用力学试验方法对焊接件进行性能评定

通过对一管道焊接件性能评定工作中常规力学试验结果的分析 ,介绍了常规力学试验在焊接件性能分析中的重要性。如果条件允许 ,对一些相对重要的部件 ,应尽可能进行一些力学试验 ,以确保焊接件的安全运行。尤其是当遇到一些具体焊接问题或金相检查中出现了介于超标与未超标的组织情况时更应如此。     

薄板焊接型机车齿轮罩加工工艺的改进

通过实例分析，得出薄板焊接结构件自然时效周期远远小于实心件周期，并对其机理进行了分析。     

中国实验快堆栅板联箱焊接件与钠的相容性

在模拟中国实验快堆运行工况条件下，对用不同来源304不锈钢制造的栅板联箱焊接件进行试验研究，分析和测试在450℃钠中浸泡3000h后焊接件的晶间腐蚀状况及其力学性能变化。试验结果表明：在本试验条件下，焊接件试样的平均腐蚀速率均小于0.9mg/（m_²•h）；焊接件的焊接区及热影响区表面均未出现晶间腐蚀；试验前后，试样的屈服强度、抗拉强度及延伸率均无明显变化。     

工程机械也要“面子”——工程机械焊接件外观质量的保证

在商品竞争十分激烈的今天，市场已由过去的“卖方市场”转化为“买方市场”，客户在选择商品的时候，不仅对其内部质量和性能有所要求，而其外观质量也逐渐成为评价商品的又一重要标准。要从第一印象“征服”客户，是时下商家绞尽脑汁探讨的问题，工程机械也不例外。在保证了内部质量后，真正做到“表里如一”，还需对工程机械的主体框架结构——焊接件着手。     

焊接件毛坯尺寸基准的研究

分析了焊接件毛坯的特点,从减少机械加工余量、提高完工后零件加工面与非加工面之间的尺寸精度等方面提出焊接件毛坯尺寸基准选择应该遵循的原则;通过对矫正机摆动梁毛坯尺寸基准选择的综合分析比较,证明焊接件毛坯尺寸基准的合理选择对提高零件精度和节约原材料有重要作用。     

KThin-YOLOV7:轻量级的焊接件表面缺陷检测

针对目前市面主流焊接件表面缺陷的模型检测精度不高,模型复杂和不满足实时监测等问题,提出了一种基于YOLOV7-tiny改进得到的焊接件表面缺陷新型检测模型KThin-YOLOV7。首先,设计了基于模拟人类视觉感受野的EMA-BasicRFBC模块,更换YOLOV7-tiny模型的空间特征金字塔SPP模块,从而加强模型特征表达的性能。其次,以SlimNeck设计范式结构为基础设计了ThinNeck结构,并用其更换YOLOV7-tiny的NECK特征融合部分,减少模型的参数量和计算量的同时提高了模型的平均检测精度。最后,引入K-means++算法找出合适的锚框,并用FEIOU损失函数更换原模型的LOSS,进一步帮助模型优化目标框的位置和大小。KThin-YOLOV7相对原始YOLOV7-tiny模型的mAP提升了7.11％,达到87.64％,同时模型的参数量和计算量分别下降了11.14％和15.26％。实验结果表明,KThin-YOLOV7能够高效且准确地定位检测焊接件表面的缺陷。     

Evaluation of Cracking Resistance of Copper-Bearing Age Hardening Steel Weldment

The weldability of a low-carbon copper-bearing age hardening steel was evaluated using cracking suscepti- bility calculation, HAZ maximum hardness measurement, and Y-groove cracking evaluation test. The results show that the hardenability characteristics and cold cracking susceptibility of the steel are very low. The results also indicate that a crack-free weldment can be obtained during the welding of this type of steel even at an ambient temperature as low as -5 ℃ as well as in an absolute humidity lower than 4 000 Pa without any preheat treatment. A slight preheat treatment can prevent the joint from cracking when welding is carried out at lower ambient temperature or higher absolute humidity.     

16Mn钢焊接件疲劳裂纹扩展的微观特征研究

研究了在循环载荷作用下,16Mn钢焊接件疲劳裂纹的扩展情况.通过光学显微镜观察了裂纹扩展的微观特征,发现了裂纹在焊接结构不同部位的扩展路径方式并分析了显微组织对裂纹扩展的影响.裂纹在母材处为穿晶扩展,在热影响区和焊缝金属中的扩展为穿晶和沿晶混合型.     

Image segmentation of small defects in precision weldments with complex structure

In this paper, the X-ray nondestructive test method of small defects in precision weldments with complex structure was presented. To resolve the difficulty of defect segmentation in variable grey image, the image processing based on Visual Basic programming method was adopted. The methods of automatic contrast and partial grey stretch were used to enhance the X-ray detection image which has relatively low contrast, then automatic threshold method was carried out to segment the two high intensity zones, and weld zones which contain the small defects was extracted. Smoothing and sharpen processing were proceeded on the extracted weld zones, and small defects in X-ray detection image of weldments with complex structure were segmented by using the method of background subtraction in the end. The effects of raster were eliminated, and because of that the image processing was only proceeded on the extracted weld zones, the calculated speed using the above provided algorithm was improved.