Company : SAREL ENGINEERS
City : Mumbai

Name of the PRODUCT: RETUBING & TUBE EXPANSION

PRODUCT Code : S-17

Description/Specification of the PRODUCT :
After successful removal of tubes from reclaimed tubesheet, it is necessary to inspect tubesheet holes dimensionally to assess the deviation or variation of dimension with respect to its original tubesheet holes dimensions stated in drawing. It is observed that while retubing strength expanded tubesheets vary most in dimension than light expanded tube sheet holes. Due to higher limit of % of thinned tube expansion or marginally over-rolled tube, tube sheet holes are found oversize, oval ligaments disturbed or even digmarks in tubesheet holes. In such condition customer should not expect the same parameters established as earlier in original construction condition. It is a challenging work to carry out tube expansion according to the merit of individual hole dimensions. Tube expansion, whether fresh or retubed it is most important that the quality of tube expansion depends upon: 1. Quality Tube Expander Sets : 2. Appropriate parameters calculations of required working conditions 3. Alert attention of expansion operator 4. If the expander components are precisely manufactured in very close limit of tolerance with perfect heat treatment cycle observed to a special alloy steel recommended for the tube components then end results of expansion carried according to parameters fixed in mock-up holds good. But one of the factor is not matching as above mentioned even 10% thinning may not sufficient and may lead to distort ligament and in future retubing of same tubesheet may not quality for reclaiming condition. Experience operators should be appointed to carry out such tube expansion and at the same time, should be alert to understand replacement of tooling according to the working experience, properties of tube qualities etc. To establish the parameters of tube expansion wall thinning of expanded tube determines the power of strength of holding joint and it is established by the specified operating conditions that the equipment must withstand and for the reason push-out of expanded tube is tested by pull-out method. Supposing pull-out load is required to be minimum 1000kg and consistent ten numbers of tubes are expanded at 3.5 to 4.5% thinning and their pull-out load is observed to be 1100 plus then thinning parameters should not be exceeded beyond 5%. Over-rolling must be avoiding at any case.