摘要
研究了钒微合金化对高强双相钢微观组织及性能的影响。与Fe-0.186C-1.5Mn-0.3Si-0.008N参照钢相比,加入0.14%V带来如下效果:(1)在冷轧及退火状态铁素体晶粒高度细化;(2)严重推迟在连续退火过程中铁素体向奥氏体转变的初始动力学;(3)慢冷条件下铁素体开始转变温度稍微提高,但珠光体和贝氏体转变被抑制,导致淬透性提高;(4)在临界退火温度≤740℃时观察到未溶渗碳体;(5)750℃/180 s退火后铁素体相中发现大量V(C,N)析出(平均直径7.4 nm),而马氏体(奥氏体)中析出物稀少,尺寸更大(平均直径13.4 nm);(6)不含钒参照钢抗拉强度随马氏体体积分数增量为~16 MPa/%,而含钒钢由于晶粒细化和铁素体选择强化,强度随马氏体含量变化增量相当低(~4 MPa/%),在马氏体体积分数>45%变软。
The effect of vanadium microalloying on the microstructure and properties of a high strength dual phase steel was studied. Compared to the Fe-0. 186C-1.5Mn-0.3Si-0. 008N reference alloy it was found that the addition of 0.14 % wt. V resulted in：（1）A very significant ferrite grain size refinement in the cold rolled and annealed state. （2）During continuous annealing the initial ferrite to austenite transfor- mation kinetics was strongly retarded. （3）On slow cooling the ferrite start transformation temperature was slightly increased but the pearlite and bainite transformations were suppressed, resulting in a net overall increase in hardenability. （4）Undissolved cementite was observed at intercritical annealing temperatures ≤740℃. （5）After annealing at 750 ℃/180 s intense V （ C, N） precipitation （ mean diameter 7.4 nm） was observed in the ferrite phase whereas precipitates were scarce in martensite （austenite） and much larger （ mean diameter 13.4 nm）. （6）The increase in tensile strength with martensite fraction of the reference al- loy was - 16 MPa/%. However, the vanadium alloy showed a much lower sensitivity to martensite content （ -4 MPa/% ） due to grain refinement and selective strengthening of the ferrite phase, and actually be- came softer than the reference steel at martensite fractions 〉 45%. At iso-tensile strength the fracture strain and hole expansion coeflqcient of the V alloy showed some improvement over the reference steel, however the gains were much smaller than those obtained by tempering.
出处
《钢铁钒钛》
CAS
北大核心
2017年第4期94-104,共11页
Iron Steel Vanadium Titanium
关键词
DP钢
AHSS
超细晶
钒微合金化
DP steels, AHSS,ultra-fine grains, vanadium microalloying
