高密度脉冲电流处理改善1Cr13Mn13钢力学性能

研究了普通热处理工艺以及在此基础上进行高密度脉冲电流(EP)处理对1Cr13Mn13钢力学性能的影响.结果表明,普通"退火"(AF)或者"同溶淬火+回火"(SOT)热处理工艺对1Cr13Mn13钢力学性能的影响比较有限;而在SOT处理的基础上,对样品进行一定强度的EP处理,可以使材料的抗拉强度由(1250±10)MPa增加到1400 MPa,延伸率由(20±1)%提高到53%.在EP处理过程中,马氏体相在快速升温过程中转变成奥氏体相,新生成的奥氏体相在随后的快速降温过程中又转变成为比初始马氏体相更细小的马氏体板条结构.这一细化结构在提高材料抗拉强度的同时,也大幅度提高了材料的塑性.

IMPROVEMENT OF MECHANICAL PROPERTIES OF STEEL 1Cr13Mn13 BY ELECTROPULSING WITH HIGH DENSITY

Steel 1Cr13Mn13 was treated by electropulsing (EP) with high density after anneal-ing+furnace cooling (AF) or solution+oil quenching+tempering (SOT). Tensile experiments show that the mechanical properties of the sample treated by SOT+EP process with a maximum current intensity about 8.46 kA/mm~2 were greatly improved, compared with the sample only treated by SOT process, its tensile str ength and elongation increased from (1250±10) Mpa and (20±1)% to 1400 Mpa and 53%, respectively. Metallographs show that the equiaxed grains formed under high temperature solid solution treatment were remained in both the SOT and SOT+EP samples. But the coarse lamellar martensite in the SOT sample was greatly refined after EP treatment. As the samples were treated by EP treatment, they successively underwent a rapidly "heating-cooling" process with a heating time less than 0.001 s and a cooling time less than 0.6 s, resulting in a successive phase transformation of α'→γ→ α'. The lamellar α' martensites formed during rapidly cooling process have more refined size than that of the primary martensite laths, which further enhanced the tensile ductility and tensile strength of steel 1Cr13Mn13. Moreover, the maximum value of current intensity for each EP treatment can also influence the mechanical properties of the samples by controlling the amount of thc α' phase in the transformation. A highcr current intensity usually produces much more amount of α' phase with smaller lamellar size and the mechanical properties of the samples are more improved. But if the maximum current intensity is much higher than an optimal range about 8.30-8.46 kA/mm~2, the sample is overheated and the mechanical properties will be lowered.