While it is possible to join aluminium easily to most metals using mechanical fastening or adhesive bonding, welding aluminium to steel
requires other techniques such as arc and friction welding. While the lightweighting qualities of aluminium are well known, it is not always possible to completely replace steel with aluminium, which leads to a need to join the two materials. This can prove difficult due to the different melting temperatures and the fact that they are virtually insoluble together. This FAQ investigates the challenges and solutions for welding aluminium to steel:
https://www.twi-global.com/technical-knowledge/faqs/aluminium-welding/aluminium-to-steel
