随着大型挖掘机中厚板焊接需求的增长,提升中厚板焊接效率愈发关键。以30 mm厚Q355D低合金钢为对象,采用Ø1.2 mm ER50-6焊丝进行多层多道混合气体保护焊,对比分析了两种不同热输入焊接工艺参数(WP-01和WP-02)对焊接接头组织及力学...随着大型挖掘机中厚板焊接需求的增长,提升中厚板焊接效率愈发关键。以30 mm厚Q355D低合金钢为对象,采用Ø1.2 mm ER50-6焊丝进行多层多道混合气体保护焊,对比分析了两种不同热输入焊接工艺参数(WP-01和WP-02)对焊接接头组织及力学性能的影响。结果表明,两种参数下焊缝成形良好,但组织和性能存在差异。WP-01低热输入条件下,焊缝区组织主要为细小的铁素体和贝氏体,过热区出现少量马氏体,晶粒细小;WP-02高热输入条件下,焊缝区贝氏体含量增加,过热区形成粗大铁素体、珠光体和魏氏组织,晶粒粗化。WP-01和WP-2焊接接头均具有较好的抗拉性能,屈服强度和抗拉强度均满足要求。WP-01试样因晶粒细小,冲击韧性显著高于WP-02。然而,WP-01试样在弯曲试验中焊缝根部出现裂纹,不符合合格标准;WP-02试样则无裂纹出现,满足要求。平均抗拉强度为532.5 MPa,WP-02为530 MPa,屈服强度最低值均为360 MPa,焊接接头抗拉性能满足要求。WP-01焊接接头硬度高于WP-02,主要原因是WP-02热输入更高,冷却速度更慢,淬硬倾向降低。综合考虑各项性能指标,大电流焊接工艺WP-02采用高焊接热输入,在保证焊接接头力学性能的同时,显著提高了焊接效率,更适用于Q355D中厚板焊接工艺。展开更多
Q355钢是中厚板领域中重要的低合金结构钢,其含碳量为0.12%~0.20%,具有良好的强度、韧性、可塑性和抗腐蚀性。钢板角部裂纹是中厚板生产中的一个常见问题,严重影响了产品的质量和使用性能,进而影响中板厂成材率。本文针对厚度8~20 mm Q3...Q355钢是中厚板领域中重要的低合金结构钢,其含碳量为0.12%~0.20%,具有良好的强度、韧性、可塑性和抗腐蚀性。钢板角部裂纹是中厚板生产中的一个常见问题,严重影响了产品的质量和使用性能,进而影响中板厂成材率。本文针对厚度8~20 mm Q355B钢板出现的角部裂纹的问题,采用金相观察形貌结合电子背散射衍射(EBSD)技术观察了晶粒尺寸和取向,探究了角部裂纹的微观组织演变特点,分析引起角裂的主要原因,提出了改善措施,并进行了生产性跟踪验证。结果表明:无角裂试样的晶粒组织均匀;有角裂试样的裂纹主要分布在表层及皮下,深度为0.1~0.5 mm,裂纹面晶粒粗大,存在明显的铁素体和再结晶组织。基于微观组织分析,确定中间坯厚度对角裂的影响较为严重,对于较小厚度的钢板,调整中间坯厚度影响不大,可适当增加精轧道次,减小角裂发生率。展开更多
To improve the weld formation of underwater-welded Q355B steel and enhance its corrosion resistance,this study introduced pulsed laser welding technology into local dry underwater welding process,building upon continu...To improve the weld formation of underwater-welded Q355B steel and enhance its corrosion resistance,this study introduced pulsed laser welding technology into local dry underwater welding process,building upon continuous laser welding process.A systematic investigation was carried out covering process exploration,weld morphology,microstructure,and comprehensive properties.The results indicate that the pulsed laser weld seam exhibited a distinct ripple pattern on the surface,along with significantly less spatter compared to continuous laser weld seam.Both the weld penetration depth and weld bead width showed a decreasing trend with increasing pulse frequency.The weld metal was primarily composed of ferrite and martensite phases.As the pulse frequency increased,the ferrite content first rose and then declined,reaching a maximum of 39%at 80 Hz.The microhardness and tensile strength of the weld metal were both higher than those of the base material,and all tensile specimens fractured within the base metal during testing.Furthermore,the elongation initially increased and then decreased with rising pulse frequency.The weld produced at 80 Hz achieved the highest elongation of 23.1%,which was 8.9% higher than that of the continuous laser weld seam and reached 93.9% of the base material.Electrochemical corrosion tests revealed that the weld produced at 80 Hz exhibited the best corrosion resistance,reaching 67.0% of that of the base material,while the continuous laser weld seam attained only 47.3% of the base material.This study provides critical theoretical and data support for the process optimization and application of local dry underwater laser welding in the fabrication of marine engineering structures.展开更多
文摘Q355钢是中厚板领域中重要的低合金结构钢,其含碳量为0.12%~0.20%,具有良好的强度、韧性、可塑性和抗腐蚀性。钢板角部裂纹是中厚板生产中的一个常见问题,严重影响了产品的质量和使用性能,进而影响中板厂成材率。本文针对厚度8~20 mm Q355B钢板出现的角部裂纹的问题,采用金相观察形貌结合电子背散射衍射(EBSD)技术观察了晶粒尺寸和取向,探究了角部裂纹的微观组织演变特点,分析引起角裂的主要原因,提出了改善措施,并进行了生产性跟踪验证。结果表明:无角裂试样的晶粒组织均匀;有角裂试样的裂纹主要分布在表层及皮下,深度为0.1~0.5 mm,裂纹面晶粒粗大,存在明显的铁素体和再结晶组织。基于微观组织分析,确定中间坯厚度对角裂的影响较为严重,对于较小厚度的钢板,调整中间坯厚度影响不大,可适当增加精轧道次,减小角裂发生率。
基金supported by the National Natural Science Foundation of China(Grant number U23A20625,U2141216,52375334)the Science and Technology Planning Project of Nansha District(Grant number 2025ZD003)the Science and Technology Program of Guangdong Province(Grant number 2023B1515250003).
文摘To improve the weld formation of underwater-welded Q355B steel and enhance its corrosion resistance,this study introduced pulsed laser welding technology into local dry underwater welding process,building upon continuous laser welding process.A systematic investigation was carried out covering process exploration,weld morphology,microstructure,and comprehensive properties.The results indicate that the pulsed laser weld seam exhibited a distinct ripple pattern on the surface,along with significantly less spatter compared to continuous laser weld seam.Both the weld penetration depth and weld bead width showed a decreasing trend with increasing pulse frequency.The weld metal was primarily composed of ferrite and martensite phases.As the pulse frequency increased,the ferrite content first rose and then declined,reaching a maximum of 39%at 80 Hz.The microhardness and tensile strength of the weld metal were both higher than those of the base material,and all tensile specimens fractured within the base metal during testing.Furthermore,the elongation initially increased and then decreased with rising pulse frequency.The weld produced at 80 Hz achieved the highest elongation of 23.1%,which was 8.9% higher than that of the continuous laser weld seam and reached 93.9% of the base material.Electrochemical corrosion tests revealed that the weld produced at 80 Hz exhibited the best corrosion resistance,reaching 67.0% of that of the base material,while the continuous laser weld seam attained only 47.3% of the base material.This study provides critical theoretical and data support for the process optimization and application of local dry underwater laser welding in the fabrication of marine engineering structures.
