Friday, July 13, 2012

Rail welding brings more than flash

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A welding truck from Holland L.P. A welding truck from Holland L.P.

Quality, reliability and safety are issues suppliers look to improve when it comes to the subject of welding rail.

Track time is always an issue and railroads need welds that can be completed quickly without losing any quality. Whether it's a turnkey service for better personnel utilization, making sure employees are properly trained, reducing the soft areas of the heat-affected zone or automating the welding process, suppliers are focused on providing welding systems and services to meet the railroads' needs.

Mobile fleet

Chemetron, a division of Progress Rail Services, has added a boom truck to its mobile welding fleet. The unit has a 20-foot reach, allowing turnouts to be constructed in the field with electric flash-butt welds. The unit has hi-rail, enabling travel between worksites on the highway or rail. It can also be used for many industrial rail welding applications.

"Our customers demand safety, quality and reliability in ever-shorter work windows. We have made a number of improvements at our fixed and mobile operations to meet customer expectations for quick train turns at our welding plants and no missed welds in the field. Our electric flash-butt weld quality and equipment reliability has been superior," said Mark McLean, manager sales.

He added, "Chemetron continues to add capacity to meet the growing demand for electric flash-butt welding. We have added a number of trucks to our fleet of mobile welders and have extra shifts/crews at most of our fixed plants to meet our customers' needs."

Turnkey welding

Holland L.P. has been working with Class 1 railroads to provide turnkey welding services for in-track welding projects.

"The turnkey service addresses the logistics and requirements for additional personnel on a temporary basis. This allows the railroad to better utilize their experienced personnel. Our depth of experience allows us to support our core competencies with people and equipment related to in-track welding," said Richard Morris, director new business development, Welding Group.

A two-year development program between Holland L.P. and Edison Welding Institute culminated in June when Holland entered revenue service with its new Head Defect Repair welding equipment. The process removes a railhead defect by cutting a notch from the railhead and electric flash-butt welding a rail steel insert into the notch. Morris says the process has been through extensive testing; including sample welds in track at TTCI that have exceeded 250 mgt to date.

The Head Defect Repair welder (HDR) is a process that repairs defects such as transverse defects, detail fractures and small surface defects. The process allows the rail to be repaired without severing the rail or installing a replacement rail.

"One advantage with this process is the neutral rail temperature is not disturbed. Also, this process requires considerably less manpower than other flash-butt welding processes to complete. The HDR process provides electric flash-butt weld quality at a cost comparable to other methods currently available to the railroads," said Morris.

Morris points out that the railroad industry in general has been moving away from manufacturing specifications and moving toward performance specifications.

"We have been able to use welding technology from other industries to develop welding programs like Low Consumption Welding. This weld program is beneficial in repair welding applications. A Low Consumption Weld reduces the amount of labor required and improves productivity by minimizing the number of rail anchors that must be removed," said Morris.

He also mentions that as the rail steels become more durable, it is necessary to continue to improve the joining process. One area Morris says has room for improvement is the heat-affected zone (HAZ) of a weld, which represents a disruption in the surface continuity of the rail and has been a focal point for weld improvement. He notes that Holland is working on methods to reduce the soft areas of the HAZ without significantly increasing weld hardness.

"Holland is committed to continually growing its business by developing products and services that provide a value to the railroad industry. Holland has put together a group specifically for developing new products and services. The group's first project is the Head Defect Repair Welder. Future projects are looking at field repair of special trackwork, welding turnouts and long rail distribution systems," said Morris.

Railroad welding Lincoln ElectricImproved training

Lincoln Electric has added more emphasis on technical field support by expanding the current training done with the manganese frog welders to include the roadway equipment repairmen, who have smaller Lincoln Electric engine drive welding machines.

Brian Meade, manager railroad technical services-global accounts, said in the past, there was not a specific part of the training program that included equipment mechanics who had the company's new welding equipment on their trucks and used it for repair welding from time to time but were not full-time welders.

"Unlike the manganese frog welding crews that weld on mostly the same castings daily, the repairmen can encounter various types of base metals that need weld repaired. Lincoln has expanded it's training to include a better understanding of the equipment and how to control the welding output, plus methods to identify the different base metals and how to address welding on the parts. This will allow welders to repair equipment parts that will help reduce the need for purchasing new parts," said Meade.

Meade also mentions that the training of the manganese frog welders is an ongoing process and points to two main reasons: first, the company's Air Vantage 500 has received new design features over the past several years and the trucks with the new units are being distributed to new locations. Second, the company has new welders coming into the positions for the first time who need to be trained on welding equipment they have no prior experience using.

"We see the rail market as continually requiring technical support and growing into areas where training has not been a past focal point. Involving part-time welding with the full-time welding crews will provide immediate solutions to the railroads. As we go forward, we see the partnerships expanding to cover new areas in the engineering departments, with new improvements and design changes being considered as a priority," said Meade.

Head alloyed welds

"Orgo-Thermit, Inc.'s, patented Thermit® Head Alloyed Welding technology allows Thermite welding of the new high hardness, high strength rail steels, which have Brinnell Hardnesses in excess of 380. These special purpose welds use a unique micro-alloying process, producing excellent wear properties, on the running surface of the rail, while maintaining softer and more ductile properties in the metal at the base of the rail. Ten of these welds were installed in February of 2011 at TTCI's FAST track, where they continue under heavy-axle-load testing. The company says that, to date, all of the welds installed have accumulated more than 234 mgt, with no service failures," said Dave Randolph, president.

The company began its Technical Services Division in 2011 to focus on its shortline and transit operations. Randolph notes that since the introduction of the Technical Services Division, Orgo-Thermit's customers have utilized its services for non-destructive testing for Ultrasonic and Brinell hardness, as well as the company's Slow Bend Testing and weld failure analysis services.

"We are seeing greater interest in our Safe Start Electronic Ignition System, which is non-hazardous and has no shipping restrictions. We are working on improving this safer method of initiating Thermit reactions via remote control," said Randolph. "Our customers are very happy that all of our consumable materials continue to be Buy America compliant, with all production at our Manchester, N.J., facility."

He continued, "Our outstanding growth in sales demonstrates that the rail welding market is very strong. We remain positive about the future of Orgo-Thermit and the railroad market. Our on-going goal is continuing to work toward providing innovative solutions to our customers."

Robot welding

Plasser American Corp. points to its many years of experience in the production and operation of rail bound, hi-rail and container flash-butt welding machines and mentions that new welding standards have resulted in an increase in welding requirements.

"Conventional weld heads used up to now are mostly based on a Russian patent and do not or only partly meet these new requirements," said Plasser American Corp. "More stringent requirements, combined with Plasser's knowledge gained over many years resulted in the development of its own automatic welding robot."

The company says a key feature of this new weld head is its working parameters of 200mm stroke with 150 tons of force, which allow closure welds to be made without the use of additional rail pullers.

Welds made by Plasser's APT 1500 R welding robot utilize a fully-automatic process. The welding head automatically aligns the height and running surface, as well as crowns the rail. The automatic centering device measures rail alignment via distance transducers located in the weld head. The measurements are saved for quality assurance reasons," said Plasser.

Another special feature the company points to on the weld head is its utilization of alternating current with a medium frequency of 1,000Hz allowing the use of very small transformers in the weld head. The head runs on direct current, which Plasser says has a positive effect on the weld quality.

"The built-in welding shear places a load only in the direction of compression utilizing separate hydraulic cylinders. A non-contacting temperature measuring system allows for the precise cooling of high alloy rails with the help of a post heating process. The hydraulic system allows for very fast movements of the weld head, even for closure welds under full load (low consumption weld). The design of the clamping jaws eliminates the need to grind off company markings on the rail web, thus reducing preparation time," said Plasser.

"With the automatic robot welding process, operator errors can be ruled out. The result is high reliability and documented welds of consistent high quality," said Plasser.

Railroad welding Railtech BoutetAluminothermic weld system

Railtech Boutet says over the past year, it has continued pushing its new ignition system, Startwel®.

According to the company, the Startwel Ignition System allows the welder to easily ignite the weld charge to initiate the pour process for the Railtech Aluminothermic Weld System, replacing the tradi¬tional "sparkler" igniter design.

"This new electric ignition system is safer than today's traditional igniters. In addition, Startwel is classified as non-hazardous for transport. Therefore, there are no shipping restrictions (can be shipped overnight if there was an emergency) and it provides more accurate and consistent tap time," said Oliver Dolder, executive vice president and chief operating officer.

Railtech Boutet has also been promoting its new QP Hybrid molds for the past six months. These molds have a ceramic felt lining on the current mold design, which Dolder says virtually eliminates flashing along the web and base of the rail, resulting in a cleaner, better weld.

"The response from our customers on this product has been extremely positive and a welcomed improvement for aluminothermic welding," said Dolder.

In addition to promoting Startwel and the QP molds, Railtech Boutet continues its study on high-carbon and high-strength rail.

"[The company] is designing a weld kit that is closer to the metallurgical properties of these types of special rails, which will accommodate our customers, which are currently using these types of rails in mainline track and/or tangents and curves," said Dolder.

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