预应变量对超低碳烘烤硬化(ULC-BH)钢硬化性能的影响

测定了ULC-BH钢1 mm退火冷轧钢板(/%:0.002C,0.008Si,0.60Mn,0.043P,0.009S,0.031Al,0.071Ti)经2%~10%预应变,170℃20 min烘烤后的烘烤硬化(BH)值,通过内耗实验获得不同应变时效下的内耗谱线,利用X射线衍射技术测定位错密度,研究了Cottrell气团对ULC-BH钢烘烤硬化性能的影响。结果表明,随预应变量增加,ULC-BH钢的BH值增大;随预应变量增加,Snoek峰逐渐降低,而SKK峰逐渐升高;经2%、6%和10%预应变,位错密度增大,分别为3.9×10¹⁰/cm~2,8.4×10¹⁰/cm²和6.8×10¹¹/cm²,相应的Cottrell气团密度逐渐减小。

Effect of Prestrain on Bake Hardening property of Ultra-Low Carbon Bake Hardening (ULC-BH) Steel

The bake hardening values ( BH) of ULC-BH steel 1 mm annealed cold rolled sheet (/%： 0. 002C, 0. 008Si, 0. 60Mn, 0. 043P, 0. 009S, 0. 031 Al, 0.017Ti) with prestraining by 2% ~ 10% and baking al 170 °C for 20 min have been measured, and the effect of Cottrell atmosphere on bake hardening property of ULC-BH sleet is studied by internal friction test getting internal friction spectrum curves at different strain ageing and using X-ray diffraction technique measuring dislocation density. Results show that with increasing prestrain the BH value of ULC-BH steel increases ； and with increasing prestrain the Snoek peak gradually reduces while SKK peak gradually raise； with prestraining by 2%, 6% and 10% the dislocation density increases, and that respectively are 3. 9 x 10¹⁰/cm², 8. 4 x 10¹⁰/cm² and 6. 8 x 10¹¹/cm², while corresponding Cottrell atmosphere density gradually decreases.