Company Profile

Product Range

A number of welding processes, all utilising the alumino thermic reaction are available, and the appropriate process for a specific application is agreed with the customer prior to supply.

All the process use preformed refractory sand moulds which are available to fit a wide range of rail sections and for joining rails of differing sections. These moulds comprise either two or three pieces. Special moulds are available for working on unusual types of track support, for example continuous concrete slab track.

The Thermit® Welding powders are formulated to match the metallurgical and mechanical properties of the rails with which they will be used, and are supplied as a premixed and measured portion in a protective container.

Thermit Welding (GB) Ltd is a manufacturing company supplying the railway industry with products and equipment for the joining of rails using the alumino-thermic welding process, under the Thermit® registered trademark.

We are the principal supplier of alumino thermic rail welding materials to all the U.K railway administrations, however our process and products are used worldwide, and include High Speed, Heavy Rail, Mass Transit, Light Rail, Metro and Tram systems.

The company is an approved supplier to British Rail and has been successfully audited by Lloyds for approval to the European Quality Standard ISO 9002.

Company Background
Murex Ltd, in partnership with Elektro-Thermit GmbH, began manufacturing Alumino thermic products on its site in Rainham, Essex, in 1926, and subsequently Thermit Welding (GB) Ltd was formed to manufacture and supply the process. In 1978 the company moved into a new factory on an adjacent site, where it remains today. We are currently a subsidiary of Elektro-Thermit GmbH (which in turn forms part of the Th. Goldschmidt AG Group), but we operate as a totally independent company.

Thermit Welding (GB) Ltd, and our sister company, Thermitrex SA, employ approximately 80 staff. In addition we can call on the resources of both Elektro-Thermit GmbH and Th. Goldschmidt AG for technical support services.

Portions are available to suit many different rail steels, including:

B.S. 11:	All grades, Wear resistant Grade A and B
UIC - 860-0:	Grades A & B
AREA:	Grade 900A
British Steel PLC:	110 Kg/mm2 1% Cr, Conductor Rail Low Carbon Austenitic Manganese Steel Heat Treated Rails

Welding processes for conventional railway systems include the following:

The Thermit® SkV-F Process

The SkV-F process is the principal method used by British Rail for joining rails on site by welding. Since its introduction on BR in 1977, approximately 55,000 welds are made each year by this process, with a total population now in excess of 800,000. Welds can be manufactured on conventional ballasted, or on continuously supported track, and two or three piece moulds are available to fit a wide range of rail sections, and joints between rails of different section or wear. Its main features are:

• Welding Gap of 22-26 mm
• Short, timed preheat (1.5-2 mins, depending upon rail section)
• Full size Thermit® portion

The Thermit® SmW-F Process

Our SmW-F process is particularly suited to applications where a slightly longer operating time can be accepted, in which case a full preheat, with a smaller portion may yield benefits in terms of reduced costs. Two piece moulds are available for most of the common rail sections. Its main features are:

• Welding Gap of 20-22 mm
• Full preheat (4-7 mins, depending upon rail section)
• Reduced Size Thermit® portion

Thermit Welding on Docklands Light Railway

The Thermit® SoWoS Process

The SoWoS process combines the technical benefit of a timed preheat with the reduced consumable cost associated with a smaller portion. The process is used by British Rail for welding special quality steel components used in high speed or high axle load track, and has been selected for use in the Ankara Metro which is currently under construction. The key features are:

• Welding Gap of 22-24 mm
• Timed preheat of 3-6 mins depending on rail section
• Reduced size portion

The Thermit® Wide Gap Welding Processes

The company has developed two wide gap welding processes for use when the rail gap has to be wider than normal, as in the case of removal of a time expired weld or small rail defect. They may also be used to repair broken rails. The processes have been found to yield significant cost benefits compared with alternative methods for replacing broken rails. The weld exhibit excellent fatigue properties.

In both processes, the operating procedures have been developed to be as similar to the standard SkV-F process, thus minimising equipment purchase and welder training. Both processes are fully approved for use on BR. The principal features are:

• Rail gap 48-53 mm (SkV-L50), or 76-80 mm (SkV-L80)
• Short timed preheat (1.5-2 mins dependent on rail section)
• Standard types of Thermit® portion

For welding grooved, or heavy rails, two further methods are available:

The Thermit® SRZ Process

The SRZ process has been developed for welding the grooved rails used in many metro systems. The process uses a full preheat, dependent upon rail section, combined with a centre pour.

The Thermit® SkS Process

This process, which also uses a full preheat and central pour system, is designed for use with heavy section crane rails ranging from 56kg/m to 164kg/m. The moulds are usually three piece, and a reduced depth bottom collar can be incorporated for use on continuous support.

Automatic Crucible Tapping

In all our processes the Thermit® portion is charged and subsequently ignited in a reusable refractory crucible. When the resulting Thermit steel is at the correct temperature for casting, the Automatic Tapping thimble allows the steel to tap into the moulds. This system offers major advantages with respect to welder safety.

Quality

The Company's continued commitment to product quality has resulted in its approval to ISO 9002. All our suppliers are subject to a regular quality audit, and raw materials undergo stringent quality tests before use.

All our products are checked throughout the production process using a range of analytical methods, including chemical analysis by emission spectography, and mechanical testing (weld hardness and strength), and are identified such that they can be traced back through the various stages of manufacture and against quality records.

The Thermit® portion formulation is to internal specifications designed to produce a Thermit steel complying with the appropriate rail steel. Portions can be supplied to customer specifications such as the British Rail Specification No. 552 for alumino thermic powders or alternatively our own specifications for the Thermit Steel can be provided on request.

Welding procedures are available for all the processes, and may be adapted in liaison with the customer to suit their specific application, by means of procedural tests. Procedures are regularly reviewed and updated to incorporate the latest developments, with particular attention to safety and quality.

Selection of Thermit® Welding Consumables

Research and Development

Thermit Welding (GB) liaises closely with its customers, and railway authorities, to develop welding procedures, materials and processes, and we have representatives on committees preparing international standards for welding and welding products. Membership of, and access to Research and Technical organisations such as British Rail Research, The Welding Institute, PERA, BCIRA, ensure that new technology can be incorporated into the production and use of the Thermit Welding processes.

All our processes, consumable and equipment have been subjected to extensive procedural trials before they are offered to customers. Our process development programmes have included fatigue and fracture toughness testing, metallurgical, chemical and mechanical examination, non destructive testing, followed by clinical field testing, and reliability studies.

Manufacturing Capability

The pre-formed moulds are designed and manufactured within the company for a wide range of rail sections. Mould patterns can be designed to suit unusual rail sections, or they may be obtained through the Thermit Group. In excess of 90,000 sets of moulds are produced each year.

Iron oxide is refined for the portions and then graded and mixed with the other raw materials, which are principally aluminium, ferro-manganese, steel and alloying additions. Each portion is individually mixed and weighed into waterproof containers and identified by batch, weight and grade of powder. The plant manufactures and processes over 80,000 kg of Thermit® powder each year.

We provide the complete range of equipment required for the manufacture of Thermit welds in track, including items of plant such as rail saws, hydraulic weld trimmers, and rail grinding equipment. Some items are manufactured off site by a small number of approved suppliers, but all are supplied to us for Quality Assurance inspection before being offered for sale. Our product range has in excess of 1200 items, the majority of which are held in stock, available for prompt delivery.

After Sales Support

Operator Training Courses and examination can be provided, either here at Rainham, or on the customer's site. Service engineers are available to provide support during field trials and deal with any technical problems.

Track Thermit® Welded on Singapore MRT

Notre gamme de Produits

Plusieurs procédés de soudure, utilisant tous la réaction aluminothermique, sont disponibles et avant d'envoyer le matériel, nous choisissons avec le client le procédé qui convient pour une application spécifique.

Tous les procédés utilisent des moules préformés en sable réfractaire, qui sont disponibles dans un grand nombre de modèles pour une large gamme de sections de rails, ainsi que pour joindre des rails de différentes sections. Ces moules sont constitués de deux ou trois pièces. II existe également des moules spéciaux pour les travaux sur des renforts de voies peu courants, comme par exemple les voies en blocs de béton continus.

Les poudres de soudure Thermit® sont formulées afin de s'accorder aux propriétés métallurgiques et mécaniques des rails pour lesquels elles seront utilisées; elles se présenteent sous la forme de portions pré-mélangées et mesurées, en conteneurs de protection. Plusieurs portions sont disponibles, pour s'adapter à une grande variété d'aciers de rails, dont:

Safety

Safety sheets and transport information is available on request for the portions and igniters. Instructions for Welder safety are included in our welding procedures and training course and advice can be provided as to the correct protective clothing, goggles etc. All welding staff would be expected to have attended an appropriate training course and should be certificated, either by the company or an authorised examiner, in the relevant processes.

Profil de la société - ses produits

Introduction

Thermit Welding (GB) Ltd est une société manufacturière fournissant à l'industrie ferroviaire les produits et le matériel servant à joindre les rails grâce à ;'utilisation du procédé de soudure aluminothermique ("thrmite"), souse la marque déposée Thermit®. Nouse sommes les principaux fournisseurs de matériels aluminothermiques de soudure de rail de toutes les administrations de chemin de fer britanniques; mais notre procédé et nos produits sont utilisés dans le monde entier et comprennent les systèmes pour lignes à grande vitesse, pour artère à gros trafic, mass transit (le transport collectif), ligne facile, le métro et le tramway. Notre société est fournisseur agréé de British Rail et a récemment fait l'objet avec succès d'un audit de la Lloyds pour accréditation à ISO 9002.

Thermit Welding (GB) Ltd et sa société soeur Thermitrex SA, emploient environ 90 personnes. La société peut en outre faire appel aux ressources des deux sociétés Elektro-Thermit GmbH et Th. Goldschmidt AG pour les services de soutien technique.

Histoire de la Société

Thermit Welding (GB) Ltd, formée en partenariat par la société Murex Ltd et Elektro Thermit GmbH, commence à manufacturer les produits Aluminothermiques en 1926, à l'usine Murex de Rainham, dans l'Essex. En 1978, la société emménage dans une nouvelle usine, sur un terrain adjacent, où elle se trouve encore aujourd'hui. Nous sommes actuellement l'une des filiales d'Elektro-Thermit GmbH (qui fait elle-même partie du groupe Th. Goldschmidt AG) mais nous opérons comme une société totalement indépendante.

Contact: Mr R S Johnson
General Manager - Technical Sales