure reliability, availability, maintainability, safety, sustainability, and economy in permanent railroad ways. Life-cycle costs can be reduced, e.g., by Building Information Modeling. Electric machinery is preferred for construction equipment, materials, and management. Sustainability, like grassed tracks and recyclable plastics, has improved urban life. Sheet metal forming using recycled materials and sustainability shows how important environmental protection is in car and train design. Electric road and rail propulsion are driven by environmental concerns, while supercapacitors and batteries are studied. In conclusion, by preferring rail for freight and passenger transport, both for private and public transport, energy savings and CO2 emissions can be up to 2-10 times higher than for other modes of transport.

Open Access: Yes

DOI: 10.3303/CET23107002

Investigation of the Effects of Thermit Welding on the Mechanical Properties of the Rails

Publication Name: Acta Polytechnica Hungarica

Publication Date: 2022-01-01

Volume: 19

Issue: 3

Page Range: 37-49

Description:

This current paper deals with the investigation of the variation of the hardness of the rail steel material in the heat-affected zone (HAZ) of a rail joint made by thermit welding (TW). The tested rail is a normal R260 type rail steel category; its production date is 1977, the rolling mill was Diosgyor (Hungary), rail profile is MÁV 48.5. This rail has not been in railway track before the test. The authors performed hardness tests on the rail head’s surface even after the rail welding, as well. After the welding and hardness tests, the rail joint was cut with +/–200 mm by a rail cutter and transported to the laboratory. Water jet cutting was applied to shape six longitudinal direction slices with five vertical cutting lines from the rail piece’s head. The slices’ length was 400 mm, the width of these slices was approx. 10 mm; the TW rail joint was in the mid-point of the slices. Micro-Vickers (HV10) hardness tests were executed on these slices, in the –150…+150 mm interval lengthwise and in the 3, 6, and 10 mm depth points below the rail head’s top surface. As a result, the authors received a very detailed hardness functions of the HAZ of rail joint made by TW. These variation functions were compared to the official Elektrothermit’s SoW-5 hardness tests’ results. It can be concluded that the variation of the hardness of rail steel in the area of the HAZ correlated with the Elektrothermit’s results; however, there were some critical points where significant differences were able to be found. The highest deviation was concluded in 50 mm distance measured from the axis of welded rail joint. The authors gave possible valuable explanations for these phenomena.

Open Access: Yes

DOI: DOI not available