Cement Kiln Shell Welding
* Cleaned the weld chamfers free from rust preventive coating. * Welded erection irons (20 Nos) on both sides of the joint & pulled the sections together by draw bolt. * Adjusting irons are welded in between the erection irons where shell overlap was found. * Checked the alignment of the shell with Piano wire arrangement. * Gap of 3mm maintained in between the shell joint. * Strong backs will be welded on one shell after initial alignment. * Took polar readings on either side of the joint & both ends of the Shells * Plotted polar diagrams and checked the eccentricity. * Tolerances : * Eccentricity (radial run out ) must not exceed * +/- 1.0 mm of the inlet & outlet rings * +/- 1.5mm of the erection welds. * +/- 1.4mm of kiln section in the live ring.
Axial untruth of live ring must not exceed +/- 1mm * After completion of alignment, weld the strong backs to the other side.
Welding of Joint : * Clean the joint surface. * Preheat the joint area of shell ( 1m lg ) to 150 deg * Welding electrodes are to be preheated * Complete the root run on the outer surface of the joint side with 2.5mm electrode. * Next with 4mm electrode & then 5mm & 6 mm electrodes. * Gouge & remove the root run weld from the inner surface of the joint, check with Dye penetrant for any cracks and start the root run inside. * Complete the inside welding. * Check the joint by Ultrasonic testing. * Importance of Pre-heating: * Preheating slows the cooling rate in the weld area. This may be necessary to avoid cracking of the weld metal or heat affected zone. * Hydrogen contributes to delayed weld and /or heat affected zone cracking, hence it is important to keep the weld joint free of oil, rust, paint, and moisture as they are sources of hydrogen. * Electrodes used ( 1-2 joint) : * FLS 9721 : E 7018 (3.15mm ) Bottom runs * FLS
Axial untruth of live ring must not exceed +/- 1mm * After completion of alignment, weld the strong backs to the other side.
Welding of Joint : * Clean the joint surface. * Preheat the joint area of shell ( 1m lg ) to 150 deg * Welding electrodes are to be preheated * Complete the root run on the outer surface of the joint side with 2.5mm electrode. * Next with 4mm electrode & then 5mm & 6 mm electrodes. * Gouge & remove the root run weld from the inner surface of the joint, check with Dye penetrant for any cracks and start the root run inside. * Complete the inside welding. * Check the joint by Ultrasonic testing. * Importance of Pre-heating: * Preheating slows the cooling rate in the weld area. This may be necessary to avoid cracking of the weld metal or heat affected zone. * Hydrogen contributes to delayed weld and /or heat affected zone cracking, hence it is important to keep the weld joint free of oil, rust, paint, and moisture as they are sources of hydrogen. * Electrodes used ( 1-2 joint) : * FLS 9721 : E 7018 (3.15mm ) Bottom runs * FLS