Effects of Heat Input on Microstructure and Property of MAG Welded Joints of 10CrNi3MoV Steel
-
摘要: 为制定合理的焊接工艺，保证焊接质量，设置不同焊接热输入进行了10CrNi3MoV钢MAG焊接。采用微观组织分析、断口观察、力学测试等手段研究了焊接热输入对接头组织及性能的影响。结果表明，热输入较小时（E=11.0 kJ·cm-1、E=14.4 kJ·cm-1），焊缝组织以针状铁素体为主，并含有部分粒状贝氏体、先共析铁素体等；热输入较大时（E=18.1 kJ·cm-1），针状铁素体占比降低，粒状贝氏体、先共析铁素体等增多，组织粗化。随热输入的增大，粗晶区晶粒粗化，组织由板条马氏体逐步转变为板条贝氏体，板条界限模糊，并有粒状贝氏体出现；焊缝金属强度降低，冲击韧性先略有升高后显著降低，断裂形式由微孔聚缩型韧断变为准解理/韧性混合断裂。热输入E=14.4 kJ·cm-1时，焊缝组织以细密的针状铁素体为主，具有最佳强韧性匹配。
-
关键词:
- 10CrNi3MoV /
- 热输入 /
- 组织 /
- 性能 /
- 针状铁素体
Abstract: 10CrNi3MoV steel is welded by metal active gas welding (MAG) with different heat input. The effect of heat input on microstructure and mechanical property of the welded joints are investigated by means of microstructure analysis, fracture observation and mechanical tests. Results show that the microstructure of the welded metal is mainly acicular ferrite, with a certain amount of proeutectoid ferrite and granular bainite, when the heat input (E=11.0 kJ·cm-1, and E=14.4 kJ·cm-1) is low. When the heat input (E=18.1 kJ·cm-1) is high, the amount of acicular ferrite decreases, and the amount of proeutectoid ferrite and granular bainite significantly increase, and the microstructure coarsens. With the increase of heat input, the grain size of the coarse grained heat affected zone (CGHAZ) increases, and the microstructure transforms from lath martensite to lath bainite. The lath boundaries become blurred and the granular bainte emerges. The strength of the welded metal decreases, and the impact toughness increases slightly at first and then decreases significantly. The fracture mode changes from microporous polycondensation ductile fracture to quasi cleavage/ductile mixed fracture. When the heat input is 14.4 kJ·cm-1, the microstructure is mainly fine acicular ferrite and the welded joint has the best combination of strength and toughness.-
Keywords:
- 10CrNi3MoV /
- heat input /
- microstructure /
- property /
- acicular ferrite
-
-
[1] KANG J S, SEOL J B, PARK C G. Threedimen-sional characterization of bainitic microstructures in low-carbon high-strength low-alloy steel studied by electron backscatter diffraction[J]. Materials Characterization, 2013, 79:110-121.
[2] 秦华, 刘政军, 苏允海, 等. 热输入对BWELDY-960Q钢焊接接头组织性能的影响[J]. 焊接学报, 2015, 36(6):103-106. [3] 尚成嘉, 王学敏, 周召槿, 等. Mn-Mo-Nb-B低碳微合金钢中温转变组织的演化[J]. 金属学报, 2008, 44(3):287-291. [4] 何亮, 牛继承, 张玉祥. Mo元素对船用高强钢碱性焊条熔敷金属组织和性能的影响[J]. 材料开发与应用, 2017, 32(6):34-39. [5] 万响亮, 李光强, 吴开明. 低合金高强钢针状铁素体组织特征和形成机理[J]. 钢铁研究学报, 2016, 28(6):1-12. [6] SHIGESATO G, SUGIYAMA M. Development of in situ observation technique using scanning ion microscopy and demonstration of Mn depletion effect on intragranular ferrite transformation in low-alloy steel[J]. Journal of Electron Microscopy, 2002, 51(6):359-367.
[7] SHIM J H, BYUN J S, CHO Y W, et al. Mn absorption characteristics of Ti2O3 inclusions in low carbon steels[J]. ScriptaMaterialia, 2001, 44(1):49-54.
[8] WAN X L, WANG H H, CHENG L, et al. The formation mechanisms of interlocked microstructures in low-carbon high-strength steel weld metals[J]. Materials Characterization, 2012, 67:41-51.
[9] WAN X L, WEI R, WU K M. Effect of acicular ferrite formation on grain refinement in the coarse-grained region of heat-affected zone[J]. Materials Characterization, 2010, 61(7):726-731.
[10] 安同邦, 单际国, 魏金山, 等. 热输入对1000 MPa级工程机械用钢接头组织性能的影响[J]. 机械工程学报, 2014, 50(22):42-49. [11] CHENG L, WU K M. New insights into intragranular ferrite in a low-carbon low-alloy steel[J]. ActaMaterialia, 2009, 57(13):3754-3762.
[12] 曹志民, 张贵锋, 张建明, 等. Q690C粒状贝氏体钢MAG焊接头中M-A组元的演变及其对热影响区冲击韧度的影响[J]. 机械工程学报, 2014, 50(20):84-92. [13] WANG Z F, SHI M H, TANG S, et al. Effect of heat input and M-A constituent on microstructure evolution and mechanical properties of heat affected zone in low carbon steel[J]. Journal of Wuhan University of Technology-Mater Sci Ed, 2017, 32(5):1163-1170.
计量
- 文章访问数: 107
- HTML全文浏览量: 11
- PDF下载量: 27
下载:
