SIST EN 14811:2007+A1:2010
(Main)Railway applications - Track - Special purpose rail - Grooved and associated construction
Railway applications - Track - Special purpose rail - Grooved and associated construction
This European Standard specifies requirements for grooved rails and associated construction rail profiles for grooved rail facilities with a linear mass of 42 kg/m and upwards for use in tram transport systems. NOTE Grooved rails are also used for harbour and industrial tracks.Six pearlitic steel grades are specified in a hardness range between 200 HBW and 390 HBW. The rails are either non-heat-treated or heat-treated and are made from non-alloyed (C-Mn) steel in both cases. This standard specifies 18 specific grooved rail profiles and 7 specific construction rail profiles. The grooved rail profiles can also be used as construction elements in switches and crossings. Two grooved rail classes are specified differing in requirements for profile tolerances.
Bahnanwendungen - Oberbau - Spezialschienen - Rillenschienen und zugehörige Konstruktionsprofile
Diese Europäische Norm legt Anforderungen für Rillenschienen und zugehörige Konstruktionsprofile für
Rillenschienen-Anlagen mit einer längenbezogenen Masse ab 42 kg/m für die Anwendung im Straßenbahnverkehr
fest.
ANMERKUNG Rillenschienen werden auch für Hafen- und Industriegleise verwendet.
Sechs perlitische Stahlsorten in einem Härtebereich zwischen 200 HBW und 390 HBW sind festgelegt. Die
Schienen sind entweder nicht wärmebehandelt oder wärmebehandelt und bestehen in beiden Fällen aus
unlegiertem (C-Mn) Stahl.
In dieser Norm sind 18 definierte Rillenschienenprofile und 7 definierte Konstruktionsprofile festgelegt. Die
Rillenschienenprofile können ebenso als Konstruktionselemente in Weichen und Kreuzungen verwendet
werden.
Zwei Rillenschienenklassen sind festgelegt, die sich hinsichtlich der Anforderungen an die Profiltoleranzen
unterscheiden.
Applications ferroviaires - Voie - Rails spéciaux - Rails à gorge et profils de construction associés
Železniške naprave - Zgornji ustroj - Specialne tirnice - Tirnice z žlebom in elementi za kretnice in križišča
Ta evropski standard določa zahteve za tirnice z žlebom in tirnične profile podobne konstrukcije za infrastrukturo tirnic z žlebom z linearno maso 42 kg/m in več, ki se uporablja pri tramvajskih prevoznih sistemih. OPOMBA: Tirnice z žlebom se uporabljajo tudi za pristaniške in industrijske tire. Določenih je šest vrst perlitnega jekla z razponom trdote med 200 HBW in 390 HBW. Tirnice so toplotno neobdelane ali obdelane in so v obeh primerih narejene iz nelegiranega (C-Mn) jekla. Ta standard določa 18 specifičnih profilov tirnic z žlebom in 7 specifičnih konstrukcijskih profilov tirnic. Profili tirnic z žlebom se lahko uporabljajo tudi kot konstrukcijski elementi pri kretnicah in križiščih. Določena sta dva razreda tirnic z žlebom, ki se razlikujeta glede na zahteve tolerance profila.
General Information
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Standards Content (Sample)
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Bahnanwendungen - Oberbau - Spezialschienen - Rillenschienen und zugehörige KonstruktionsprofileApplications ferroviaires - Voie - Rails spéciaux - Rails à gorge et profils de construction associésRailway applications - Track - Special purpose rail - Grooved and associated construction45.080Rails and railway componentsICS:Ta slovenski standard je istoveten z:EN 14811:2006+A1:2009SIST EN 14811:2007+A1:2010en,fr01-marec-2010SIST EN 14811:2007+A1:2010SLOVENSKI
STANDARD
SIST EN 14811:2007+A1:2010
EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM
EN 14811:2006+A1
November 2009 ICS 45.080; 93.100 Supersedes EN 14811:2006English Version
Railway applications - Track - Special purpose rail - Grooved and associated construction
Applications ferroviaires - Voie - Rails spéciaux - Rails à gorge et profils de construction associés
Bahnanwendungen - Oberbau - Spezialschienen - Rillenschienen und zugehörige Konstruktionsprofile This European Standard was approved by CEN on 2 June 2006 and includes Amendment 1 approved by CEN on 22 September 2009.
CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN Management Centre or to any CEN member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CEN member into its own language and notified to the CEN Management Centre has the same status as the official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre:
Avenue Marnix 17,
B-1000 Brussels © 2009 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 14811:2006+A1:2009: ESIST EN 14811:2007+A1:2010
EN 14811:2006+A1:2009 (E) 2 Contents Page Foreword .3 Introduction .4 1 Scope .6 2 Normative references .6 3 Terms and definitions .6 4 Information to be supplied by the purchaser .7 5 Steel grades .7 6 Dimensions, static properties, linear mass and tolerances .8 7 Manufacture .8 7.1 Product integrity .8 7.1.1 Factory production control .8 7.1.2 Best practice manufacture .8 7.2 Blooms .9 7.3 Grooved rails and associated construction rail profiles .9 7.4 Marking .9 7.4.1 Rolling marks .9 7.4.2 Hot stamping . 10 7.4.3 Other identification . 11 7.4.4 Exceptions . 11 8 Acceptance tests . 11 8.1 Laboratory tests . 11 8.1.1 General . 11 8.1.2 Chemical composition . 11 8.1.3 Hydrogen . 13 8.1.4 Hardness test . 13 8.1.5 Tensile test . 14 8.1.6 Retests . 14 8.2 Dimensional and straightness tolerances . 14 8.2.1 Profile . 14 8.2.2 Straightness and twist . 17 8.2.3 Cutting and drilling . 17 8.2.4 Gauges . 18 8.3 Surface imperfections . 18 8.3.1 General . 18 8.3.2 Protrusions . 18 8.3.3 Depressions in the web and foot . 19 8.3.4 Depressions in the running surface . 19 8.4 Surface microstructural damage . 19 8.5 Proving and dressing of surface imperfections . 19 8.6 Determination of the linear mass . 20 Annex A (normative)
Grooved rail profiles and associated construction rail profiles . 23 Annex B (normative)
Gauges . 50 Annex C (informative)
Holes in grooved rails . 63 Annex D (informative)
Electric repair welding and electric conductivity of the rails . 65 Bibliography . 66 SIST EN 14811:2007+A1:2010
EN 14811:2006+A1:2009 (E) 3 Foreword This document (EN 14811:2006+A1:2009) has been prepared by Technical Committee CEN/TC 256 “Railway applications”, the secretariat of which is held by DIN. This document shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by May 2010, and conflicting national standards shall be withdrawn at the latest by May 2010. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights. This document includes Amendment 1, approved by CEN on 2009-09-22. This document supersedes EN 14811:2006. The start and finish of text introduced or altered by amendment is indicated in the text by tags !". Other standards on rails include: EN 13674 Railway applications — Track — Rail that comprises the following parts: Part 1: Vignole railway rails 46 kg/m and above Part 2: Switch and crossing rails used in conjunction with Vignole railway rails 46 kg/m and above
Part 3: Check rails Part 4: Vignole railway rails from 27 kg/m to 46 kg/m. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. SIST EN 14811:2007+A1:2010
EN 14811:2006+A1:2009 (E) 4
Introduction This introduction provides an explanation of the concept and reasoning for preparing this standard. Its description ensures that, during any future revisions, restrictions will be removed if technical progress has been made or will be kept if this is not the case in order that safety is maintained if new manufacturers, products and technologies appear. The most commonly used delivery conditions in Europe for the supply of grooved rails and associated construction rail profiles have been reviewed during the preparation of this standard. Modern rail production technology and the requirements of commuter railways within the European Union have demanded that the technical requirements for the products specified in EN 14811 be reconsidered. Whenever possible, this EN 14811 is performance-based. It recognizes the European quality management standard EN ISO 9001 and requires manufacturers to offer the latest proven technology consistently to satisfy the demanding quality of the required product. The steels are classified according to hardness and not to tensile strength. The acceptance tests were developed in order to monitor the properties of the grooved rail steels and grooved rails and associated construction rail profiles that are of importance for the production of grooved rails and associated construction rail profiles and which comply with the demands of commuter railways. The steel grades covered by EN 14811 reflect trends in commuter railway usage and heat-treated rails as well as associated construction rail profiles. This standard contains profiles for grooved rails and associated construction rail profiles for grooved rail facilities having a linear mass of 42 kg/m and above. To ensure the supply of high quality rails, some restrictions on production processes have been imposed. This standard is applicable to all procurements covered by the European Procurement Directive (93/38/EEC of 14 June 1993). Additionally, CEN has requested a performance-based standard taking into account safety requirements and the application of the most recent technologies. With respect to the Directive, it is acknowledged that there are (and with respect to safety requirements also shall be) options to deviate from the standard upon agreement between purchaser and manufacturer.
This standard reflects the change in philosophy compared with the traditional content of delivery conditions for grooved rails and associated construction rail profiles. The most frequently used delivery conditions in Europe for the supply of grooved rails and construction rail profiles have been reviewed. All the aspects that are important for the purchasers and manufacturers have been analysed to ensure that the overall contents are particularly appropriate and relevant for the European Standard. For example, the classification of the steel grades of grooved rails and associated construction rail profiles and also other aspects of the European Standard has been based on hardness, not on tensile testing. Whilst the two are directly related, hardness testing is very quick and inexpensive to carry out and provides more relevant guidance to the user, particularly where properties vary in different parts of the profile. One new aspect of the European Standard is the integration of a clause on quality management and testing in order to assure the product integrity. In order to ensure that the quality management systems are consistent for all manufacturers and that all purchasers can be sure about the consistency of the product quality of these safety-related components, this standard recommends that the manufacturer operates a quality management system at least equivalent to the requirements of EN ISO 9001. This makes it possible to dispense with detailed requirements on tests and comprehensive testing. SIST EN 14811:2007+A1:2010
EN 14811:2006+A1:2009 (E) 5 Ideally, manufacturing methods should not be referred to in product standards. However, some rail properties are either not exactly known or cannot be determined with an adequately high statistical reliability. In these cases, as the final possibility, reference is made to manufacturing methods that correspond to best practice. Methods and requirements are specified that offer the maximum probability that the necessary product is obtained in the track. Future technological solutions can increase the list of these requirements but will preferably reduce them. Examples of where today's technology is taken as the basis, but developments are progressing, are: determination of hydrogen content; minimum area reduction for rolling of grooved rails and associated construction rail profiles; roller straightening effects on contact scrub. SIST EN 14811:2007+A1:2010
EN 14811:2006+A1:2009 (E) 6 1 Scope This European Standard specifies requirements for grooved rails and associated construction rail profiles for grooved rail facilities with a linear mass of 42 kg/m and upwards for use in tram transport systems. NOTE Grooved rails are also used for harbour and industrial tracks. Six pearlitic steel grades are specified in a hardness range between 200 HBW and 390 HBW. The rails are either non-heat-treated or heat-treated and are made from non-alloyed (C-Mn) steel in both cases. This standard specifies 18 specific grooved rail profiles and 7 specific construction rail profiles. The grooved rail profiles can also be used as construction elements in switches and crossings. Two grooved rail classes are specified differing in requirements for profile tolerances. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. !deleted text" EN 10027-1, Designation systems for steel — Part 1: Steel names EN 10027-2, Designation systems for steel — Part 2: Steel numbers EN ISO 6506-1, Metallic materials — Brinell hardness test — Part 1: Test method (ISO 6506-1:2005) !EN ISO 6892-1, Metallic materials - Tensile testing - Part 1: Method of test at room temperature (ISO 6892-1:2009)" 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 heat liquid steel melt tapped out of a converter or electric arc furnace which after continuous casting includes a given number of blooms relating to the weight of the heat and the extent of the mixing zone. In the case of sequence casting, the blooms belonging to the mixing zone are to be clearly defined 3.2 sequence number of heats of the same steel grade which undergo continuous casting in a new or repaired tundish. Tundishes may be used in parallel if the caster has many strands 3.3 heat-treated rail rail that has undergone accelerated cooling from austenitizing temperature during the metallurgical transformation period 3.4 head-hardened grooved rail grooved rail where the rail head and/or the grooved head has been heat-treated SIST EN 14811:2007+A1:2010
EN 14811:2006+A1:2009 (E) 7 3.5 construction rail profile rail used in switches and crossings which carries the wheel NOTE Grooved rail profiles can also be used as construction elements in switches and crossings. 3.6 grooved head that part of the profile that provides the space for the wheel flange. It is also used as the supporting element for the pavement NOTE The term “grooved head” has been introduced instead of “guiding head”, “guiding rail” and other similar terms. 3.7 rolling bead protuberance that is formed at the roll gap during rolling 4 Information to be supplied by the purchaser The purchaser shall provide the following information at the time of tender or order: a) the rail profile (see annex A); b) the steel grade (see clause 5); c) the individual length or individual lengths of the rails. Unless otherwise agreed, short lengths shall be supplied in pairs and they shall not be less than half the individual length of the rails; also, the total mass of the short lengths shall not exceed 10 % of the total mass of the order; d) the location and dimensions of holes (see Annex C); e) paint code requirements (see 7.4.3). 5 Steel grades The applicable steel grades are given in Table 1. The hardness ranges shall meet the requirements in Table 1. For the steel grades in Table 1, the steel names in accordance with EN 10027-1 and the steel numbers in accordance with EN 10027-2 shall be used. Other requirements that can be agreed between the manufacturer and the purchaser are given in Annex D.
SIST EN 14811:2007+A1:2010
EN 14811:2006+A1:2009 (E) 8 Table 1 — Steel grades Stahl grade a Hardness range in HBW Description Type of rolling markSteel name Material number R200 1.0521 200 to 240 Non-alloyed (C-Mn)-steel No rolling marks R220G1 1.0604 220 to 260 Non-alloyed (C-Mn)-steel ——— R260 1.0623 260 to 300 Non-alloyed (C-Mn)-steel —— ———- R260GHT 1.0636 260 to 300 Non-alloyed (C-Mn)-steel, head- hardened —— —— ——— R290GHT 1.0637 290 to 330 Non-alloyed (C-Mn)-steel, head- hardened ——— ——— R340GHT 1.0638 340 to 390 Non-alloyed (C-Mn)-steel, head- hardened
—— ——— ——— a See Tables 3a and 3b for the chemical composition and the mechanical properties.
6 Dimensions, static properties, linear mass and tolerances The requirements for the profile drawings, their dimensions, static properties and linear mass are given in Annex A. The tolerances of certain dimensions shall be as given in Tables 5a and 5b. All other quantities are informative only. NOTE Linear masses have been calculated based on a density of steel of 7,85 kg/dm3. 7 Manufacture 7.1 Product integrity 7.1.1 Factory production control All grooved rails and associated construction rail profiles shall be produced under a comprehensive system of production control in order to ensure confidence in the conformity of the finished product. The system shall address this European Standard to ensure that the finished products consistently comply with requirements to achieve the product integrity necessary to provide assurance of product safety in track. The manufacturer shall demonstrate by documented evidence continuing compliance with the factory production control system required. Manufacturers having a factory production control system which complies with EN ISO 9001 shall be recognized as satisfying the minimum requirements specified by this clause. 7.1.2 Best practice manufacture The product shall be manufactured to the best practices as defined in 7.1.1. NOTE This is to ensure that the rail attributes, described in the introduction, which are not known in an exact manner or are not practically measurable, achieve the required high level of product integrity in track. SIST EN 14811:2007+A1:2010
EN 14811:2006+A1:2009 (E) 9 7.2 Blooms 7.2.1 Basic oxygen steel or electric arc furnace steel shall be used for the manufacture of grooved rails and associated construction rail profiles. In the case of electric arc steel, a secondary ladle arc refining facility shall be used. 7.2.2 Steels for head-hardened grooved rails shall be vacuum-degassed. 7.2.3 Only continuously-cast materials shall be used for manufacturing of blooms. 7.3 Grooved rails and associated construction rail profiles 7.3.1 The rail manufacturing process used is at the discretion of the manufacturer. If the purchaser so requests, however, he shall indicate the method and main characteristics. The manufacturer shall not change these without informing the purchaser beforehand. 7.3.2 The scale shall be removed by means of highly-pressurized water between the removal of the blooms from the heating furnace and the last pass in order to minimize surface damage and roughness. 7.3.3 If the linear mass of the profile is less than 110 kg/m, the original cross-section of the
continuously-cast bloom shall be at least 8 times greater than that of the rail profile to be rolled. An exception applies for the profile 105C1 where the original cross-section of the continuously-cast bloom shall be at least 7,5 times greater than that of the rail profile to be rolled. For heavier profiles (construction rails), the original cross-section shall be at least 2,5 times greater than that of the rail profile to be rolled. NOTE In this case, suitability for a heat treatment may be limited. 7.3.4 The straightening of the rails shall be done in a two-step roller-straightening process that straightens the rails about the axes x-x and y-y described in Annex A. Straightening presses may be used for end straightening or for correcting locally limited deviations from straightness. The rolled marking shall be protected from the effect of the straightening rolls. 7.3.5 Dividing into finished lengths shall be carried out by cold-sawing. Other cutting methods may be applied, provided that the microstructure remains unchanged. Any burr shall be removed without resulting in any noticeable bevelling of the profile. 7.3.6 Fishplate holes in the web of the rail shall be made round with smooth walls and be deburred. 7.3.7 Tie bar holes shall be round or oval. Round holes shall be stamped or drilled, oval holes stamped or milled. The edges of tie bar holes shall not have any dangerous burrs. 7.3.8 Fundamentally, no rolling beads shall be present at the rail head, grooved head or outer edges of the foot. Exceptions may be agreed between the purchaser and the manufacturer, but the inside edge of the grooved head shall not be sharp. 7.4 Marking 7.4.1 Rolling marks The following rolling marks shall be rolled on the outside of the web (running head side) in relief at least 0,8 mm high and in characters that are clearly legible of between 15 mm and 20 mm: the identification of the mill; the last two figures of the year of manufacture; SIST EN 14811:2007+A1:2010
EN 14811:2006+A1:2009 (E) 10 the grooved rail or construction rail profile identification (see Tables A.1 and A.2); the symbol for the steel grade (see Table 1). Short lines shall be approximately half the length of the long lines. The position of the rolling mark is specified in Table 2. Other symbols or marks may be added if agreed between purchaser and manufacturer. Table 2 — Position of the rolling mark Grooved rails and associated construction rail profiles Distance H in Figure 1
in mm 52R1, 56R1, 61C1 68 51R1, 53R1 53 59R1, 59R2, 60R1, 60R2, 75C1, 76C1 78 57R1, 67R1 63 62R1, 62R2 78 55G1, 55G2 55 46G1 52 68G1 71 60R3, 63R1 81 105C1 65
7.4.2 Hot stamping Each rail shall be identified by a stamped mark consisting of a numerical and/or alphabetical code. The code shall allow the following information to be identified: the number of the heat from which the rail has been rolled; the number of the strand and the position of the bloom within this strand; the position of the rail in the bloom (A, B…. Y). The identification mark of the rail shall be stamped at least once by the manufacturer on one of the two sides of the web of the hot-rolled rail. The figures and letters shall be clearly legible and 16 mm high. The stamped characters shall have a flat or radius (1 mm to 1,5 mm radius) face with bevels at the side. The marks shall be on a 10° angle from the vertical and shall have rounded corners. The stamping shall be not greater than 1,0 mm deep along the centre of the web. The design of the characters shall be as shown in Figure 2. If the rail does not have any stamped mark, it shall be identified by means of a code made by rotary burr. NOTE The following division of the rails can result in more than one rail having the same identity.
SIST EN 14811:2007+A1:2010
EN 14811:2006+A1:2009 (E) 11 7.4.3 Other identification At the request of the purchaser, the rails can be marked with paint. The colour and position of these paint marks shall be specified by the purchaser. 7.4.4 Exceptions The requirements of 7.4.1 and 7.4.2 do not apply to construction rail profiles 310C1, 338C1 or 42C1. 8 Acceptance tests 8.1 Laboratory tests 8.1.1 General One laboratory test per heat shall be carried out. Results for each laboratory test shall comply with the limiting values given in Tables 3a and 3b. 8.1.2 Chemical composition The liquid chemical composition shall be determined for each heat. If the solid chemical composition is determined, it shall be determined at the point from which the samples were taken for the tensile test. The requirements for the chemical limits for liquid and solid are given in Tables 3a and 3b.
SIST EN 14811:2007+A1:2010
EN 14811:2006+A1:2009 (E) 12 Table 3a — Chemical composition and mechanical properties Steel designation Chemical composition for % by mass % by mass in 10-4
% (ppm) Tensile strength Rm MPa min. Elongation after fracture a A % min. Centre line running surface hardness HBW C Si Mn P max.
S max.
H max. R200
Liquid 0,40 to 0,60 0,15 to 0,58 0,70 to 1,20 0,035 0,035 3,0 680 14 200 to 240 Solid 0,38 to 0,62 0,13 to 0,60 0,65 to 1,25 0,040 0,040 3,0 R220G1 Liquid 0,50 to 0,65 0,15 to 0,58 1,00 to 1,25 0,025 0,025 3,0 780 12 220 to 260 Solid 0,48 to 0,67 0,13 to 0,60 0,95 to 1,30 0,030 0,030 3,0 R260 Liquid 0,62 to 0,80 0,15 to 0,58 0,70 to 1,20 0,025 0,025 2,5 880 10 260 to 300 Solid 0,60 to 0,82 0,13 to 0,60 0,65 to 1,25 0,030 0,030 2,5 R260GHT Liquid 0,40 to 0,60 0,15 to 0,58 0,70 to 1,20 0,035 0,035 2,5 880 12 260 to 300 Solid 0,38 to 0,62 0,13 to 0,60 0,65 to 1,25 0,040 0,040 2,5 R290GHT Liquid 0,50 to 0,65 0,15 to 0,58 1,00 to 1,25 0,025 0,025 2,5 960 10 290 to 330 Solid 0,48 to 0,67 0,13 to 0,60 0,95 to 1,30 0,030 0,030 2,5 R340GHT Liquid 0,62 to 0,80 0,15 to 0,58 0,70 to 1,20 0,025 0,025 2,5 1175 9 340 to 390 Solid 0,60 to 0,82 0,13 to 0,60 0,65 to 1,25 0,030 0,030 2,5 a The limiting values for elongation after fracture do not apply for heavy construction rails 310C1 and 338C1.
Table 3b — Maximum residual elements content in % by mass Cr Mo Al Cu Cu + 10Sn Cr + Mo + Ni + Cu + V 0,15 0,02 0,004 0,15 0,35 0,35
SIST EN 14811:2007+A1:2010
EN 14811:2006+A1:2009 (E) 13 8.1.3 Hydrogen The hydrogen content of the liquid steel shall be measured by determining the pressure of the hydrogen in the steel using an on-line immersion probe system. At least two samples shall be taken from the first heat of any sequence using a new tundish and one from each of the remaining heats and analysed for hydrogen content. The first sample from the first heat in a sequence shall be taken from the tundish at the time when the maximum hydrogen content is reached. If the hydrogen content is less then or equal to the values listed in Table 3a for the respective grades, the heat shall be deemed satisfactory. Blooms of heats where the determined hydrogen content is greater than the values listed in Table 3a shall be slowly cooled or isothermally treated. The test shall be performed on the finished rail for all heats. All blooms cast prior to sampling and all other blooms cas
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