Monday, February 25, 2019
Cement Kiln Shell Welding
percipiented the weld chamfers free from rust preventive coating. * Welded erection handcuffs (20 Nos) on both sides of the joint & pulled the sections together by draw bolt. * Adjusting custody are welded in between the erection irons where shell lick was found. * Checked the alignment of the shell with Piano wire arrangement. * Gap of 3mm kept up(p) in between the shell joint. * Strong backs will be welded on one shell after initial alignment. * Took polar readings on any side of the joint & both ends of the Shells * Plotted polar diagrams and checked the eccentricity. Tolerances * Eccentricity (radial lean out ) must not exceed * +/- 1. 0 mm of the doorway & 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. join of Joint * Clean the joint push through. * Preheat the joint area of shell ( 1m lg ) to 15 0 deg * Welding electrodes are to be preheated * free the root run on the outer(a) 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 alter rate in the weld area. This may be necessary to revoke cracking of the weld metal or heat affected zone.* hydrogen contributes to delayed weld and /or heat affected zone cracking, indeed 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 9721 E 7018 (4. 00mm) * FLS 9721 E 7018 (5mm) * FLS 9732 E 6027 for Cover Run * E 7018 E 6027 * Yield stress 410-480360-410 N/sq. mm * pliable strength 5 10-590 440-490 N/sq. mm * Elongation 28% 27 * Impact (Charpy V) * +20deg c approx. 14090 * Electrodes used (other joints) * FLS 9727 E 9018 (3. 15mm ) * FLS 9727 E 9018 (4. 00mm) * FLS 9727 E 9018 (5mm) * FLS 9727 E 9018 ( 6mm) E 9018 Yield stress 490-590 N/sq. mm Tensile strength 640-740 N/sq. mm Elongation 25% Impact (Charpy V) +20deg c approx. 180
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