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采用宏观形貌分析、金属流线观察、断口分析、金相及能谱等手段,分析了某钢厂生产的Q235B带钢裁剪焊管后出现焊缝开裂的问题。认为基体在连铸时内弧厚度方向1/4处存在的偏析和夹杂物,经加热焊接挤压后,破坏了焊缝表面的连续性,在应力作用下形成微裂纹,是造成焊管开裂的主要原因。通过优化冶炼工艺,降低锰硫比等措施使缺陷基本得到控制。 相似文献
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材质为Q345的热轧型钢在焊接过程中出现了开裂,导致了构件的报废。从焊缝组织成分、焊缝内应力、定位焊缝焊脚尺寸3个方面进行了分析,确认施焊过程中定位焊缝位置选择不正确、焊脚尺寸过小造成焊缝内部严重质量缺陷,从而导致焊缝开裂。 相似文献
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通过实验手段与用户旋压工艺分析,研究了Q345B车轮辐旋压成型过程中出现的开裂问题。结果表明:用户火切缺陷、旋压工艺参数设计不当及钢板表面氧化铁皮未去除干净是造成轮辐开裂的主要原因。采取了合理措施,优化了Q345B轮辐用钢板的化学成分,并对冶炼及轧制工艺的精确控制,有效的提高了Q345B车轮辐用钢板的性能指标,满足了客户的需求。 相似文献
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Q345B钢板在冷弯时开裂,对开裂钢板进行力学性能、化学成分、金相组织、非金属夹杂物等检测。结果表明:Q345B钢板开裂的裂纹源位于钢板厚度1/4处,开裂的主要原因是大量的硫化物夹杂和马氏体偏析带。 相似文献
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压扁试验是检验钢管质量的方法之一,通过分析压扁试验开裂原因来采取相应手段可解决焊接钢管压扁试验开裂问题。实验采用扫描电子显微镜(SEM)、能谱仪(EDS)和金相显微镜(OM)等设备对焊接钢管压扁试验开裂的原因主要进行两方面分析:金相分析和断口分析。金相分析可得出主要结论,断口分析验证金相分析得出最终结论。结果表明:焊接钢管压扁试验开裂的主要原因为焊接钢管内存在大量的硅酸盐类夹杂物,此类夹杂物属于高温塑性夹杂物,容易破坏基体的横向连续性,在压扁试验中可引起应力集中,促使裂纹的形成,导致钢管开裂。焊接钢管开裂的次要原因为试样存在带状组织且铁素体晶界处还分布着网状三次渗碳体,三次渗碳体塑性差,压扁时会进一步加剧裂纹的扩展。通过分析开裂的原因进而对焊接钢管生产工艺进行优化,经过钢包精炼炉(LF)精炼与控轧控冷技术可减少钢中夹杂物,进而改善焊接钢管压扁开裂问题,使钢管失效率下降,提高焊接钢管的质量。 相似文献
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大直径直缝焊管主要用于石油、天然气、水煤浆及各种液体的管道输送.鞍钢拥有丰富的宽厚板资源和优秀的技术人才,已具备了建设整套大直径直缝埋弧焊管机组的条件.对大直径直缝焊管的需求前景、主要生产工艺以及鞍钢建设大直径直缝埋弧焊管机组的可行性进行了探讨. 相似文献
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叙述了天铁集团运输部应用KD-286焊条进行焊修高锰钢辙叉的工艺过程。针对该技术应用中出现的夹碳、裂纹、未融合及未焊透等问题,从焊接工艺方面进行了分析探讨。通过待焊补辙叉的焊修表面处理、调控刨削速度,改进堆焊顺序、控制冷却速度、调整引弧方位等措施消除了该问题,提高了辙叉使用寿命,创造了经济效益。 相似文献
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对铝含量为2%、4%(质量分数,下同)的310S耐热钢板材采用手工氩弧焊(TIG)的焊接方法进行焊接,利用光学显微镜对焊缝的显微组织进行分析,利用电子探针(EMPA)分析焊接母材的元素分布,并对焊接接头进行室温和高温(800℃)力学性能测试。结果表明:不同铝含量的310S耐热钢板材焊接后的组织均良好,都没有宏观裂纹及夹杂等缺陷;铝元素的加入,抑制了焊接热影响区晶粒的异常长大,细化了晶粒;高铝310S的焊接板材与母材一样具有优良的室温力学性能和高温力学性能,加铝310S耐热钢具有良好的焊接性能。 相似文献
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《钢铁研究学报(英文版)》2016,(10):1104-1110
The mechanical properties of welded joints in resistance spot welding of DP780 steel were tested,and three dif-ferent types of welding cracks in welded joints were investigated by optical microscopy,scanning electron microscopy and electron back-scattered diffraction.Finally,the failure mode of the welded joints in shear tensile test was dis-cussed.It is found the shear tensile strength of welded joints can be greatly improved by adding preheating current or tempering current.The surface crack in welded joint is intergranular fracture,while the inner crack in welded joint is transgranular fracture,and the surface crack on the edge of the electrode imprint can be improved by adding prehea-ting current or tempering current.The traditional failure mode criterion advised by American Welding Society is no longer suitable for DP780 spot welds and the critical nugget size suggested by Pouranvari is overestimated. 相似文献
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Transformation induced plasticity (TRIP) steel exhibited high or rather high carbon equivalent (CE) because of its chemical composition, which was a particularly detrimental factor affecting weldability of steels. Thus the weldability of a TRIP steel (grade 600) containing (in mass percent, %) 0.11C-1. 19Si-1.67Mn was extensively studied. The mechanical properties and impact toughness of butt joint, the welding crack susceptibility of weld and heat affected zone (HAZ) for tee joint, control thermal severity (CTS) of the welded joint, and Y shape 60° butt joint were measured after the gas metal arc welding (GMAW) test. The tensile strength of the weld was higher than 700 MPa. Both in the fusion zone (FZ) and HAZ for butt joint, the impact toughness was much higher than 27 J, either at room temperature or at -20 ℃, indicating good low temperature impact ductility of the weld of TRIP 600 steel. In addition, welding crack susceptibility tests revealed that weldments were free of surface crack and other imperfection. All experimental results of this steel showed fairly good weldability. For application, the crossmember in automobile made of this steel exhibited excellent weldability, and fatigue and durability tests were also accomplished for crossmember assembly. 相似文献
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Modeling of the effects of surface-active elements on flow patterns and weld penetration 总被引:6,自引:0,他引:6
A mathematical model was developed to calculate the transient temperature and velocity distributions in a stationary gas tungsten
arc (GTA) weld pool of 304 stainless steels with different sulfur concentrations. A parametric study showed that, depending
upon the sulfur concentration, one, two, or three vortexes may be found in the weld pool. These vortexes are caused by the
interaction between the electromagnetic force and surface tension, which is a function of temperature and sulfur concentration,
and have a significant effect on weld penetration. For given welding conditions, a minimum threshold sulfur concentration
is required to create a single, clockwise vortex for deep penetration. When two metals with different sulfur concentrations
are welded together, the weld-pool shape is skewed toward the metal with a lower sulfur content. Detailed physical insights
on complicated fluid-flow phenomena and the resulting weld-pool penetration were obtained, based on the surface tension-temperature-sulfur
concentration relationships. 相似文献
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山东冶金机械厂在对25t转炉托圈裂纹的焊修中,采用手工电弧焊,焊接顺序为先修轴头再修盖板。焊前钻止裂孔,加拘束连接板,预热;焊接时采取多层多道、分段焊接的方法;焊后分别进行去应力退火和整体回火处理,使焊补焊缝及表面质量达到Ⅱ级。 相似文献
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A.K.Lakshminarayanan 《钢铁研究学报(英文版)》2009,16(5):66-0
The present investigation is aimed at to study the effect of welding processes such as shielded metal arc welding, gas metal arc welding and gas tungsten arc welding on tensile and impact properties of the ferritic stainless steel conforming to AISI 409M grade. Rolled plates of 4 mm thickness were used as the base material for preparing single pass butt welded joints. Tensile and impact properties, micro hardness, microstructure and fracture surface morphology of the welded joints have been evaluated and the results are compared. From this investigation, it is found that gas tungsten arc welded joints of ferritic stainless steel showed superior tensile and impact properties compared with shielded metal arc and gas metal arc welded joints and this is mainly due to the presence of finer grains in fusion zone and heat affected zone. 相似文献