Research On The Aging And Laser Welding Of High-strength Maraging Stainless Steel

Maraging stainless steel is widely used in aerospace, ship-building, automotive, militaryand even nuclear industry because of its high strength, high hardness, good ductility,toughness and corrosion resistance. Comparing with the traditional welding methods, laserwelding has the advantage of big penetration, high strength and making high melting pointmaterials weldable.This paper researched not only the effect of aging treatment on the strength, hardnessand corrosion resistance of maraging stainless steel, but also the laser welding and PWHT(post welding heat treatment) of maraging stainless steel.The first part analyzed the influence of aging temperature and time on the hardness ofmaraging stainless steel. The results show that the hardness rises after aging treatment,specifically in the early stages of aging, the hardness increases significantly. We find thatthere are two aging mechanisms in process of aging through the study of aging kinetics ofmaraging stainless steel.In order to research the weldability of maraging stainless steel, the microstructures ofmaraging stainless steel with six different welding parameters were analyzed. Then thehardness, tensile properties and microstructure of welded maraging stainless steel werestudied after aging treatment with different temperatures. The results show that2000W or2500W may be the best welding parameter through observing the morphologies of weldedmaraging stainless steel. And aging treatment is useful for increasing hardness and tensileproperties of welded maraging stainless steel.We all know that maraging stainless steel has a good mechanical property, but itsexcellent corrosion resistance also plays an important role in its widely using. So theinfluence of aging treatment on corrosion resistance of maraging stainless steel in3.5%NaCl solution were researched in the last part of this paper. We find that aging treatment maydecrease the corrosion resistance of maraging stainless steel, but the influence reduces withthe aging temperature going down.