| Title |
Local brittle Zone of HSLA Steels (1) ( Microstructure ad Fracture Properties ) |
| Authors |
김병천(Byung Chun Kim); 이성학(Sung Hak Lee); 이두영(Doo Young Lee); 김낙준(Nack J . Kim) |
| Abstract |
This paper presents a correlation study between microstructural parameters and fracture properties in heat affected zones of high-strength low alloy (HSLA) steels, i,e., a normalized steel and four TMCP steels. This allowed a comparison between microstructures such as grain size and the amount of martensite island. The influence of the local brittle zone (LBZ) on toughness was investigated by means of simulated HAZ tests as well as welded joint tests. The LBZ in the HAZ is the intercritically reheated coarse grained HAZ, whose impact energy values decrease monotonically with increasing the amount of martensite islands. Thus, the martensite island is the main metallurgical factor which contributes to local embrittlement in microstructures containing larger volume fractions of martensite island, thereby leading to the reduction of toughness. |