Development of New Cobalt-Free Maraging Steel with Superior Mechanical Properties via Electro-Pulsing Technology

Abstract

The ductility of cobalt-free maraging steel is unsatisfactory because of the high content of Ti. Traditional heat treatment can not effectively improve the ductility of this kind steel. In this contribution, high-energy electro-pulsing is adopted in a T250 steel to solve this problem efficiently. It is found that the EPS treatment (electro-pulsing treatment under water-cooling condition) can accelerate the formation of retained austenite and nano stacking faults. Meanwhile, the microstructure is also refined by EPS treatment. Then, taking the EPS sample as the initial state, nano-reverted austenite combined with finer η-Ni3Ti precipitates are formed during EPA treatment (electro-pulsing treatment under air-cooling condition), compared with TA (traditional aging) treatment. The results of mechanical properties indicate that the strength and elongation are both enhanced by electro-pulsing treatment. Consequently, the electro-pulsing treatment can be a promising technology to devise cobalt-free maraging steel with better properties.

Interface Wetting and Reaction Behavior between Mold Flux and Submerged Entry Nozzle under an External Electric Field

“…Recently, the application of electric field is widely researched in ferrous metallurgy to improve the metallurgical effect. [17][18][19][20] In the continuous casting process, the mold flux can be seen as charged ions and ion clusters present in the mold. [21,22] The author has used an electric field to promote the electromigration and electrochemical reaction of ions and ion clusters in the mold flux to solve the problem of slag-line corrosion.…”