热回复过程高强耐候钢Q450NQR1的高温力学性能

在热回复条件下,采用Gleeble-1500D热/力模拟实验机,研究测试了高强耐候钢Q450NQR1(/%:0.05～0.10C、0.30～0.50Si、0.80～1.00Mn、≤0.020P、≤0.008S、0.20～0.40Cu、0.15～0.35Ni、0.40～0.60Cr)200mm×1 350 mm铸坯试样在700～1 000℃,热拉伸应变率5×10^-3 s^-1时的强度、塑性模量和断面收缩率。结果表明,随温度下降铸坯塑性模量(硬化系数)和强度增加,800℃时铸坯的强度随温度的变化速率出现明显转变;925～700℃时铸坯断面收缩率≤60%;为保证铸坯质量,在矫直过程铸坯表面温度应≥950℃。

Elevated Temperature Mechanical Properties of High Strength Weathering Steel Q450NQR1 in Thermal Cycle Process

In thermal cycle condition,strength,plastic modulus and reduction of area high strength weathering steel Q450NQR1 200 mm×1350 mm casting slab（/%:0.05～0.10C,0.30～0.50Si.0.80～1.00Mn,≤0.020P,≤0.008S,0.20～0.40Cu,0.15～0.35Ni,0.40～0.60Cr） with heat tensile strain rate 5×10^-3s^-1 at 700～1 000℃have been studied and measured by using Gleeble-1500D thermo-mechanical simulator.Results show that with decreasing temperature the plastic modulus（hardening coefficient） and strength of casting slab increase,the change rate of strength of slab with temperature obviously alters at 800℃;the reduction of area of slab at 925～700℃is≤60%;in order to ensure the quality of slab,during straightening process the surface temperature of slab should be controlled≥950℃.