WELCOME TO WORKSHOP ON MOBILE FLASH BUTT WELDING 15/16.03.2018 PRECAUTIONS IN EXECUTION OF IN-SITU/ON CESS MOBILE FLASH BUTT WELDING STEPS INVOLVED BEFORE STARTING WORK Before participation in the Tender - General QAP shall be got approved by the firm from RDSO. Para 5.6.2 Annex X Manual for FBW (2012)
On award of Contract - Firm to approach CTE office through concerned division for approval of welding team Para 5.6.2 Annex X & Para 13 After approval of welding team - Final QAP to be submitted by the firm to RDSO for standardization of welding parameters Para 5.6.2 Annex X After standardization of welding parameters - Final approved QAP will be issued by RDSO for undertaking of work in field as per provisions of Manual. For field approval of production - Do 30 welds on track (in 2 shifts) in presence of Engineer in-charge, if they satisfy the weld acceptance criteria i.e. visual, dimension, USFD, Transverse test defined in Para 18.104.22.168, 22.214.171.124, 126.96.36.199, 188.8.131.52 of Manual
Approval shall be granted by CTE. SUBMISSION OF GENERAL QUALITY ASSURANCE PROGRAMME 1 General QAP, in triplicate, as per manual shall be submitted to RDSO by agency/plant owner separately for each mobile flash butt welding plant proposed to be deployed. Availability of Railways order will not be required at this stage. 2 The complete QAP (Excluding details of welding team, details of contract agreement and standardized welding parameters) so submitted by firm will be scrutinized and approved by RDSO after ensuring compliance of relevant provisions of this manual. 3 One approved copy of General Quantity Assurance Programme will be returned to agency, which has approached for approval . APPROVAL OF WELDING TEAM Para 5.6.2 Annxe X & Para 13 On award of Contract firm to approach concerned Zonal Railway for approval of welding team .
Welding team may consist of one supervisor and two welders. The educational qualification of supervisor should be min. Diploma in Mechanical / Electrical Engineering or B.Sc. and that of welder should be minimum class X or equivalent, passed. Competency Certificate to welding operators /supervisors will be issued by CTE of Zonal railway after conducting necessary test as per manual and other instructions on subject. STANDARDIZATION OF WELDING PARAMETERS Weld Parameter depend on section & metallurgy of rail to be welded Para 5.6 After final QAP submitted is found satisfactory
during scrutiny the standardization of welding parameter for concerned Rail section /UTS as requested by agency/ zonal railway will be undertaken by RDSO The standardized welding parameters will be advised to agency/zonal railway . SUBMISSION OF FINAL Q A P After approval of the welding team concerned Zonal Railway, the firm to undertake internal test to provisionally fix the welding parameters for rails of different sections/ metallurgy as required to be welded as per contract. Then agency will submit the final QAP (Duly updating the earlier approved General QAP with details of welding team approved by zonal railway with competency certificates, proposed welding parameters as decided by firm during internal test and details of contract agreement) in quadruplicate to RDSO through
concerned Railway administration. Final QAP to be approved by RDSO. SUITABILITY & PREPARATION OF RAILS FOR WELDING Para 3 of Manual Difference in Height of Rail Ends Maximum 1.2 mm at the welded joint. To be transposed to the foot of rail. Difference in Width of Rail Head 1 mm for New & 2 mm for Old rail Rail End Geometry End bend in vertical plane 0.7 mm on 1.5 m st. edge. Sagging end not permitted End Bend in Horizontal plane 0.7 mm on 1.5 m st. edge. Deviation of End from Squareness 0.6 mm Para 4
End Cleaning End faces & electrode contact locations to be cleaned by brushing & shotblasting / grinding To avoid arcing at contact points & to eliminate rail failure due to copper penetration & brittle martensite structure. PROCEDURE OF WELDING OF RAILS Para 5 of Manual Electrical Contact Electrical Contact i.e. Copper/Melloroy electrode to be cleaned by compressed air pistol Replace electrode depression > 1 mm Ensure adequate spare electrodes. Welding Sequence Aligning Flashing Forging (Upsetting) Recommended Butting pressure 90 UTS rails 6 kg/mm2 Stripping
Record of Welds: Para 6 Record of all the joints shall be maintained in a register as per Performa of record of welds. 1. Date of welding. 2. Shift (day/night) 3. Joint Number 4. Length of rail 5. Section of rails 6. Welding current( Primary, amps) 7. Primary voltage (volts) 8. Clamping pressure Kg / cm2
9. Butting pressure Kg/cm2 10. Number of pre- heats 11. Pre heating time on .. Off.. 12. Burn off time (Sec.) 13. Flashing Time (Sec.) 14. Post welding heat treatment if any. 15. Whether automatic weld record chart available. 16. Remarks ( Any change of voltage during welding etc.) 17. Signature of welder. 18. Signature of foreman TESTING OF WELD Para 10 Test For Every Joint Visual Inspection Dimensional Check Ultrasonic Test (USFD) Test on Sample Joint - not less than 1.5 m length
Hardness Test 1 in 100 upto 1000 joints then 1 in 500 joints Transverse Test 1 in 100 upto 1000 joints then 1 in 500 joints Macro & Micro Examination 1 in 1000 joints FINISHING TOLERANCE Welds with New Rails i Vertical misalignment: ii Lateral misalignment: iii Head finishing (in width):
Side of rail head should be finished to : 0.25 mm on gauge side at the center of 10 cm straight edge. iv Finishing of top table surface: V +0.3 mm at the center of a 1 m -0.0 mm straight edge. +0.3 mm at center of a 1 m st. edge. + 0.2 mm at the center of 10 cm - 0.0 mm straight edge. Web zone (under side of head : + 3.0 mm
web, top of base, both fillet - 0.0 mm of the parent contour each side) vi Upper side, under side surfaces and edge of rail foot shall be ground smooth. The edges of foot should be rounded and bottom of rail foot ground smooth without any minus tolerances to ensure proper seating on sleepers, unhindered movement of welded panels on end unloading rakes, avoid to damage elastic rail pads and eliminate stress raiser. NOTE: Tolerances for BSP rail rolled as per explanatory note for IRST 12/2009 shall be as under. (a) Vertical misalignment- +0.4 mm at the center of 1m straight - 0.0 mm edge. (b) Lateral misalignment - 0.4 mm at the center of 1m st. edge.
FINISHING TOLERANCE Welds with Old Rails i Vertical misalignment: 0.5 mm straight edge. ii Lateral misalignment: iii Head finishing (in width): Side of rail head should be finished to : 0.30 mm on gauge side at the center of 10 cm straight edge. iv
Finishing of top table surface: V at the center of a 1 m 0.5 mm at center of a 1 m st. edge. 0.2 mm at the center of 10 cm st. edge. Web zone (under side of head : + 3.0 mm web, top of base, both fillet - 0.0 mm of the parent contour each side) HARDNESS (BRINNEL HARDNESS ) TEST Hardness Value in HAZ v/s parent rail 20 HB
Not more than TRANSVERSE TEST VALUES OF MINIMUM BREAKING LOAD AND DEFLECTION IN TRANSVERSE LOAD TEST SL No 1 Rail section 60 kg (UIC) grade 1080 HH Span
Min breaking load (tonnes) Min. deflection at center of the actual transeverse breaking load mm Frequency of testing Stationary FBW Plant Mobile FBW Plant 1.25 m
115 30 1 in 500 1 in 100 1.25m 110 12 1 in 500 1 in 100
3 60 kg (UIC) 90 UTS 1m 150 20 1 in 1000 1 in 100 4 52 kg 90 UTS
1m 115 20 1 in 1000 1 in 100 5 60 kg UIC MM (72 UTS) 1m 135
30 1 in 1000 1 in 100 6 52 kg MM 72 UTS 1m 100 30 1 in 1000
1 in 100 2 60 kg (UIC) grade 1080 CR REGISTERS TO BE MAINTAINED Para 5.6.2 Annexure - XI 1. 2. 3. 4. 5. 6. 7. 8. 9.
10. Record Of Weld Register Dimensional Check Register USFD Test Register Hardness Register Transverse Load Register Macro Examination Register Micro Examination Register Daily Progress Register Joint Rejection Register Customer Complaint Register Marking of Joints: Para 9 Every joint shall have distinctive mark indicating the weld number, month and year of welding and the code of the plant. (A) For Stationery Plant :XXXX MM YY AAA XXXX Ist 4 digit weld no. starting from 0001 for first weld of every month MM Month of Welding
YY Year of welding AAA Code of Welding plant (B) For Mobile Plant:XXXX MM YY OO PP EE XXXX Ist 4 digit weld no. starting from 0001 for first weld of every month MM Month of Welding YY Year of welding OO Code of owner of plant PP Code of the plant of that owner EE Code of agency executed the welding work PRECAUTIONS TO AVOID DEFECTS IN FBW Para 10 Annexure V Oxide inclusion Remove loose scale, rust, scabs, dust, paint etc. By grinders, brushing or shot blasting and oil, grease by using carbon tetrachloride or benzene. Lack of fusion- Proper flashing and butting stroke. Poor joints due to defect in rail- Cropping of defective rail end. Notches and chisel marks adjacent to the weld joints- notch or
dent mark are not formed at rail surface during stripping and grinding. Copper penetration/arching on rail foot bottom surface- loose oxide/metal shall be cleaned and copper block shall be replaced when depression measured more than 1 mm. Use of treated water for cooling systemEnd squareness to be ensured. Sufficient enough out put of secondary current be ensured. Butting stroke should be sufficient. Proper Trimming of squeezed metal and grinding to be ensured. Minimum and nearly parallel HAZ by setting the weld parameters. Auto recording of weld parameters including final butting Periodical Maintenance of Mobile FBW - Para 14 As per procedure and frequency laid down by OEM Use genuine spare parts either supplied by OEM or
procured from sources recommended by OEM. Periodical Inspection of MFBW Plants Para 14.1 By OEM or his authorized representative in two years or execution of 20000 joints, which ever is earlier Minimum Equipment and Machines Para 14.2 Sufficient stock of genuine spare parts & consumables As per list in Annexure IX HANDLING OF 90 UTS RAILS Para 11 & Annexure VII AVOID Heavy static loading
Sudden impact Localised point or line contact loading in stacking. Excessive end drop and flange overlaps while lifting/moving. Criss-cross stacking of rails to alternative layers at right angle as far as possible. Single point slinging. DO Keep rails horizontal straight while lifting/moving Stack rails same length on firm level base well drained platform, preferably of concrete, as per RDSO drawing . Stack subsequent layers on uniformly placed spacers in vertical alignment with base supports. Keep rail ends in vertical alignment. Place rail in shorter length in upper layer. CHECK LIST FOR FLASH BUTT WELDING PLANTS ITEMS TO BE CHECKED DAILY
UNLOADING OF LOOSE RAILS FEEDING OF RAILS Rails ends have been checked for Straightness Squareness Width of head and height Fish bolt holes /Any other drilled are chamfered Rail ends are cleaned of rust, scales, paint etc. Top of rails head and bottom of rail foot are clear at electrode position Grease/Oil at rail ends if present has been removed with carbon
tetrachloride benzene. Rails of same section and UTS are stacked together Spacers are provided between successive layers of rails Rail are stacked in head up position Numbers of layers in each stack is not exceeding 15. WELDING Alignment of rail ends is proper and checked with 1 meter straight edge
Electrodes surfaces are clean (Cleaning after every welding operation) Stipulated oil and air pressure is available in the welding machine. Record of each welds kept in prescribed perform. FINISHING OF JOINT Stripping / trimming of entire weld cross section has been done Notches /undercuts are avoided while stripping with pneumatic chisel. Post weld controlled cooling is done for Cr- Mn/head hardened rails. Joint has been checked for A) Straightness on (i) 10 cm st. edge (ii) 1 m st. edge Dimensional tolerances Joint is numbered
B) TESTING OF JOINTS Joint is ultrasonically tested using normal, double crystal 70 and 45 probes. Ultrasonically defective joint ID prominently marked Joint is dimensionally correct ( on 10 cm and 1m straight edge ) Records of each test are maintain in prescribed Performa DESPATCH OF PANELS Panels of same rails section and UTS are stacked together. Spacers are provided between successive layers of panels Panels are stacked in head up position.
Number of layers of panels is not exceeding Rails are placed on roller without impact. Loading of welded panels in EUR is being done in pair of equal length. ITEMS TO BE CHECKED WEEKLY Electrodes have been machined before formation of 1mm deep groove. Standard welding parameters are correctly set for the type and section of rails being welded. Panels with defective joints are separately stacked. Movement of hoists in lateral and vertical direction is well synchronized. Work spot is clean and tidy. While unloading, the rails are held at two points 6-6.5 m apart and overhang of ends does not exceed 3-3.5 m. Rails/panels are stacked on leveled and well drained platform and
they have no contact with soil. Transverse testing & Macro examinations of test welds is done at prescribed frequency and records are maintained. Transverse testing machine is calibrated. Workmen are provided with required protective clothing. THANKS
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