| Explosive welding is a technique which bonds two or more metal materials by using explosive energy. One or more layers of stainless steel, titanium or tantalum can be cladded on the base layer and composite boards with multiple high qualities, such as corrosion resistance, wear resistance and heat resistance, can be obtained. Investigation of the mechanism of the explosive welding process and relevant laws have a significant impact on planning explosive welding process and parameters, so that high-quality composite boards can be obtained. In this paper, the explosive welding process of stainless steel-steel composite plate was simulated numerically using SPH and the interface bonded form and microstructure of a 321/Q345 composite board was researched. Results are as follows:(1) For the explosive welding process of 321/Q345, a 2D SPH explosive welding model was set up. The welding process was simulated numerically and the interface wave formation and the movement tracks of jet flow particles have been extracted. The pressure, velocity, effective plastic strain changing versus time of feature points were analyzed. The results indicate that the explosive welding process can be divided into three parts which are initial impacting, wave disturbing and stable bonding. The cause of interface wave formation accords well with Bahrani mechanism. The particles of jet flow come from both base plate and flyer plate and jet flow can be regarded as failure of metal on surface.(2) Explosive welding process of 321/Q345 composite boards were simulated under different circumstances which were explosive height, explosive detonation velocity, preset angle and interval length. The influence of technical parameters on the pressure, velocity and effective plastic strain were analyzed. Results show that specific wave length ranges from 0.27 to 0.34 changing versus explosive height and explosive height that less than 20mm will lead to the lack of interface wave. Effective plastic strain of the bonding surface decreases with increasing detonation velocity. The increase of preset angle results in the increase of effective plastic strain and number of jet flow particles. Meanwhile cracks will appear when the angle is bigger than 10°. Location offset will increase with the interval length between flyer plate and base plate.(3) Interface morphology and microstructures of a 321/Q345 explosive welding composite board were researched. Results show interface sine wave and straight bonding surface are two main bonding form of the sample. Bonding zones have the features of both pressure welding and fusion welding. Wave bonding zones, which have distinct interface and fiber structures, bonded under pressure. Straight bonding zones have adiabatic shear bands and shear deformation generated mass energy for the interface melting. Straight bonding zones bond through melting. |
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