In response to the country's initiative to vigorously promote energy conservation and emission reduction, for the purpose of satisfying both flue gas corrosion requirements and chimney reliability, a titanium-steel composite plate steel chimney inner tube was added to the original reinforced concrete chimney. In order to improve the service life of the chimney, Baoji Taicheng Clad Metal Materials Co., Ltd, as a metal clad plate manufacturer, would like to introduce the knowledge of relevant welding technology to you.
Welding of titanium steel clad plates
1) The welding area should be relatively independent and kept clean. Necessary wind and rain protection measures must be taken for welding to ensure that the relative humidity within 1m of the welding area is not greater than 90%, and the temperature of the titanium plate is not greater than 100 °C.
2) Before welding the base layer, the oil, water, and other contaminants within 20mm of the groove surface must be thoroughly cleaned to show the original luster of the metal, and pay attention to protection.
3) Before cladding welding, the welding groove and the area of 50mm on both sides must be thoroughly cleaned.
4) Use stainless steel or copper brush to remove oxide film, burrs and surface defects, etc. The cleaning tools must be dedicated and kept clean.
5) Preliminary chemical cleaning. Use sulfur-free acetone or ethanol for degreasing treatment, and it is strictly forbidden to use chlorinated solvents such as trichloroethylene and carbon tetrachloride, and cotton fibers must not remain on the surface of the groove.
6) After the chemical cleaning is completed, use non-cotton fibers to wipe and dry the groove surface as soon as possible. After chemical cleaning, more than 6h need to be cleaned again.
7) The surface of the welding wire and titanium strip must also be thoroughly cleaned before welding. The cleaned titanium welding wire and titanium strip must be wrapped with non-cotton fibers and put into a special welding material cylinder for immediate use. The amount of each cleaning should be the amount used within 6 hours. More than 6 hours after cleaning needs to be cleaned again.
Before welding, the near seam area of the welding groove and the welding consumables must be cleaned again. Manual tungsten argon arc welding is used for cladding sealing to ensure good fusion and penetration on both sides of the weld. When the titanium layer is welded, the interlayer temperature or the surface temperature of the titanium plate shall not be greater than 100 ℃. When the titanium layer is welded, the tail of the weld must be protected to prevent oxidation. When titanium cladding is welded, the end of the welding wire must always be kept in the shielding gas of the welding gun. If the end of the welding wire is found to be oxidized, it must be removed. The corner joint between the titanium cladding and the titanium cover plate shall ensure that the root is fully welded, and the two sides of the full weld shall have a smooth transition. When welding the titanium surface, arcing on the surface of the workpiece outside the groove is not allowed. Any contact with the titanium-steel composite board (cladding) should be made of stainless steel, copper, wood, or hard plastic tools as much as possible.
Post weld inspection
1) Before the inspection, the welder cleans the slag and spatter; the surface of the weld and the heat-affected zone shall not have defects such as cracks, pores, slag inclusions, and incomplete welding of arc craters. The forming should be good, the welding seam and the base metal should have a smooth transition, the height of the welding angle should meet the design requirements, and the width of the butt weld should cover the groove on each side by 1~2mm.
2) After the welding is completed, the welder should conduct self-inspection on the dimensions and surface quality of the weld. The inspection items mainly include the flatness, excess height, undercut, surface pores, cracks, weld size, and deformation of the weld.
The welding seam metal is allowed to be higher than the sticker after forming, but it should not be super high by 0.5mm, and the appearance inspection rate is required to be 100%; the welding seam layout and dimensions should meet the design requirements; the welding seam forming should be uniform, dense, and smooth transition to the base metal, There shall be no defects such as cracks, pores, tungsten inclusions, unfused, undercuts, arc craters, etc. After removing the defects, the surface of the weld shall not be lower than the surface of the base metal, otherwise, repair welding shall be carried out. The surface of the weld is not allowed to have defects such as cracks, pores, slag inclusions, and unfusion, the undercut depth is less than 0.5mm, the appearance of the weld is good, the weld transition is smooth, the weld wave is uniform, and the weld width is even and straight. The surface of the welding seam is not allowed to have obvious scratches and other defects. The color of the titanium weld and the surface of the heat-affected zone is qualified as silver white, light yellow, golden yellow, and light blue. If the weld surface is gray or has white powder, it must be repaired.
Titanium-steel composite plate steel chimney installation project not only improves economic benefits but also actively responds to the country's initiative to vigorously promote energy conservation and emission reduction. To buy titanium steel composite plates, look for Baoji Taicheng Clad Metal Materials Co., Ltd!
