Flash Butt Welding

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GOVERNMENT OF INDIA MINISTRY OF RAILWAYS

MANUAL FOR FLASH BUTT WELDING OF RAILS

Reprinted 2004 (Incorporating A&C Slip No. 1-6)

Research Designs & Standards Organisation Lucknow-226011

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DocumentsCONTENTS Para No. 1 2 3 4 5 6 7 8 9 10 11 12 SUBJECT Scope Selection of Rail to be welded Suitability of rails for welding Preparation of rails to be welded Procedure of welding of rails Record of welds Post-weld straightening Finishing Marking of joints Testing of weld Handling of high strength rails (90 UTS, HH & 110 UTS) Checklist for flash butt welding plants PAGE NO. 2 2 3 5 5 8 8 9 9 9 12 12

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DocumentsANNEXURES Annexur Description eNo. I Post weld controlled cooling treatment for 110UTS Alloy steel rails II Post weld Air quenching treatment for Flash butt welding of 60 Kg Head hardened rails III Record of welds IV Finishing tolerances for welds V Precautions to avoid defects in Flash butt welded rail joints VI A Dimensional check of welded joints (After finishing) VI B Ultrasonic testing of welded joints VI C Hardness test of welded joints VI D Transverse testing of welded joints VI E Macro examination of welded joints VII Handling instructions for 90UTS and Head Hardened rails VIII Check list for Flash butt welding plants IX List of minimum Equipments & machines required for Flash butt welding plants PAGE NO. 13 14 15 16 18 20 21 22 23 24 25 29 32

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DocumentsFIGURES Figure No. Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure 3.2 3.4 (a) 3.4(b) 3.4(c) 3.4(d) 4.2(a) 4.2(b) 4.2(c) 5.4(a) 5.4(b) Description Sorting of rails to be welded Tolerance on the end bends in the vertical plane Tolerance on the end bends in the horizontal plane Deviation of the rail end from the square Head width checking gauge for 60Kg (UIC) rails Head width checking gauge for 52Kg rails Head width checking gauge for 90R rails Details of A.C. pipe arrangement for controlled cooling Air quenching gadget for enhanced cooling of HH rail joints Tolerance for vertical misalignment of welded joint with new rails Tolerance for lateral misalignment of welded joint with new rails Tolerance for finishing on sides of head of welded joint with new rails Tolerance for finishing top table surface of welded joint with new rails Tolerance for vertical misalignment of high welded joint with old rails Tolerance for vertical misalignment of low welded joint with old rails Tolerance for lateral misalignment of welded joint with old rails Tolerance for finishing on sides of head of welded joint with old rails Tolerance for finishing top table surface of welded joint with old rails (High joint) Tolerance for finishing top table surface of welded joint with old rails (Low joint) Arrangement for stacking of free rails and welded panels 35 36 37 38 39 40 41 41 42 42 43 43 43 44 44 44 45 PAGE NO. 33 34

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Figure 8(a) Figure 8(b) Figure 8(c) Figure 8(d) Figure 8(e) Figure 8(f)

Figure 8(g) Figure 8(h) Figure Figure Drg. 8(i) 8(j)RDSO /T6219

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DocumentsCORRECTION SLIPS

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S.No.

Correction Slip No.

Date of Issue

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DocumentsMANUAL FOR FLASH BUTT WELDING OF RAILSFOREWORD On Indian Railw ays, Alumi no Ther mic (A. T.) Weldi ng, Flash Butt ( Electric Resistance) Weldin g and Gas Pressure Weldin g processes are p resent ly in use for welding o f rail joints . Flash But t Weldi ng is b eing d one on Zon al Rai lway s departmen tally, using Stationa ry Flash Butt Welding Plants of different makes. Mobile Flash Butt Welding Plants, capable of in situ Flash B utt Weld ing of rails joints, are also in oper ation on some of t he Zonal Railways. The Code of Pract ice f or F lash Butt Welding of Rails (tentative) was issu ed in Janua ry, 1972. Revision of this Cod e is being mad e to cover procedures for Flash Butt Welding of heavier and higher strength rails now u s ed on In dian Railways and to incorporate the l atest pr actices. This Code of Practice is being renamed as Manual for Flash Butt Welding of Rails. The Flash But t Welding Plants have to be mainta ined in good health so that we ma y have lease number s of thermit welds and maximum number of flash butt welds on Indian Railways.

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DocumentsMANUAL FOR FLASH BUTT WELDING OF RAILS1. SCOPE

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1.1 The manual g ives details of the types and suita bility of rails to be welded by stationary Flash Butt Welding Plant prewelding inspectio n, p reparation of rail ends before welding, the general procedure of execution of w elding and finishing o f welded joints . It a lso defines geometrical tolera n ces for the f inishe d joints a nd acceptance tests to ensure quality control. 1.2 Weld parameters for different rail sections/chemistry hav e been prescribe d by manufacturers and are uniqu e to the particular welding plants. Should any change in these parameters be considered necessary, the same may be car ried out in consultation with RDSO. 2. SELECTION OF RAILS TO BE WEL DED

2.1 SECTION OF RAILS: Capacity of the individua l plant will determine t he heaviest section a nd type of rail tha t can be welded. New as well as released but servicea ble rails of sam e type (section and metallurgy) shall only be welded together. Welding of r ails of d ifferent s ections metallurgy shall not b e attempted . It is prefera ble that rails rolled by the sam e manufactu rers are weld ed together . Minimum length of old bu t serviceable rails for welding shall be 6 metres. 2.2 WELDING OF OLD RAILS: While welding old rails, it shall be ensured that only serviceable rails are welded. Old rails to be welded shall preferably be match marked before releasing from track to achieve maximum uniformi ty of profiles in weld zone. 2.3 FISHBOLT HOLES: Welded panels (10/20 rails) for laying long welded rails sh all, as fa r as possible, be without fishbolt holes. If dri lling of fishbolt hole is necessitated for the purpos e of handling d uring en d unloa ding, only the second fishbolt hole (one away from th e rail end) need be drilled. In case, welding of new rails with fi shbolt holes ca nnot be avoided, it shall be ensured that the o uter e dge of the hole nearest to the ra il en d is at least 40mm away from the end to be welded to avoid the heat affected zo ne of the weld extending up to the edge of the hole . All fishbolt holes shall be chamfe red before weldin g.

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Documents2.3.1 En ds of old r ails with fishbo lt holes/bond w ire holes shall be cropped by a minimum length of 450mm before welding. 2.4 ULTRASONIC TESTING OF RAILS TO BE WELDED: New and old but serviceable rails sha ll be free from internal defects. In the case of new rails, the ultrasonic testing is required to be done at the rail manufacturers premi s es. Old but serviceable rails shall invariably be tested ultrasonically before they are taken to Flash Butt Welding Plants. 3. 3.1 SUITABILITY OF RAILS FOR WEL DING OLD RAILS

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3.1.1 Defective rails: Rails having crac ks or other defects such as heavy corro sion pits or which are worn by more than 2mm depth at rail seat shall not be welded. 3.1.2 Permissib le vert ical wea r of rail s to be welded: The vertical wear in old rails to be welded (measured as per para 302 (b) (iii) of Indian Railways Permanent Way Manual) shall be withi n the limits specified below:Rail Section 60kg 52 kg 90 R 75 R 60 R Standard height of Minimum height of the new rail worn rail 172.00 mm 164 mm 156.00 mm 150 mm 142.88 mm 139 mm 128.59 mm 126 mm 114.30 mm 112 mm

3.1.3 Permissib le late ral wear of rails to be welded : Old rails to b e welded shal l preferably show similar pattern of side wear and the minim um width of r ail head shall be as specified below:Rail Section 60kg 52 kg 90 R 75 R 60 R Standard width of the head of new rail 72.00 mm 67.00 mm 66.68 mm 61.91 mm 57.15 mm Minimum width head of old rail 66 mm 61 mm 61 mm 56 mm 51 mm

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Documents3.1.4 3.2 Rails with cyclic wear shall not b e welded DIFFERENCE IN HEIGHT OF R AIL ENDS TO BE WELDED: The individual rail ends for n ew rails may have a maximum difference in height of 1.2mm at the welded joints. Rails manufactu red by SAIL with dispensations (having letter D in the rolling mark), may have a maximum difference in height of 1.5mm. This is illustrated in Fig.3.2. The difference in height shall be transposed to the foot of th e rail. DIFERENCE IN WIDTH OF RAIL HEADS TO BE WELDED

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3.3

3.3.1 The di fferen ce in the width of rail heads of two rails to be welded shall no t exceed 1.0mm for new and 2.0mm for old rails. New rails manufactured by SAIL with dispensations (having let ter D i n the rolling ma rk) may have a maximum difference of 1 .5mm in the width of rail heads. For ne w rails, it is p referable to restrict the difference in width of rail heads to 0.5mm by adopting procedure laid-down in para 4.2. 3.3.2 Any difference in the widths of r ail heads at the welde d ends, in case of bot h new and old r ails, shall be trans