首页|大热输入条件下氮含量对低碳Mo-V-Ti-B微合金钢粗晶热影响区组织与冲击韧性的影响

大热输入条件下氮含量对低碳Mo-V-Ti-B微合金钢粗晶热影响区组织与冲击韧性的影响

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采用Gleeble研究了大热输入条件下,氮含量对低碳Mo-V-Ti-B微合金钢焊接粗晶热影响区组织和冲击韧性的影响.结果表明,在100 kJ/cm热输入条件下,85 N、110 N和144 N试验钢粗晶热影响区-20 ℃冲击功分别为186 J、97 J和57 J.随着试验钢中氮含量的增加,试验钢粗晶热影响区冲击功逐渐降低.当氮含量从85 ppm增加至110 ppm时,低碳Mo-V-Ti-B微合金钢焊接粗晶热影响区组织由块状铁素体+大量针状铁素体转变为块状铁素体+少量的针状铁素体,组织发生粗化,故粗晶热影响区冲击功降低.当氮含量从110 ppm进一步增加至144 ppm时,粗晶热影响区组织由块状铁素体+少量的针状铁素体转变为块状铁素体+珠光体,虽然块状铁素体晶粒发生细化,但是粗晶热影响区组织中的"硬相"珠光体的含量增加,并且珠光体尺寸较大,在冲击试样变形过程中"硬相"珠光体与基体形变不协调,从而导致裂纹的萌生,造成冲击功进一步下降.
EFFECT OF NITROGEN CONTENT ON MICRO-STRUCTURE AND IMPACT TOUGHNESS OF COARSE CRYSTAL HEAT AFFECTED ZONE OF LOW CARBON Mo-V-Ti-B MICRO-ALLOYED STEEL UNDER HIGH HEAT INPUT CONDITION
The influence of nitrogen content on the area of thermal impact zone of low-carbon Mo-V-Ti-B micro-alloy steel was studied by Gleeble.The results show,under the condition of 100 kJ/cm heat input,the impact energies in the-20 ℃ HAZ of 85N,110N and 144N test steels are 186 J,97 J and 57 J,respectively.With the increase of nitrogen content in the test steel,the impact work of the test steel decreases gradually.When the nitrogen content increased from 85 ppm to 110 ppm,the thermal affected area of welding low-carbon Mo-V-Ti-B micro-alloy steel changed from massive ferrite+a large amount of needle ferrite to a small amount of needle ferrite,and the tissue coarsened,so the impact work in the thermal affected area of coarse ferrite was reduced.When the nitrogen content further increased from 110 ppm to 144 ppm,coarse crystal thermal influence area organization from massive ferrite+a small amount of needle ferrite into massive ferrite+beads,although bulk ferrite grain refinement,but the"hard phase"pearlite content increases in tissue,and the size of the body is larger,"hard phase"beads and matrix in the impact sample deformation deformation of uncoordinated,resulting in crack initiation,causing impact work further decline.

nitrogen contenthot heat inputweldingrough crystalthermal influence areaimpact toughnesspearlite

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南京钢铁股份有限公司,江苏南京 210035

氮含量 大热输入 焊接 粗晶 热影响区 冲击韧性 珠光体

2024

河北冶金
河北省冶金学会

河北冶金

影响因子:0.124
ISSN:1006-5008
年,卷(期):2024.(3)
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