60Mn钢高温力学性能研究

STUDY ON HIGH TEMPERATURE MECHANICAL PERFORMANCE OF 60Mn STEEL

在Gleeble-2000动态热／力模拟实验机上，采用凝固法对60Mn钢的高温力学性能进行了研究。测定了零塑性温度和零强度温度，在4×10^-4／s应变速率下，所测钢种在熔点至750℃之间存在两个脆性温度区域，即熔点至1250℃的第Ⅰ脆性温度区域和925～750℃的第Ⅲ脆性温度区域。在第Ⅲ脆性温度区域，γ单相区的铝、钛、铌以AlN和NbN等氮化物及γ＋α两相区先共析α相呈网膜状在γ晶界的析出是造成钢脆化的主要原因。通过控制钢中氮、铝含量，采用合理的二冷方式，提高钢种的内在质量。

This paper studies high temperature mechanical performance of 60Mn steel by methods of solidifying on Gleeble-2000 experimental machine. ZDT （zero ductility temperature） and ZST （zero strength temperature） have been determined. Under the strain rate of 4 × 10^-4/s, there exist two low ductility temperature regions for the tested within the temperature range from steel melting points to 750℃, i. e. Region Ⅰ from the melting points to 1300℃ and Region Ⅲ from 925℃ to 750℃. In Region Ⅲ, the ductility loss is mainly resulted from the precipitations of nitrides of Al, Nb, etc. at the austenite boundaries in single y phase temperature range and the formation of the film-like proeutectoid ferrites along the γ grain boundaries in γ＋α two-phase temperature range. By taking measures of precisely controlling steel N, Al concentrations and adopting reasonable secondary cooling pattern interior quality of steel will be advanced.