Microstructure and mechanical properties of as-deposited and heat-treated additive manufactured 9Cr steel

ABSTRACT

Wire arc additive manufacturing technology has been applied to fabricate 9Cr ferritic/martensitic steel. The steel is widely used in the power industries because of good performances. The effects of different heat treatment conditions on microstructure, hardness, tensile properties, and Charpy impact toughness were investigated. The results show that the microstructure of the as-deposited condition consists of untempered lath martensitic with high strength and low toughness. It was found that heat treatment can change the microstructure characteristics. Moreover, samples after heat treatment have been observed with high elongation and impact toughness but relatively low hardness and tensile strength. The better combination of strength, ductility and microstructure were obtained for the normalising temperature of 1323 K and tempering temperature of 1033 K.

KEYWORDS:

• Wire and arc additive manufacture
• 9Cr ferritic/martensitic steel
• microstructure
• mechanical properties

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the National Natural Science Foundation of China [grant number 51575401]; Zhejiang Provincial Natural Science Foundation [grant number LY16 E050007].