1、造口：单个造口回波高度低，波形为单缝，比较稳定。 从各个方向检测，反射波大致相同，但探头稍微移动一点，就会在密集的孔隙中出现一簇反射波，波高随孔隙大小而变化。 造成此类缺陷的主要原因是焊材未在规定温度下干燥、焊条镀层变质、焊芯腐蚀、焊丝未清洗干净、手工焊接时电流过大、 弧线过长； 埋弧焊时电压过高。 或者网络电压波动太大； 气体保护焊时保护气体纯度低。 如果焊缝中存在气孔，不仅破坏了焊缝金属的致密性，还会降低焊缝的有效截面积，降低力学性能。 特别是有链孔时，弯曲和冲击韧性会明显降低。 . 防止此类缺陷的措施是：不要使用涂层有裂纹、剥落、变质和生锈的焊条，生锈的焊丝只能在除锈后使用。 所用焊接材料应在规定温度下干燥，坡口及两面应清洗干净，并选择合适的焊接电流、弧压和焊接速度。
2、夹渣：点状夹渣的回波信号与点状气孔相似。 条状夹渣的回波信号多为低幅度的锯齿波，波形多为树枝状。 主峰边缘有小峰，探头平移幅度不等。 ，当从各个方向检测时，反射波的幅度是不同的。 产生此类缺陷的原因有：焊接电流过小、速度过快、熔渣来不及上浮、焊边及各层焊缝清理不干净、原材金属的化学成分和 焊接材料不当，硫、磷含量较高。 等待。 预防措施包括：正确选择焊接电流，焊件坡口角度不宜过小，焊前必须清理坡口，多层焊时必须逐层清除焊渣； 运输角的焊接速度应合理选择。
3、不完全穿透：高反射率和高波幅。 探头平移时，波形比较稳定，在焊缝两侧探伤时，可以得到大致相同的反射波幅值。 此类缺陷不仅降低了焊接接头的力学性能，而且在未完全熔透的间隙和端部形成应力集中点，往往在加载后造成裂纹，是一种危险的缺陷。 造成这种情况的原因一般是：坡口纯边间隙太小，焊接电流太小或带钢速度太快，坡口角度小，带钢角度太小。 错了，电弧就吹了。 预防措施包括：合理选择坡口类型、装配间隙和正确的焊接工艺。
4、不熔断：探头平移时，波形比较稳定。 两侧检测时，反射波幅度不同，有时只能从一侧检测。 原因：坡口不干净，焊接速度太快，电流过小或过大，电极角度不对，电弧吹出等。预防措施：正确选择坡口和电流，清洁 坡口、正确操作防止焊接偏差等
5、裂纹：回波高度大，波幅宽，会有多个波峰。 当探头平移时，反射波的幅度不断变化。 当探头旋转时，波峰上下移动。 裂纹是最危险的缺陷之一。 除了降低焊接接头的强度外，裂纹的末端是一个尖销的缺口。 焊件加载后引起应力集中，成为结构断裂的起点。 裂纹分为三种类型：热裂纹、冷裂纹和再热裂纹。 产生热裂纹的原因是：焊接时熔池冷却速度很快，造成偏析； 焊缝受热不均匀会产生拉应力。 预防措施：限制母材和焊材中易偏析元素和有害杂质的含量，主要是限制硫含量，提高锰含量； 增加电极或助焊剂的碱度，以降低杂质含量，提高偏析程度； 改进焊接结构形式，采用合理的焊接顺序，提高焊缝收缩时的自由度。
英斯特力仪器是一家集研发、生产及销售于一体的 影像测量仪，拉力试验机, 硬度计 ,探伤仪, 粗糙度仪, 测厚仪, 金相设备厂家, 致力于为客户提供更好的检测仪器。
1. Stomata: the echo height of a single stomata is low and the waveform is single slit, which is relatively stable. From each direction detection, reflection wave is roughly the same, but a little move probe will disappear, dense pores will appear a cluster of reflection wave, wave height with the size of pores and different, when the probe for fixed point rotation, there will be the phenomenon of up and down. The main reasons for such defects are that welding materials are not dried according to the specified temperature, electrode skin deterioration off, welding core corrosion, welding wire cleaning is not clean, manual welding current is too large, the arc is too long; When submerged arc welding voltage is too high or network voltage fluctuation is too large; Gas welding protection gas purity low. If there are pores in the weld, it not only destroys the density of the weld metal, but also reduces the effective cross-sectional area of the weld and reduces the mechanical properties, especially when there are chain pores, the bending and impact toughness will be significantly reduced. The measures to prevent this kind of defects are: do not use the coating cracking, peeling, deterioration and welding core corrosion electrode, rusty wire must be removed rust before use. The welding materials should be dried at the specified temperature, the groove and both sides should be cleaned, and appropriate welding current, arc voltage and welding speed should be selected.
2. Slag trap: the dotted slag trap echo signal is similar to the dotted porosity, and the strip slag trap echo signal is zigzag with low amplitude, and the waveform is dendritic. There are small peaks on the edge of the main peak. The reasons for this kind of defects are: welding current is too small, too fast, slag too late to float, welding edge and each layer of weld cleaning is not clean, the metal and welding material chemical composition is improper, containing sulfur, phosphorus and so on. Prevention measures are: the correct selection of welding current, welding parts of the groove Angle is not too small, the groove must be cleaned up before welding, multi-layer welding must be layer upon layer to remove welding slag; And reasonable selection of transport Angle welding speed.
3, incomplete welding: high reflectivity, high amplitude, the probe translation, waveform is more stable, in both sides of the weld can get roughly the same reflection amplitude. This kind of defect not only reduces the mechanical properties of the welded joint, but also forms stress concentration point in the gap and end of the incomplete welding, which often causes cracks after loading, and is a kind of dangerous defect. The reasons are generally as follows: too small pure edge clearance of groove, too small welding current or too fast strip moving speed, small groove Angle, incorrect strip moving Angle and arc blowing. The prevention measures include reasonable selection of groove type, assembly clearance and correct welding process.
4, not fused: the probe translation, waveform is more stable, both sides of the detection, reflection amplitude is different, sometimes only from one side to explore. The causes: the groove is not clean, the welding speed is too fast, the current is too small or too large, the Angle of the electrode is not right, the arc blowing. Prevention measures: correct selection of groove and current, groove clean, correct operation to prevent welding deviation.
5, crack: echo height is large, wave width is wide, there will be multiple peaks, the probe translation reflected wave continuously appear amplitude changes, when the probe turns, the peak is staggered up and down phenomenon. Crack is one of the most dangerous defects, in addition to reducing the strength of the welded joint, but also because the end of the crack is the notch of the pin, welded parts after bearing, resulting in stress concentration, become the origin of structural fracture. There are three kinds of cracks: hot crack, cold crack and rehot crack. The reasons for the hot crack are as follows: the cooling speed of the molten pool is very fast during welding, resulting in segregation; Uneven heating of weld produces tensile stress. Prevention measures: limit the content of segregation elements and harmful impurities in base metal and welding materials, mainly limit the content of sulfur, improve the content of manganese; Improve the alkalinity of the electrode or flux to reduce the impurity content and improve the degree of segregation; Improve the welding structure and adopt a reasonable welding sequence to improve the degree of freedom of weld shrinkage.
客服1 