In order to develop low alloy ultra-high strength steel with super high strength and good toughness

a 15 mm CrNiMo-CrNi3Mo-CrNiMo triple-layer clad ultra-high strength steel is developed by 30MnCrNiMo steel billet and 33MnCrNi3Mo steel ingot

the process consists vacuum combined welding

high temperature rolling

quenching and low temperature tempering heat treatment. The bonding degree and mechanical properties are tested by flaw detection

tensile

impact

cold bending and hardness tests. Microstructure and the impact fracture of triple-layer clad ultra-high strength steel are analyzed by means of optical microscope and scanning electron microscope. Results show that the triple-layer clad ultra- high strength steel produced by current process has good bonding properties and can satisfy the GB/T 7734-2015 I demand of flaw detection. The comprehensive mechanical properties of clad steel plate are fine

and there is obvious transition zone in hardness of the joint surface. Both the structure at bonding site and matrix structure are tempered martensite structure.