A heat treatment method for improving the depth of a surface hardened layer of 40CrNi2Mo

By combining tempering with stress-relief annealing and low-frequency CNC quenching with PAG cooling, the problems of insufficient quenching layer depth and cracks in 40CrNi2Mo alloy structural steel were solved, thereby improving the quenching layer depth and enhancing the strength of the parts.

CN116770027BActive Publication Date: 2026-07-07WUHAN HEAVY MACHINE TOOL GRP
View PDF 2 Cites 0 Cited by

Patent Information

Authority / Receiving Office
CN · China
Patent Type
Patents(China)
Current Assignee / Owner
WUHAN HEAVY MACHINE TOOL GRP
Filing Date
2023-08-02
Publication Date
2026-07-07

Smart Images

  • Figure CN116770027B_ABST
    Figure CN116770027B_ABST
Patent Text Reader

Abstract

The application discloses a heat treatment method for improving the depth of a hardened layer on the surface of 40CrNi2Mo, and comprises the following steps: selecting a blank casting of 40CrNi2Mo, quenching and tempering the blank casting, heating the blank casting at 850 DEG C, keeping the temperature for 6 hours, and water cooling after discharging; heating the blank casting at 580 DEG C, keeping the temperature for 10 hours, and air cooling after discharging; rough milling the blank casting, and then stress relieving annealing, wherein the annealing temperature is 500-530 DEG C, the keeping time is 10 hours, and the blank casting is air cooled after being cooled to 200 DEG C in the furnace. The method can deepen the quenching layer depth and reduce the occurrence of quenching cracking of the part.
Need to check novelty before this filing date? Find Prior Art