Hardness analysis of welded joints of austenitic and duplex stainless steels

Abstract

Abstract. Stainless steels are widely used in the modern world. The continuous increase in the use of stainless steels is caused by getting greater requirements relating the corrosion resistance of all types of devices. The main property of these steels is the ability to overlap a passive layer of an oxide on their surface. This layer causes that they become resistant to oxidation. One of types of corrosion-resistant steels is ferritic-austenitic steel of the duplex type, which has good strength properties. It is easily formable and weldable as well as resistant to erosion and abrasive wear. It has a low susceptibility to stress-corrosion cracking, to stress corrosion, to intercrystalline one, to pitting one and to crevice one. For these reasons they are used, among others, in the construction of devices and facilities designed for chemicals transportation and for petroleum and natural gas extraction. The paper presents the results which shows that the particular specimens of the ][ joint representing both heat affected zones (from the side of the 2205 steel and the 316L one) and the weld are characterized by higher hardness values than in the case of the same specimens for the 2Y joint. Probably this is caused by machining of edges of the sections of metal sheets before the welding process, which came to better mixing of native materials and the filler metal. After submerged arc welding the 2205 steel still retains the diphase, austenitic-ferritic structure and the 316L steel retains the austenitic structure with sparse bands of ferrite σ. IntroductionDuplex steels are the result of combining the microstructure of ferritic and austenitic stainless steels. In the case of ferritic steel it is primarily a Nickel one and in the case of austenitic steel it is a Chromium-Nickel one. Their advantages results from properties of both mentioned groups of steels. The next advantage is that higher properties could be obtained with lower level of alloying elements, mainly expensive Nickel. What results in lower price of duplex steels. It cause that nowadays the maritime construction are more and more often design using the different duplex steels. It is also related with good weldability of this group of steels. There are analysed other areas of application [1,2]. Among others duplex stainless steel offers also excellent resistant to corrosion and is characterised by the very high mechanical strength parameters. The high corrosion resistance of this steels ensures significantly more uptime than carbon steels and conventional stainless steels. It is particularly visible for the super duplex and hyper duplex steels. On the other hand the light duplex steels characterises by the same level of mechanical parameters like conventional steels.The mechanical strength allows designing lighter constructions, which are more compact and which need less welding operations. The high mechanical properties are the result of combination both

Mechanical properties and corrosion behaviour of duplex stainless steel weldment using novel electrodes

“…There seems to be consistency in the hardness values of all the considered samples of experimentation at the BM zone. The trend of the results of the hardness analysis of the welded samples is consistent with the findings of other investigators 61 , 63 , 64 .

Figure 4 Hardness values of welded joints of DSS samples ( a ) half segment of the welded sample and ( b ) full segment of the welded joint.

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“…There seems to be consistency in the hardness values of all the considered samples of experimentation at the BM zone. The trend of the results of the hardness analysis of the welded samples is consistent with the findings of other investigators 61,63,64 . 65 .…”

Laser Welding of New Grade of Advanced High Strength Steel STRENX 1100 MC

“…Thanks to the higher strength of steel products it is possible to reduce structures or vehicles weight while increasing its capacity [10][11][12][13].…”