BS/EN 16771-2016 pdf download.Railway applications Infrastructure Aluminothermic welding of grooved raIls.
railway regulator: or owner of a railway infrastructure, or custodian with a delegated responsibility for a railway infrastructure
3.8
process supplier
company which provides an approved aluminothermic welding process in accordance with this standard
4 Information to be supplied by the railway authority
The following information shall be fully documented by the railway authority. For compliance with the standard both the definitive requirements specified throughout the standard and the following documented items shall be satisfied:
a) which of the width levels of heat-softened zone is required (7.4.4);
b) limitations on the pre-heat to comply with the railway authority regulations.
5 Approval procedure
5.1 General
An outline of the steps required for compliance to this standard is given in informative Annex A. 5.2 Process identification
The approval shall involve a single process identified by:
a) the process name;
b) a drawing of the pouring system and the casting system;
c) the characteristic geometry of the weld collar and riser configuration as given in 5.4.2 and Figure 1;
d) the process manual in accordance with 5.4.1.
5.3 General requirements
The following requirements shall be met:
a) the process shall be capable of being carried out on track and at or near trackside or in a workshop;
b) the aluminotherniic welding portion shall be packed to avoid the risk of moisture contamination in prescribed storage conditions. The portion shall be identified by markings on the package;
c) the mould shall be pre-fabricated for the rail profiles to be welded and be identified by markings on the package;
d) the crucible shall be tapped automatically (automatic tapping) and shall have a device to limit spattering;
e) pre-heating shall comply with any limitations of the railway authority as specified in Clause 4, b).
5.4 Documents to be submitted with the request for approval
When applying for approval, the following documents shall be submitted:
5.4.1 The process manual.
The supplier shall produce a manual identifying all the consumable materials and equipment used, as well as the operating method to be followed for all steps of welding. The approval procedure for laboratory tests will not include means of alignment or finishing operations. The manual shall specify the critical parameters of the welding process and their safe bounds, and shall include the following:
a) number of people required to carry out the operations;
h) diagram of equipment;
c) portion for each rail grade and profile;
d) rail end preparation requirements;
e) nominal gap shall have a tolerance of ± 2 mm for as 30 mm gap and ± 3 mm for> 30 mm to 50 mm gaps and ± 5 mm for> 50 mm gaps;
1) preheating details;
g) range of ignition to tap times for the portions;
h) critical process timings;
i) time (or temperature) before trains can pass;
j) safety information.
Initial compliance can be extended as follows:
The relevant railway authority requirements defined in Clause 4 shall be met for each of the items below:
a) to other group of rail profiles listed in Table I or 2 [5.5’ a)1, by doing the tests given in Table 3 category 1 [5.5, b)] on one profile of the appropriate group. Failure of any test shall cause noncompliance for the group of rail profiles being tested;
b) to other rail grade by doing the tests given in Table 3 category 2 b)J. Failure of any test shall cause non-compliance for that rail grade. Tests on one rail profile cover all profiles in group I or
2.
5.7 Preparation and allocation of test welds
a) Welds required for the tests shall be produced in accordance with the process manual (5.4.1) under the supervision of the approving authority. Rails to be used for the production of test welds shall be new rails. hFty percent ot test welds shall be made with minimum gap and su percent at maximum gap.
b) Welding gap shall be measured after weld alignment (peaking) on both sides of the rail head (or on the running surface), web mid point and both foot tips. The maximum gap is the maximum at any of the above points and minimum the minimum of any of the above points,
c) The weld gap for all welds made for Table 3 tests shall be within the specified range. In the case of the welds required for test H In category 1 of Table 3, one weld shall be produced at the minimum gap and one at the maximum.BS/EN 16771-2016 pdf download.