Welded
steel pipes and tubing are used in a number of applications where high demands are set on reliability, strength and corrosion resistance. These high performance pipes and tubes are alloyed with higher contents of molybdenum and nitrogen in order to improve the corrosion resistance and the strength, and are welded with over alloyed filler metals and/or with nitrogen added to the shielding gas, in order to become as high pitting corrosion resistance as possible in the weld.
Pipes made of nitrogen alloyed chloride resistant grades in the presented applications are welded with the addition of nitrogen in the shielding gas. Most of the pipes are also welded with filler metal and heat treated when specified. Welded
steel pipes and tubing come in improved design properties and are much higher corrosion resistance than other conventional steel pipes.
Depending on how and where the pipes will be used it is up to the end user to decide which type of heat treatment is necessary. Chloride environments give however a risk for pitting, crevice and stress corrosion for standard steels. The pipes are used in all types of corrosive environments in industries such as, chemical, metallurgical, energy, oil & gas, pulp & paper, ships, desalination, and food.
