Possible consequences of nonstationary loads on the durability of welded joints for low-alloy steel fittings

Structural low-alloy steel grade 09G2S is used in almost all industries. This steel is known in many countries, for example: in the USA it is known as A 516-55, in Japan — SM41B, SB49. The use of this steel is due to its easy weldability by welding, increased strength and wear resistance, and a wide range of operating temperatures. These steels are suitable for the manufacture of various equipment, for example, heat exchange equipment, columns, reactors, tanks, pipe fittings, etc. It is known that such devices operate under pressure, therefore, the behavior of the welded joint with a simultaneous sharp pressure relief and temperature increase in the equipment is of particular interest. For example, in case of a fire on a sealed apparatus, the personnel will abruptly relieve the pressure in the apparatus. How will the weld behave? What can happen to this connection?