Effects of different SMAW heat input on tensile strength
inpact energy and microstructure onn the welded joint of50 mm Q345 R steel were investigated. The experimental results showed that welding heat had effects on the microstructure and property of the welded joint. With the increase of heat input
the ferrite grain increased and the impact energy decreased.When the SMAW heat input of the Φ5 mm electrod was 27.6 k J/cm
the comprehensive mechanical properties of welded joint could be obtained.