CUI Juan
,
LIU Yazheng
,
PAN Hui
,
GAO Lifeng
钢铁研究学报(英文版)
The microsturctural transformation of austenite grain, pearlite interlamellar spacing, and lamellar cementite thickness of spring steel 60Si2MnA for railway were studied in the hotrolled and reheated states. Furthermore, the effect of microstructural characterization on its final mechanical properties was discussed. The results showed that as far as 60Si2MnA, the pearlite interlamellar spacing determined the hardness, whereas, the austenite grain determined the toughness. Compared with microstructure and mechanical properties in the hotrolled state, after reheating treatment at 950 ℃, its average grain sizes are apparently fine and the pearlite interlamellar spacing and lamellar cementite thickness coarsen to some extent, but both hardness and impact toughness increase to HRC 48 and 85 J, respectively. In the course of making spring, the optimum reheating austenitizing temperature for the 60Si2MnA steel is 950 ℃.
关键词:
austenitizing temperature;austenite grain;pearlite interlamellar spacing;hardness;toughness
ZHANG Chaolei
,
LIU Yazheng
,
JIANG Chao
,
XIAO Jinfu
钢铁研究学报(英文版)
Influence of vanadium and/or niobium additions on delayed fracture behavior in high strength spring steel was studied by hydrogen permeation method and slow strain rate technique (SSRT), and its mechanism was analyzed. The results show that apparent diffusion coefficient of hydrogen in microalloyed spring steels NbVsteel and Nbsteel is lower than that in nonmicroalloyed steel 60Si2MnA. Percentage of strength reduction in SSRT in air after precharged hydrogen of the microalloyed steels is smaller than that of 60Si2MnA. Addition of the microalloys changes the fracture characteristics. Thence, vanadium and/or niobium additions are a very effective and economy means to improve the hydrogeninduced delayed fracture resistance of high strength spring steel.
关键词:
spring steel
,
microalloy
,
hydrogeninduced delayed fracture
,
slow strain rate technique
,
hydrogen permeation
XU Jinqiao
,
LIU Yazheng
,
ZHOU Shumei
钢铁研究学报(英文版)
With the investigated subject of 82B rod, the interlamellar spacings of pearlite at different isothermal transformation temperatures and different cooling rates during continuous cooling transformation were measured, and the effect of the isothermal transformation temperature and cooling rate on the interlamellar spacing was analyzed quantitatively. Moreover, the relationship models between undercooling and interlamellar spacing were presented by data regression. The experimental results show that the relationship between undercooling and reciprocal interlamellar spacing remains linear when the undercooling is not very large, or else, the interlamellar spacing tends to be constant and the relationship will deviate from linearity.
关键词:
interlamellar spacing;calculation model;highspeed rod;82B
