A solution to the Embrittlement after Aging of HR3C

HR3C steel was widely used in superheaters and Reheaters of Million Power Unit because of its good anti-oxidation and corrosion performance and high endurance strength. With the increase of service time, HR3C steel showed obvious aging embrittlement, that is, in the early stage of service, the elongation at room temperature decreased to less than 10%, which posed a threat to the safe operation of units. Although the durable strength of S30432 steel was higher than that of HR3C steel at 600 ℃ ~700 ℃, the anti-oxidation and corrosion performance of S30432 steel was lower than that of HR3C steel because of the less Cr content of S30432 steel, which limited the application of S30432 steel. The research on the anti-oxidation and corrosion performance of S30432 steel was analyzed. The results showed that after surface modification such as shot peening and aluminizing, the anti-oxidation performance of S30432 steel was equivalent to that of HR3C steel. The plastic decline of S30432 steel after aging was analyzed. The results showed that the plasticity of S30432 steel would also decline in the early service, but the aging embrittlement was not obvious. Based on the above analysis, a method of replacing HR3C steel with surface modified S30432 steel was proposed to solve the aging embrittlement problem of HR3C steel.