| Title |
Effect of Tempering Conditions on Mechanical Properties and Microstructues of Ti Modified HY180 Steels |
| Authors |
조규봉(Gyu Bong Cho) ; 남태현(Tae Hyun Nam) ; 안인섭(In Shup Ahn) |
| Abstract |
Changes in microstructures and mechanical properties of HY180 steels with tempering condition have been investigated by means of scanning electron microscopy, transmission electron microscopy, vickers hardness test, tensile test and Charpy impact test. Rehardening phenomena distingushed from the secondary hardening occurred in HY180 steels on tempering below 813˚K The maximum hardness(Hv 540) and tensile strength(1370㎫) were obtained in a 0.05wt%Ti-HY180 steel tempered at 753 K for 20 hours. This is attributed to the very fine(50㎚ M₂C(M=Mo,Cr)) carbides which appeared to be peculiar tc the rehardening phenomena. The maximum impact absorption energy(208J) was obtained in a 0.05wt%Ti-HY180 steel tempered at 753 K for 10 hours. This was due to complete dissolution of brittle cementite. |