(1) When CEQ is less than 0.40%, the hardness tendency of 35CrMo steel plate is not obvious and the weldability is good;
(2) When CEQ is 0.40-0.60%, the hardness tendency of 35CrMo steel plate is gradually obvious and its weldability is acceptable. During welding, proper preheating before welding, slow cooling after welding and other technological measures should be taken to control its welding connection energy;
(3) When CEQ is more than 0.60%, 35CrMo steel plate has a strong tendency of hardness and poor weldability. It is a kind of steel that is difficult to weld. During welding, it is necessary to adopt high preheating temperature and strict technological measures to select the appropriate welding materials. By calculation, the carbon equivalent value of 35CrMo steel plate is CEQ = 0.72%.
It can be seen that the weldability of 35CrMo steel plate material is poor. When welding, its hard tendency is large, and the hot crack and cold crack tendency in the heat affected zone are large. Especially when welding under the condition of tempering, the cold crack tendency in the heat affected zone will be very prominent.
Therefore, on the basis of welding 35CrMo steel plate and reasonable welding method, high preheating temperature before welding, strict technological measures and appropriate interlayer temperature should be taken to achieve the purpose of product welding.
