International Scientific Journals
of Scientific Technical Union of Mechanical Engineering "Industry 4.0"

Many industries nowadays with the development of technology require joints between different types of steel due to its various benefits such as production of lightweight machine parts, production of less expensive components with acceptable properties, high strength, acceptable corrosion resistance. One of the dissimilar welding challenges is the joint between martensitic steel P91 and austenitic steel 304H due to the dissimilarities in their chemical, physical and metallurgical properties. In this paper is going to be analysed the best way of joining the two different types of steel, the proper welding technique, the choice of filler material which according to carbon content can match only to one of the steels. At the end is discussed if the welding performance can meet the requirements of high-quality weld.

The main objective of this paper is to get an accurate result of the mechanical characteristics of welded joints of structural steel performed with two different types of filler material, wire, which are characterized by: simple welding technology, low structural changes of the basic materials, as well as lower cost of welds. The whole research is conducted in accordance with European standards for welding. Research has been conducted on two standard plates made of constructive steel S355J2 + N Z15, with a thickness of 15mm, according to standard EN ISO 15614-1. Both plates are welded with solid wire and metal cored wire under the protection of a gas mixture based on argon, and the whole process is supported by standard documentation. Destructive tests have been performed to determine the welded joints’ quality and influence of different filler materials, such as tensile test, impact test, and hardness test in the weld and heat-affected zone. The experimental results confirm that the gas metal arc welding of structural steel in the protection of inert gas with solid and metal cored wire is a procedure that ensures the quality and safety of welded joints and retention properties of the base material after the welding process.