SIST EN 13411-4:2011
(Main)Terminations for steel wire ropes - Safety - Part 4: Metal resin socketing
Terminations for steel wire ropes - Safety - Part 4: Metal resin socketing
This European Standard specifies the minimum requirements for the molten metal and resin socketing of steel wire ropes within the scopes of EN 12385-4:2002+A1:2008; EN 12385-5:2002; EN 12385-6:2004; EN 12385-7:2002; EN 12385-8:2002; EN 12385-9:2002 and EN 12385-10:2003+A1:2008. The European Standard is applicable only to those requirements that ensure that the socketing is strong enough to withstand a force of at least 100 % of the minimum breaking force of the rope (i.e. socket termination efficiency factor KT = 1,0). Socketing by the methods and materials described in this standard are for use within the temperature limits given in normative Annex E. This European Standard deals with all significant hazards, hazardous situations and events relevant to metal and resin socket terminations, when they are used as intended and under conditions of misuse which are reasonably foreseeable (see Clause 4). This second edition incorporates both technical and editorial amendments, with the following main changes made with respect to the previous edition: - enhance approved socket dimension criteria negating need for type testing and move data into informative Annex F; - add definition for ‘socketing manufacturer’; - re-draft hazards clause; - re-draft standard in accordance with rules of ISO/IEC Directives, Part 2 and CEN Guide 414.
Endverbindungen für Drahtseile aus Stahldraht - Sicherheit - Teil 4: Vergießen mit Metall und Kunstharz
Diese Europäische Norm legt die Mindestanforderungen für das Vergießen von Drahtseilen aus Stahldraht mit geschmolzenem Metall und Kunstharz, nach EN 12385–4:2002+A1:2008; EN 12385–5:2002; EN 12385–6: 2004; EN 12385–7:2002; EN 12385–8:2002; EN 12385–9:2002 und EN 12385–10:2003 +A1:2008, fest.
Diese Europäische Norm ist nur für solche Anforderungen anwendbar, die sicherstellen, dass der Verguss fest genug ist, um einer Kraft von mindestens 100 % der Mindestbruchkraft des Seiles zu widerstehen (d.h. Wirkungsgradfaktor der Endverbindung der Seilhülse KT = 1,0).
ANMERKUNG Seilendverbindungen durch Vergüsse nach dieser Europäischen Norm können verwendet werden, um die Bruchkraft von Drahtseilen nach EN 12385-1:2002+A1:2008, Anhang A, zu bestimmen.
Vergüsse, die nach und mit den in dieser Norm beschriebenen Verfahren und Werkstoffen hergestellt sind, sind für Anwendungen innerhalb der im normativen Anhang E angegebenen Temperaturgrenzen geeignet.
Diese Europäische Norm befasst sich mit allen signifikanten Gefährdungen, gefährlichen Situationen und relevanten Ereignissen für das Vergießen von Metall- und Kunstharz-Endverbindungen, wie sie bei vorgesehenem Gebrauch entstehen oder durch Fehlanwendungen und die vernünftig absehbar waren. (siehe Abschnitt 4).
Terminaisons pour câbles en acier - Sécurité - Partie 4: Manchonnage à l'aide de métal ou résine
La présente Norme européenne spécifie les prescriptions minimales pour le manchonnage à l'aide de métal fondu et de résine des câbles en acier conformément à l'EN 12385, parties 4 à 10.
La présente norme couvre uniquement les prescriptions assurant que le manchonnage est suffisamment résistant pour supporter une charge au moins égale à 100 % de la charge minimale de rupture du câble (c'est-à-dire un facteur d'efficacité de la terminaison manchonnée KT = 1,0).
NOTE Les terminaisons de câbles réalisées par manchonnage conformément à la présente Norme européenne peuvent être utilisées pour déterminer la charge de rupture des câbles en acier conformément à l'Annexe A de l'EN 12385-1:2002.
Le manchonnage effectué selon les méthodes et à l'aide des matériaux décrits dans la présente norme est destiné à être utilisé dans les limites de température données dans l'Annexe E informative.
Les phénomènes dangereux couverts par la présente Norme européenne sont identifiés à l'Article 4.
Zaključki jeklenih žičnih vrvi - Varnost - 4. del: Zalivke iz kovin in umetnih smol
Ta evropski standard določa minimalne zahteve za taljene zalivke iz kovin in umetnih smol za jeklene žične vrvi v okviru EN 12385-4:2002+A1:2008; EN 12385-5:2002; EN 12385-6:2004; EN 12385-7:2002; EN 12385-8:2002; EN 12385-9:2002 in EN 12385-10:2003+A1:2008. Ta evropski standard se uporablja le za zahteve, ki zagotavljajo, da so zalivke dovolj močne, da prenesejo silo, ki ustreza najmanj 100 % minimalne pretržne sile vrvi (tj. faktor učinkovitosti zaključka zalivke KT = 1,0). Zalivke po metodah in materialih, opisanih v tem standardu, so za uporabo v temperaturnih omejitvah, podanih v normativnem dodatku E. Ta evropski standard obravnava velike nevarnosti, nevarne situacije in primere, ki se nanašajo na zaključke zalivk iz kovin in umetnih smol, kadar se uporabljajo, kot je predvideno in v okoliščinah napačne uporabe, ki se lahko razumno predvidijo (glej točko 4). Ta druga izdaja zajema tehnična in redakcijska dopolnila z naslednjimi glavnimi spremembami glede na prejšnjo izdajo: – poudarja odobrena merila za dimenzije zalivk, ki preklicujejo potrebo po tipskem preskušanju, in premik podatkov v informativni dodatek F; – dodana definicija za »proizvajalca zalivk«; – na novo oblikovana točka o nevarnostih; – na novo oblikovan standard v skladu s pravili direktiv ISO/IEC, 2. del, in Vodilom CEN 414.
General Information
Relations
Standards Content (Sample)
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Endverbindungen für Drahtseile aus Stahldraht - Sicherheit - Teil 4: Vergießen mit Metall und KunstharzTerminaisons pour câbles en acier - Sécurité - Partie 4: Manchonnage à l'aide de métal ou résineTerminations for steel wire ropes - Safety - Part 4: Metal resin socketing77.140.99Drugi železni in jekleni izdelkiOther iron and steel products53.020.30Pribor za dvigalno opremoAccessories for lifting equipmentICS:Ta slovenski standard je istoveten z:EN 13411-4:2011SIST EN 13411-4:2011en,fr,de01-julij-2011SIST EN 13411-4:2011SLOVENSKI
STANDARDSIST EN 13411-4:2002+A1:20081DGRPHãþD
SIST EN 13411-4:2011
EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM
EN 13411-4
March 2011 ICS 77.140.99 Supersedes EN 13411-4:2002+A1:2008English Version
Terminations for steel wire ropes - Safety - Part 4: Metal and resin socketing
Terminaisons pour câbles en acier - Sécurité - Partie 4: Manchonnage à l'aide de métal et de résine
Endverbindungen für Drahtseile aus Stahldraht -Sicherheit - Teil 4: Vergießen mit Metall und Kunstharz This European Standard was approved by CEN on 19 February 2011.
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-CENELEC 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-CENELEC Management Centre has the same status as the official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, 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 © 2011 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 13411-4:2011: ESIST EN 13411-4:2011
EN 13411-4:2011 (E) 2 Contents Page Foreword .4Introduction .51Scope .62Normative references .63Terms and definitions .64List of significant hazards .85Safety requirements and/or protective measures .95.1General .95.2Preparation of rope and socket .95.2.1General .95.2.2Length marking of rope .95.2.3Serving .95.2.4Cutting of rope .95.2.5Cleanliness of socket . 105.2.6Inserting rope into socket . 105.2.7Opening the brush . 105.2.8Pre-treatment of the brush . 115.2.9Hooking . 115.2.10Positioning and alignment of brush, rope and socket. 115.2.11Sealing . 125.3Socketing . 125.3.1General . 125.3.2Molten metal socketing . 125.3.3Resin socketing . 135.4Removal of sealing material . 145.5Protection . 145.6Type testing . 146Verification of the safety requirements and/or measures . 146.1Length marking of rope . 146.2Serving . 146.3Cleanliness of socket . 146.4Opening the brush . 146.5Degreasing the brush . 146.6Hooking . 156.7Positioning and alignment of brush, rope and socket. 156.8Pre-heating the socket . 156.9Melting the metal. 156.10Pouring the metal. 156.11Cooling . 156.12Pouring the resin . 156.13Curing of the resin . 156.14Removal of sealing . 156.15After completion of the socketing. 157Information for use . 167.1General . 167.2Marking . 167.3Socketing manufacturer’s certificate. 16SIST EN 13411-4:2011
EN 13411-4:2011 (E) 3 Annex A (normative)
Molten metal socketing media . 17A.1Lead-based alloys . 17A.2Zinc . 17A.3Zinc-based alloy . 17Annex B (normative)
Resin socketing media . 18B.1General . 18B.2Physical properties . 18Annex C (normative)
Type testing for assessment of molten metal or resin socketed termination . 19C.1General . 19C.2Method of test . 19C.3Acceptance criteria . 19C.4Test report . 19Annex D (informative)
Procedure for pre-treatment of bright rope for improved adhesion when socketing with lead-based alloys . 20D.1General . 20D.2Fluxing . 20D.3Coating . 20Annex E (normative)
Operating temperature limits . 21Annex F (informative)
Approved socket design parameters . 22Annex ZA (informative)
Relationship between this European Standard And the Essential Requirements of EU Directive 2006/42/EC . 23Bibliography . 24 SIST EN 13411-4:2011
EN 13411-4:2011 (E) 4 Foreword This document (EN 13411-4:2011) has been prepared by Technical Committee CEN/TC 168 “Chains, ropes, webbing, slings and accessories - Safety”, the secretariat of which is held by BSI. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by September 2011, and conflicting national standards shall be withdrawn at the latest by September 2011. 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 supersedes EN 13411-4:2002+A1:2008. This document has been prepared under a mandate given to CEN by the European Commission and the European Free Trade Association, and supports essential requirements of EU Directive(s). For relationship with EU Directive(s), see informative Annex ZA, which is an integral part of this document. This second edition incorporates both technical and editorial amendments, with the following main changes made with respect to the previous edition: − enhance approved socket dimension criteria negating need for type testing and move data into informative Annex F; − add definition for ‘socketing manufacturer’; − re-draft hazards clause; − re-draft standard in accordance with rules of ISO/IEC Directives, Part 2 and CEN Guide 414. EN 13411, under the general title “Terminations for steel wire ropes Safety”, consists of the following parts: − Part 1: Thimbles for steel wire rope slings; − Part 2: Splicing of eyes for wire rope slings; − Part 3: Ferrules and ferrule-securing; − Part 4: Metal and resin socketing; − Part 5: U-bolt wire rope grips; − Part 6: Asymmetric wedge socket; − Part 7: Symmetric wedge socket; − Part 8: Swage terminals and swaging. 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, Croatia, 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 13411-4:2011
EN 13411-4:2011 (E) 5 Introduction This European Standard is a type C standard as stated in EN ISO 12100. The machinery concerned and the extent to which hazards, hazardous situations and events are covered are indicated in the scope of this standard. When provisions of this type C standard are different from those which are stated in type B standards, the provisions of this type C standard take precedence over the provisions of the other standards, for machines that have been designed and built according to the provisions of this type C standard. The methods of socketing described in this standard are based on established procedures and following them is considered to result in a rope termination having an efficiency of 100 % based on the minimum breaking force of the rope. It is assumed that the socket is: suitable for heating without changing the characteristics of the socket material when the socketing medium is molten metal; strong enough for the rope; and suitable for the purpose for which it is intended. SIST EN 13411-4:2011
EN 13411-4:2011 (E) 6 1 Scope This European Standard specifies the minimum requirements for the molten metal and resin socketing of steel wire ropes within the scopes of EN 12385-4:2002+A1:2008; EN 12385-5:2002; EN 12385-6:2004;
EN 12385-7:2002; EN 12385-8:2002; EN 12385-9:2002 and EN 12385-10:2003+A1:2008.
The European Standard is applicable only to those requirements that ensure that the socketing is strong enough to withstand a force of at least 100 % of the minimum breaking force of the rope (i.e. socket termination efficiency factor KT = 1,0). NOTE Rope terminations made by socketing in accordance with this European Standard can be used for determining the breaking force of wire ropes in accordance with EN 12385-1:2002+A1:2008, Annex A. Socketing by the methods and materials described in this standard are for use within the temperature limits given in normative Annex E. This European Standard deals with all significant hazards, hazardous situations and events relevant to metal and resin socket terminations, when they are used as intended and under conditions of misuse which are reasonably foreseeable (see Clause 4). 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. EN 59, Glass reinforced plastics Measurement of hardness by means of a Barcol impressor EN 1774:1997, Zinc and zinc alloys Alloys for foundry purposes Ingot and liquid EN 12385-1:2002+A1:2008, Steel wire ropes Safety Part 1: General requirements EN 12385-2:2002+A1:2008, Steel wire ropes Safety Part 2: Definitions, designation and classification EN ISO 75-2:2004, Plastics Determination of temperature of deflection under load Part 2: Plastics, ebonite and long-fibre-reinforced composites (ISO 75-2:2004) EN ISO 604, Plastics Determination of compressive properties (ISO 604:2002) EN ISO 3838, Crude petroleum and liquid or solid petroleum products Determination of density or relative density Capillary-stoppered pyknometer and graduated bicapillary pyknometer methods (ISO 3838:2004) EN ISO 12100:2010 Safety of machinery General principles for design Risk assessment and risk reduction (ISO 12100:2010) 3 Terms and definitions For the purpose of this document, the terms and definitions given in EN ISO 12100,
EN 12385-2:2002+A1:2008 and the following apply.
3.1 socket type of wire rope termination incorporating a socket basket SIST EN 13411-4:2011
EN 13411-4:2011 (E) 7 3.2 socket basket area of a socket in which a brushed rope end is secured using a socketing medium NOTE
Descriptions of further elements of the socket geometry are shown in Figure 1.
Key 1 length of tapered basket plus any parallel portion(s) including any radius at rope entry 2 small end of tapered basket 3 large end of tapered basket 4 included angle of tapered basket 5 bore (internal diameter at rope entry) 6 pin hole centre line 7 length of tapered basket 8 length of parallel portion including any radius at rope entry 9 protruding wires 10 length of brush 11 root of brush
NOTE Some sockets can have baskets with an extended parallel portion at the large end of the tapered basket. Figure 1 — Nomenclature of typical parts of socket and brush 3.3 serving wrapping, usually of wire or strand, for the purpose of securing a rope end to prevent its unlaying 3.4 permanent serving serving applied prior to socketing and remaining in place at least until the socketing operation has been completed 3.5 temporary serving serving applied and subsequently removed at various stages of the socketing operation 3.6 gelling change in condition of resin from liquid to a semi-solid, jelly-like composition 3.7 hooking procedure whereby the end of a wire forming part of a brush is bent backwards to form a hook SIST EN 13411-4:2011
EN 13411-4:2011 (E) 8 3.8 socketer competent person carrying out the socketing 3.9 competent person designated person, suitably trained, qualified by knowledge and experience and with the necessary instructions to ensure that the required operations are correctly carried out 3.10 socketing system method of attachment comprising instructions and materials for the socketing of wire ropes with molten metal or resin
3.11 socketing system designer person or organization that designs the socketing system and assumes responsibility for type testing 3.12 socketing manufacturer person or organization that manufactures socketed terminations in accordance with the socketing system designer’s instructions 4 List of significant hazards This clause contains all the significant hazards, hazardous situations and events for the molten metal and resin socketing of steel wire ropes within the scopes of EN 12385-4:2002+A1:2008; EN 12385-5:2002;
EN 12385-6:2004; EN 12385-7:2002; EN 12385-8:2002; EN 12385-9:2002 and EN 12385-10:2003+A1:2008, as far as these hazards are dealt with in this European Standard, identified by risk assessment as significant for socket terminations that require action to eliminate or reduce risk. In particular, the hazard caused by accidental release of a load due to failure of the socketed portion of a socketed rope termination puts at risk, either directly or indirectly, the safety or health of those persons within the danger zone. In order to provide the necessary strength of the socketed portion of a socketed termination, this European Standard gives requirements for the method of socketing to ensure specified levels of performance are met.
Table 1 contains those hazards that require action to reduce risk identified by risk assessment as being specific and significant for socketed termination assemblies.
Table 1 Hazards identified EN ISO 14121-1:2007, A.1 and A.4 Type or group OriginPotential consequences Mechanical hazards
- Acceleration, deceleration (kinetic energy) - Falling objects - Moving elements - Impact - Crushing
Hazardous events - Stability of the machine and/or parts of the machine - Mechanical strength of parts of - Loss of stability - Break-up during SIST EN 13411-4:2011
EN 13411-4:2011 (E) 9 the machine operation
5 Safety requirements and/or protective measures 5.1 General Machinery shall comply with the safety requirements and/or protective measures of this clause. In addition, the machine (rope assembly terminated in accordance with this European Standard and which is designated for lifting purposes) shall be designed in accordance with the principles of EN ISO 12100 for relevant but not significant hazards which are not dealt with by this document. Socketing shall be carried out by a person trained in socketing. 5.2 Preparation of rope and socket 5.2.1 General The position of the wires and strands of the non-socketed portion of rope shall remain undisturbed during the socketing operation. Temporary servings or, alternatively, a mechanical device e.g. clamp(s), may be used for this purpose. 5.2.2 Length marking of rope The rope shall be marked with the required length taking into account the length of the socket basket, the length of the brush to be formed, any additional brush length for the hooking of wires and, if used, the depth of any centralizing clamp. 5.2.3 Serving Temporary servings shall be used to hold the strands and wires in position during the cutting operation. Temporary servings shall also be used, when required by nature of the rope construction e.g. spiral rope, to maintain the lay of the rope etc. beyond the portion being socketed. The rope shall be served with a permanent serving as shown in Figure 2. The permanent serving shall be in position before cutting the rope. Unless specified otherwise by the socket manufacturer, the serving shall allow for penetration of the socketing medium between the served rope and the bore of the socket. The material used for the permanent serving shall be tinned or galvanised soft wire or strand for zinc/zinc alloy coated wire rope, and uncoated (bright), tinned or galvanised soft wire or strand for uncoated (bright) wire rope. 5.2.4 Cutting of rope The wire rope shall be cut by abrasive wheel, percussive or shearing methods, paying particular attention not to disturb the position of wires and/or strands below the permanent serving If oxyacetylene or cutting methods that fuse the wire rope end – i.e. fuse & taper machine – are used, then the rope shall be trimmed back with a disc cutter to remove the heat affected zone. SIST EN 13411-4:2011
EN 13411-4:2011 (E) 10 5.2.5 Cleanliness of socket Dirt, grease, scale or residues shall be removed from the inside of the socket basket
NOTE This does not preclude the use of a releasing agent when socketing with resin. 5.2.6 Inserting rope into socket One of two procedures shall be used to insert the rope into the socket. In the first method, the rope shall be inserted into the socket prior to the preparation of the brush.
In the second method, after the brush has been prepared in accordance with 5.2.8 to 5.2.10, it shall be closed and compacted to enable it to be inserted into the bore of the socket without damaging the rope. 5.2.7 Opening the brush The temporary serving at the point of cut shall be removed and the strands fanned outwards to facilitate the brushing operation. The rope (including any steel core where appropriate) shall be unlaid into its constituent wires to form an open brush (see Figure 2). The opening angle of the brush should not exceed 450 from the vertical (see Figure 2).
NOTE Wires should not be bent to an excessive angle at the permanent serving, since this can adversely influence the life of the socket assembly. Special care should be taken with locked coil rope due to the sensitivity of the locked coil wire section.
Any fibre core shall be removed from the whole length of the brush. When socketing fibre core ropes using molten metal, the exposed end of the fibre core shall be protected from the effects of heat created by the molten metal so that the fibre core material does not ignite, melt or otherwise burn, smoke or smoulder. One method to achieve this may be to replace the fibre core with a false steel rope core over a length of 15 x rope diameter (15d) beyond the socket and >1d inside the socket. SIST EN 13411-4:2011
EN 13411-4:2011 (E) 11
Key 1 permanent serving 2 temporary serving Figure 2 Brush formation 5.2.8 Pre-treatment of the brush The brush shall be degreased to remove all traces of lubricant. Degreasing shall be by either liquid or vapour methods. It is essential that when using solvents the solvent manufacturer’s instructions are followed. Care shall be taken to ensure that degreasing is confined to the brush. The wire brush shall be completely dry before the socketing medium is poured into the socket. NOTE When socketing with lead-based alloys the wires of a bright rope may be pre-treated for improved adhesion. An optional procedure is given in Annex D (informative). 5.2.9 Hooking Where type testing shows that hooking is necessary, the dimensions and shape of the hooked portion shall be limited such that it shall not impede the flow of the molten metal or resin during socketing, nor reduce the embedded length of the brush in the socketing medium. NOTE Ropes with coarse constructions i.e. 1 x 7, normally require hooking to insure compliance with this European Standard. 5.2.10 Positioning and alignment of brush, rope and socket The brush shall be re-shaped into a form approximating the shape of the socket basket. The socket shall be drawn over the brush until the root of the brush protrudes into the tapered portion at the small end by no more than 0,5 d. The wires shall be evenly distributed within the socket basket. SIST EN 13411-4:2011
EN 13411-4:2011 (E) 12 The distance between the end of the brush and the large end of the socket basket shall be no greater than
5 % of the length of the socket basket. If the ends of the wires at the top of the brush do not protrude beyond the large end of the socket basket, the actual position of the wire ends in relation to the large end of the basket shall be measured and documented. The rope axis shall be coincident with the socket axis for a sufficient length, typically three lay lengths, but may be reduced by the use of suitable clamps. NOTE The concentricity of the rope in relation to the socket bore is part of the negotiation. 5.2.11 Sealing The area where the rope enters the bore of the socket shall be sealed with a material that prevents leakage of molten metal or resin.
NOTE Care should be taken to ensure that the sealing material is not pushed into the gap between the socket and rope at the bore. If this occurs, it might prevent penetration of the socketing medium into the socket bore region, which could lead to corrosion and reduced life of the assembly. 5.3 Socketing 5.3.1 General The medium used for socketing shall be either: molten metal conforming to Annex A (normative); or resin conforming to Annex B (normative). Previously used socketing medium shall not be re-used. 5.3.2 Molten metal socketing 5.3.2.1 Pre-heating the socket The socket manufacturer shall provide the maximum temperature to which the socket can be heated without adversely affecting the socket material properties.
The socket shall be heated to ensure that the molten metal is able to fill the socket basket without solidifying prematurely. Unless specified otherwise in these instructions, the socket pre-heat temperature shall be at least 50 % of the pouring temperature of the socketing medium. The pre-heat temperature shall be achieved gradually b
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