Microstructures upon explosion welding and processes which prevent joining of materials

Abstract

The present paper examines features of interface structure and analyzes possible risk zones for two to a certain degree alternative objects manufactured from composites produced by explosive welding. One of those is a chemical reactor vessel; the other is a petrochemical reactor vessel (a coke drum). The engineering of a chemical reactor vessel is an example of a successful implementation of explosive welding. The analysis of the chemical reactor wall structure containing a coppertantalum welded joint revealed the reasons for its stability that provides reactor's extended service life in a harsh environment. However, a risk zone can emerge due to the quasi-wave nature of the interface. On the contrary, factors that shorten the service life were found for the petrochemical reactor. The contact zone of the plates for the shell of the petrochemical reactor (the coke drum) produced by explosive welding and made of 08Cr13 and 12CrMo steel consists of five layers. The segregation of carbon provokes the eutectoid decomposition that causes formation of colonies of rod-shaped carbides. As a result, two risk zones can be observed: the melted zone and the segregation zone. Using the copper-titanium joints as examples, the effect of intermetallic reactions on the strength of a welded joint was studied. Disordered and unfaceted clusters were observed to turn into intermetallic particles and then into agglomerates. Attention is drawn to the fact that the variety of operating modes and conditions makes the formation of intermetallic compound really hazardous.

Interfacial Microstructure and Shear Behavior of the Copper/Q235 Steel/Copper Block Fabricated by Explosive Welding

“…Then, under the action of the shock wave, the molten copper and steel mixed together and flowed with the wave crest, and finally converge to the vortex region where the pressure in front of the wave is lowest [1,16,19]. Greenberg et al [22,23] found the same phenomenon in aluminiumtantalum and copper-titanium explosive welding interfaces, vortex zones are formed near the cusps and valleys. Due to the low impact energy, we did not find a similar vortex zone at the lower-interface, as shown in Figure 3c.…”

“…As a resu a number of the most severely deformed copper microstructures melted in the first plac and more liquid copper was mixed with the soften or even molten iron, which can evidenced by the fact that copper occupies more volume fraction in the vortex regio Then, under the action of the shock wave, the molten copper and steel mixed together an flowed with the wave crest, and finally converge to the vortex region where the pressu in front of the wave is lowest [1,16,19]. Greenberg et al [22,23] found the same phenom non in aluminium-tantalum and copper-titanium explosive welding interfaces, vort zones are formed near the cusps and valleys. Due to the low impact energy, we did n find a similar vortex zone at the lower-interface, as shown in Figure 3c.…”