304L/Q235B不锈钢层状复合板热处理工艺优化研究

Investigation on Heat Tretment Process Optimization of 304L/Q235B Stainless Steel Clad Plates

采用爆炸焊接法制备304L/Q235B不锈钢层状复合材料。为确定最佳热处理工艺制度,试验设计了4种热处理工艺。通过SEM和EDX能谱观察和分析304L/Q235B界面微观组织及元素扩散情况。采用显微硬度试验检测界面加工硬化现象改善程度,结果表明,在不同热处理工艺下,复合材料界面结合良好无分层,但在热处理的保温温度为620~700℃的条件下,复合材料界面附近区域发生Fe或Cr元素的扩散,保温温度达到700℃时元素扩散程度最大,且此时Q235B侧近界面区域晶粒尺寸最大,达到9~14μm。当热处理工艺的保温温度为660℃时,304L/Q235B加工硬化现象得到了明显改善,且能保证钢板硬度较高。当保温温度为660℃时,热处理后试样的晶间腐蚀试验结果显示,试样具有良好耐蚀性,未发生腐蚀。因此,保温温度为660℃是304L/Q235B复合材料的最佳热处理工艺。

304L/Q235B clad plates were prepared by explosive welding.In order to determine the best heat treatment process system,four kinds of heat treatment processes were designed.SEM and EDX were used to observe and analyze the microstructure and element diffusion of the 304L/Q235B interface.The microhardness test was used to analyze the improvement degree of work hardening phenomenon.The results show that the interface of the composite is well bonded without delamination under different heat treatment processes.However,with holding temperature of 620-700℃,the diffusion of Fe or Cr elements occurs near the interface of the 304L/Q235B clad plate,and the element diffusion degree is the largest with holding temperature 700℃.And the grain size near the interface of Q235B side is the largest(9-14μm).The process with holding temperature 660℃can decrease the work hardening degree of 304L/Q235B and keep the high hardness of steel plate.When the insulation temperature is 660℃,the results of the intercrystal corrosion test of the sample after heat treatment show that the sample has good corrosion resistance and the corrosion does not occur.Therefore,an insulation temperature of 660℃is the optimal heat treatment process for 304L/Q235B clad plates.