-Eddy Current Test which scans complete welding area to notice any leakage
Characteristics of Welded Tubes
The heat exchanger tubes from Dost Muhammad Stianless Steel Tubular products are welded from rolled strip this allows the manufacturing of a concentric tube with very narrow tolerances on diameter as well as Products' heat exchanger tubes. This facilitates roller expansion at the fabricator. The low bead is obtained by either bead working after welding, or careful selection of welding parameters. Welding and bead working is followed by heat treatment. which restores mechanical properties and corrosion resistance. Extensive testing ensure the integrity of the finished tube. European pressure vessel rules treat welded and seamless tubes equally, i.e. a weld joint effciency Factor of 1.0 is used for both kinds of tubes. Dost Muhammad Stainless Tubular Products welded tubes have a Weld Joint Efficiency Factor 1.0. This means that the weld has the same strength as the base metal and that the tube can thus be regarded as equal to seamless tube.
Our Heat exchanger tubes are always heat treated. Separate as well as in-line annealing can be offered. The main reason for heat treating welded Cr-Ni-Mo austenitic stainless steel tubes is to reduce chromium and molybdenum segregation. Segregation occurs during the solidification of the weld metal and has a negative effect on resistance to pitting corrosion. For grades with a high Mo content, in-line induction annealing is not always sufficient to fully counter act the negative effect of segregation. Separate furnace annealing with a long soaking time is then necessary.Proper in-line annealing is sufficient, but only in combination with air or water quenching. Optimisation of the welding and heat treatment procedures ensures that the required corrosion resistance and strength are obtained.
Equipment for heat recovery and waste incineration.
Recuperators in the steel industry
Heat exchanger and evaporators in the production of soda, ethylene oxide. Fertilisers, etc
Heat recovery and gas cleaning
Milk pasteurisation, productionof sugar, fruit juices, etc.