Power Point Presentation Courtesy By: Association of Railway P

Power Point Presentation Courtesy By: Association of Railway P
Power Point Presentation Courtesy By: Association of Railway P.Way Engineers ( Download More Presentation from ARPWE Portal) (

Practical Tips for Defect Free AT Welding &
Preventive Measures to Minimize Weld Fractures By Pankaj Kumar Gupta

KONKAN RAILWAY CORPORATION LTD.
TYPES OF WELDING Flash Butt Welding Gas Pressure Welding Alumino Thermic Welding Metal Arc Welding While Flash Butt Welding is the most suitable method of rail welding, Alumino Thermic Welding is the most popular method of in-situ welding of rails. Nowadays we use ‘Short Preheat Welding’ (SPW/SKV) process. Safety First

PRACTICAL TIPS FOR IMPROVING QUALITY OF WELDS There are Technical as well as Managerial Aspects governing the quality of AT Welds made in the Track. Technical Aspects Upkeep of Welding Equipments Careful choice of Material Careful Preparation of Joint Attention during Welding Operation Some important aspects after Welding Safety First

PRACTICAL TIPS FOR IMPROVING QUALITY OF WELDS There are Technical as well as Managerial Aspects governing the quality of AT Welds made in the Track. Managerial Aspects Testing the knowledge of Welder & Supervisor Cross checking of facts given by Welder/Supervisor Thrust on ‘Quality’ not ‘Quantity’. Regular Training Issue of Charge-sheets Safety First

PRACTICAL TIPS FOR IMPROVING QUALITY OF WELDS Technical Aspects Upkeep of Welding Equipments Crucible should be preheated before starting work. Fresh lining of magnesite in crucible be made after every 3-4 welds. ‘Goose Neck’ should be changed periodically after about 50 welds. Bottom opening of crucible be cleaned soon after welding. Compressed air-petrol pressure in the cylinder should be between psi. The nozzle of the vaporizer must be checked for blockage. Vaporizer must be discarded when nozzle becomes defective. Safety First

PRACTICAL TIPS FOR IMPROVING QUALITY OF WELDS Technical Aspects Careful Choice of Material Moulds Mould surface should be smooth. Ensure that inner walls are painted with ‘Zircon’ to give smooth finish. Dryness of mould to be ascertained by tapping it with small hammer or finger. To ensure mould fully match with rail profile. The practice of locally transforming smaller rail section mould to match higher rail section should be avoided. The storage & handling of mould to be done carefully to avoid moisture ingress or damage. Not to use broken pieces of prefab moulds. Safety First

PRACTICAL TIPS FOR IMPROVING QUALITY OF WELDS Technical Aspects Careful Choice of Material Portion Expire portion should not be used. Portion of proper type conforming to type of rail to be welded to be ensured. The portion should be thoroughly mixed by shaking for ensuring uniform hetrogenous mixture. Luting Sand Luting sand conforming to proper specifications must be used as use of locally available mixture may not seal the joints as desired and it may result loss of weld material. Safety First

PRACTICAL TIPS FOR IMPROVING QUALITY OF WELDS Technical Aspects Careful Choice of Material Sodium Silicate & Magnesite These materials are used to repair refractory linings of crucible. In case of damage of lining, heat loss may take place which can cause early cooling & weak welds. Asbestos Powder Asbestos powder should be put on thimble pin to avoid contact of molten material in crucible with thimble pin before desired time. In the absence of asbestos powder, thimble pin may get melted early causing premature flow of molten material in the opening. Safety First

PRACTICAL TIPS FOR IMPROVING QUALITY OF WELDS Technical Aspects Careful Preparation of Joint The joint should be cut square to avoid uneven heating & poor coalescence of weld material. The Joint should be kept mm high to accommodate shrinkage of molten material as it cools. It will prevent cup formation which given rise to hammering action & early failure of weld. The joint should be aligned to zero tolerance as poor alignment may result in early chipping of finished weld from sides & premature failure. Safety First

PRACTICAL TIPS FOR IMPROVING QUALITY OF WELDS Technical Aspects Attention during Welding Operation The pre-heating burner/welding torch is positioned on torch stand & then removed and set aside for later use. The pre-fabricated moulds, supported in mould shoes, are positioned centrally about/around the gap between rail ends and secured in position. Magnesite lined crucible is supported on crucible stand & manual tapping system is prepared by the appropriate procedure. As soon as the slag separates from the thermit steel, the superheated molten thermit steel followed by its slag is discharged into the moulds at the correct time via the tapping system at the base of the crucible. Safety First

PRACTICAL TIPS FOR IMPROVING QUALITY OF WELDS Technical Aspects Some Important Aspects after Welding Pourer & riser are broken only after they have cooled to atmospheric temperature else higher rate of cooling may cause brittleness.. Re-spacing and packing of the sleepers has been done else weld may get enhanced hammering action. All sand has been removed from the welded joint with the help of wire brush. Filing of the joint has been done within 24 hours. Improper profile cause more hammering action & premature weld failure. Trains must not pass within half an hour of welding else it may cause unevenness due to increased hammering action. Safety First

PRACTICAL TIPS FOR IMPROVING QUALITY OF WELDS Managerial Aspects Testing the knowledge of Welder & Supervisor Welder and Supervisor must be periodically counseled by Inspecting Officials about their knowledge and technique. Cross Checking of facts given by the Welder/Supervisor by PWI The reasons given by the Welders/Supervisors for employing shortcut methods must be cross-checked to know the reality. Thrust on ‘Quality’ not ‘Quantity’ Message that ‘Quality’ is paramount should be spread amongst all Welders/Supervisors. Safety First

PRACTICAL TIPS FOR IMPROVING QUALITY OF WELDS Managerial Aspects Regular Training Periodical training in the form of Refresher Courses must be given to Welders/Supervisors & even to Inspectors so that they may adopt improved practices and discard short cut methods. Issue of Charge-Sheets It has been rightly said that ‘Without Fear Mistakes are Repeated Knowingly’. To prevent this type of attitude amongst the staff, regularly erring employees should be issued with charge-sheets. It should be emphasised that issue of charge-sheet is in the interest of public safety and carelessness has not place on the Railways. Safety First

PRACTICAL TIPS FOR IMPROVING QUALITY OF WELDS Preventive Measures to Minimize Weld Fractures As the saying goes, ‘Prevention is Better than Cure’. The following steps will go a long way in preventing weld failures and consequent safety hazards: Visual Examination Ultrasonic Testing & Follow-up Action Winter Precautions Other Measures Safety First

PRACTICAL TIPS FOR IMPROVING QUALITY OF WELDS Preventive Measures to Minimize Weld Fractures Visual Examination In fracture prone areas, visual examination of rail especially gauge face should be carried out periodically to watch for any crack of kidney formation appearing on the surface of rail/weld. Safety First

PRACTICAL TIPS FOR IMPROVING QUALITY OF WELDS Preventive Measures to Minimize Weld Fractures Visual Examination The rails are known to corrode underneath the liners. Special watch is to be kept for such rails, as fractures are known to initiate from underneath the location of liners. To detect corroded rails/dent mark liners, every length of rail should be seen during foot to foot survey from one end to other by Keyman & other suitable P. Way officials at least three times in a year (one such occasion should be before onset of winter season). If any fissures/corrosion marks/dent marks appear on the rail flange, such rails should be removed. Safety First

PRACTICAL TIPS FOR IMPROVING QUALITY OF WELDS Preventive Measures to Minimize Weld Fractures Visual Examination SEJs must be thoroughly examined by Keymen every week and record maintained. Expansion gaps at rail joints and SEJs should be checked and adjusted and lubrications should be done. In case of LWRs, de-stressing should be done to adjust the gaps. The details of SEJs along with name of firm supplying the SEJs should be kept in record for further investigation. Visual examination of all thermit welds by magnifying glass should be done especially to detect fatigue cracks in foot of weld and action taken wherever necessary. Safety First

PRACTICAL TIPS FOR IMPROVING QUALITY OF WELDS Preventive Measures to Minimize Weld Fractures Ultrasonic Testing & Follow-up Action Frequency of USFD testing shall be strictly followed as per USFD manual and existing instructions keeping in view the fracture proneness of the Sections and there should not be any Section over due. USFD testing of rails upto 16 GMT per annum should be so regulated that one round of testing is done before the onset of winter, i.e. before 31st October. Records of at least five years of testing should be kept. Safety First

PRACTICAL TIPS FOR IMPROVING QUALITY OF WELDS Preventive Measures to Minimize Weld Fractures Ultrasonic Testing & Follow-up Action PWIs/AENs/DENs/Sr.DENs should monitor and check the work of PWI/USFD whenever he is working in their Section. For checking the quality of USFD examination, each fracture should be analyzed and effectiveness of USFD examination judged. Safety First

PRACTICAL TIPS FOR IMPROVING QUALITY OF WELDS Preventive Measures to Minimize Weld Fractures Ultrasonic Testing & Follow-up Action One round of USFD testing for detection of transverse cracks generate from gauge face corner should be carried out as per extant instructions. Marking of rail defects and actions should be taken as per instructions. All IMR & defective Rail/welds should be removed from the track and till these are removed, these should be provided with joggled fishplates with clamps/bolts under speed restriction as prescribed. Safety First

PRACTICAL TIPS FOR IMPROVING QUALITY OF WELDS Preventive Measures to Minimize Weld Fractures Ultrasonic Testing & Follow-up Action All OBS rails/welds should be provided with joggled fishplates and clamps/bolts as prescribed. Provide joggled fish plates with two for end bolts/clamp on all conventional AT welds. Joggled fish plates with two for end bolts/clamps should also be provided on all SKV welds more than 10 years old. Safety First

PRACTICAL TIPS FOR IMPROVING QUALITY OF WELDS Preventive Measures to Minimize Weld Fractures Winter Precautions Analysis of rail fractures and weld failures should be done on the Division to identify the block sections which are fracture prone to identify the reasons for fractures and to take preventive measures. Safety First

PRACTICAL TIPS FOR IMPROVING QUALITY OF WELDS Preventive Measures to Minimize Weld Fractures Winter Precautions Winter de-stressing should be done to reduce the temperature forces, wherever due. However, a record of such de-stressing should be kept so that de-stressing of these lengths is done again before onset of summer. As majority of fractures occur during early hours of morning when rail temperature is minimum, hence during winter months Keymen’s duty roster should be changed to have early morning patrol so that failures, if any, can be detected in time. Safety First

PRACTICAL TIPS FOR IMPROVING QUALITY OF WELDS Preventive Measures to Minimize Weld Fractures Other Measures The fracture report should be made like an investigation/enquiry report. Sectional AEN/DEN/Sr.DEN must visit the site of fracture and adjoining track (1/2 km) on both sides to find out cause of fracture and to see condition of track w.r.t. less ballast cushion, loose packing, missing fittings, condition/missing rubber pads, sleeper spacing, condition of sleeper and rails Safety First

PRACTICAL TIPS FOR IMPROVING QUALITY OF WELDS Preventive Measures to Minimize Weld Fractures Other Measures Analysis of fracture should be done and remedial action taken accordingly. Shallow screening of pumping joints should be carried out. The joint sleeper spacing should be rectified wherever required. Ensure zero missing fittings by recouping deficiency, if any, immediately. Safety First

PRACTICAL TIPS FOR IMPROVING QUALITY OF WELDS Preventive Measures to Minimize Weld Fractures Other Measures Through weld renewal should be planned where incidence of weld fracture is high. It should be planned with flash butt welds with mobile FBW units. All new thermit wells should be ground & finished properly within 24 hours of welding. The first train should be passed only after rough grinding has been ensured. All thermit welding shall be done by trained staff having competency certificate and proper equipments. Ensure that AT welding quality is up to the mark. Safety First

PRACTICAL TIPS FOR IMPROVING QUALITY OF WELDS Conclusion Zero defect AT welding can be achieved by strict quality control measures as discussed here. Managerial aspects also play a vital role in giving defect free welds. The weld fractures can be minimized by adopting preventive measures thus improving safety & ensuring interruption free ride on Indian Railways. Recommendation The filing/grinding of welds must be allowed only with machine operated tools such as weld grinders and weld trimmers to reduce possibility of weld defects due to human error. Safety First

PRACTICAL TIPS FOR IMPROVING QUALITY OF WELDS Profile Grinding (1) Safety First

PRACTICAL TIPS FOR IMPROVING QUALITY OF WELDS Profile Grinding (2) Safety First

PRACTICAL TIPS FOR IMPROVING QUALITY OF WELDS Hydraulic Weld Trimmer Safety First

PRACTICAL TIPS FOR IMPROVING QUALITY OF WELDS Rail Cutting Through Disc Cutter Safety First

PRACTICAL TIPS FOR IMPROVING QUALITY OF WELDS Preparation of Joint Safety First

PRACTICAL TIPS FOR IMPROVING QUALITY OF WELDS Fixing of Prefab Mould Safety First

PRACTICAL TIPS FOR IMPROVING QUALITY OF WELDS Sealing of Joints Safety First

PRACTICAL TIPS FOR IMPROVING QUALITY OF WELDS Preheating of Rails Safety First

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