HTP工艺生产的700 MPa级中厚板的组织与性能

 研究了高Nb超低碳贝氏体钢在HTP工艺条件下轧态、回火态的组织与力学性能。采用的合金成分（质量分数）为：C 0.05%、Mn 1.85%、Nb 0.1%左右，其余合金元素有Cu、Ni、Cr、B等。进行了热模拟研究、实验室冶炼轧制和工业试制。试验结果表明，第二阶段开轧温度、冷却速度和轧后高温回火工艺对钢的组织、析出物的形态和数量有明显影响。采用合适的HTP工艺与轧后高温回火相结合，能够生产出屈服强度达到700 MPa级别的高强度、高韧性钢板。

Study of Microstructure and Performance of Medium and Heavy Plate of 700 MPa Grade High Strength Steel by HTP

The microstructure and performance of high Nb ULCB steel under the condition of as rolled and tempered were researched by HTP. The chemical compositions of the steel contained about C 0.05%、Mn 1.85%、Nb 0.1% and other elements such as Cu、Ni、Cr、B and so on. The thermal simulation, smelting and rolling in laboratory and industrial trial were carried out. These experimental results indicated that the secondary started rolling temperature, cooling rate and tempered process after rolling had the obvious effects on the microstructure, the shape and number of precipitates of the steel. By combined appropriate HTP process with tempered procedure after rolling, the steel grade with the yield strength 700 MPa and high strength and high toughness could be obtained.