1. The key to the manufacture of the header is the welding of the end cap (or head). When welding, most manufacturers use manual arc welding, because the weld is single-sided welding, the root quality is difficult to guarantee, and because of the huge of welding work, number of repairing times, the production cycle is long which cause the entire production process slow.
2. Our company adopt the advanced production technology, well-equipped instrument and sophisticated technology, and invented a submerged arc welding method during the header and cover welding. The character is: In the submerged arc welding machine head threading mechanism fixed connection welding wire guide, along the wire guide head to set the wire guide hole, the wire lead head has a certain degree of curvature, welding the inner wall, the wire guide head extension Into the inside of the welding.
3. The welding method mainly solves the problem that the existing welding method of the boiler header and the end cap (or the head) has the advantages of low processing efficiency, waste of argon at the time of processing, need to open the groove, have many processes, high processing cost and unsatisfactory welding fabrication.
1.Headers form an important part of all types of boilers. Steam from the generating tubes is collected in headers which are therefore always under pressure. This pressure may vary from 300 psi to 2000 psi.
2. Since headers are always under pressure, the utmost care is taken by us while fabricating them. Depending on the generating capacity of the boiler the header sizes fabricated by us vary from 100 mm to 600 mm NB. The stubs of various sizes are very carefully welded to the main body of the header to provide the desired openings from the headers
3. Bevelling and weld preparation of stubs duly tack-welded to the main body of the header are first shown to Chief Inspector of Boilers for his approval and once again the stubs fully welded with main body are shown to Chief Inspector of Boilers under hydraulic pressure, varying from 1000 to 3000 psi as required by the specifications.
4. The headers are stamped by Chief Inspector of Boilers before they leave our manufacturing plant. We also weld skubolets and weldolets in place of stubs.
1. The pressures and temperatures that headers have to withstand depend on the component to which they are connected. A header connected to an economizer or to water wall panels is subject to less severe requirements on the material than a header connected to superheaters or reheaters.
2. Depending on the temperature and pressure of headers, Vallourec supplies tubes in carbon steel to high-alloy ferritic steels such as T/P91 or T/P92, with sizes ranging from 88.9 mm to 406.4 mm.