焊接发尘率测量装置及测控系统的研究

针对熔化极气体保护焊(GMAW)焊接发尘率的测量准确性问题,对焊接发尘率测量过程中涉及的信号检测和控制装置进行了研究,研发了一种焊接发尘率测量装置的测控系统,实现了对GMAW焊接过程中焊接电流、焊接电压和焊接速度等焊接工艺参数的准确测量或控制。通过对该测量系统的检测和控制过程的分析,设计了运动控制系统、抽滤系统和数据采集系统,建立了系统的控制时序;在LabVIEW平台上实现了对测量过程的实时监控,并完成了对检测数据的自动化采集、分析和存储。研究结果表明:该系统能够实现焊接工艺参数测量和控制的功能,测量精度和测量准确性均能满足设计要求。     

二氧化碳气体保护焊气体集中供气装置

二氧化碳气体保护焊具有变形小、焊接成本低、操作方便和焊缝成形美观等诸多优点,使之在焊接领域中迅速地占有一席之地。尤其在集装箱和汽车制造业中使用二氧化碳气体保护焊更为晋遍。目前二氧化碳气体使用量大的单位虽仍然依靠二氧化碳气瓶供给二氧化碳气体,但已感到钢瓶的运输、搬运、管理造成了压力,同时运输能力60％以上消耗在钢瓶的重量上,很不经济。若用一辆低温液体汽车槽车运输,然后充     

改进气体保护焊焊枪

我厂生产12V240)型精确机的水套,水套上体与套筒的圆周连接过去一直采用手工焊接。工作条件差,生产效率低,质量也不稳定。为此,我们设计制造了水套气体保护自动焊     

微型汽车焊装生产线CO2气体保护焊气体用量的分析

我公司CH1018B微型车焊装生产线上共有12台CO_2气体保护焊机,其目的是当由于微型车零件结构复杂或过大,采用焊钳点焊无法实现时,采用CO_2气体保护焊。这些焊机分别分布在4号、5号、16号、24号、28号工位,通过对焊机参数的调查,焊缝的测量,可以初步估算出焊装线CO_2用量。本文就是根据这个思路逐项分析,估算出CO_2气体用量。     

气体保护焊焊丝的选用分析

目前,随着市场竞争的日益激烈,各生产厂家为增强市场竞争力,越发强烈地追求提高生产效率、降低生产成本,气体保护焊的出现适应了这一社会需要,以高效、节能、操作简单、便于实现机械化和自动化等特点,现在已经在各行各业的生产制造中得到逐步的应用和推广[1]。而焊材的选择作为焊接工艺的重要组成部分,与产品的质量有着直接的关系,本文主要对使用气体保护焊制造产品时,对较为典型的碳素结构钢、合金结构钢以及不锈钢的气体保焊丝的选用进行相应的分析和叙述,希望能够对相关单位有所帮助。     

CO2气体保护焊供气方式的改进

我厂是生产广州牌大客车的,在客车生产中骨架的拼装是采用CO_2气体保护焊(以下简称CO_2焊)焊接的。采用CO_2焊接优点很多,但现在市场上CO_2气体供应的方式是用瓶装液化气体,这种供气方式用于单机作业是合适的,但用于大车间的多机大规模作业就不太理想了。因为客车骨架拼装的尺寸比较大,吊运时需要有较宽阔的空间,而在车间竖立的气瓶经常成了障碍     

中厚板二氧化碳气体保护焊焊接工艺

介绍了中厚板Q345结构钢二氧化碳气体保护焊焊接工艺，通过控制工艺参数及焊接工序，清除焊接变形、气孔等缺陷，提高焊缝一次成功率。     

CO2气体保护焊应用实例几则

一、CO_2焊在焊补大厚度灰口铸铁件上的应用 1983年我厂一台50t三用联合冲剪机冲床部位上悬臂,在使用中发生严重断裂性裂纹。裂纹总长500mm左右,严重地影响了生产正常进行。我们参阅了有关资料并结合本厂的实际情况,提出用CO_2焊方法焊补大厚度冲床     

混合气保护焊在阀门生产中的应用研究

叙述了采用熔化极氩弧焊工艺焊接铬镍奥氏体不锈钢易产生的缺陷及改进措施。研究证明，采用加有O2的氩气作保护气，HOCr20Ni10Ti作焊丝填充，A132焊条盖面可获理想焊接接头。     

螺旋焊管机组中成型机的设计及调型

介绍了螺旋焊管机组的组成和特点及成型机的结构及原理,并对成型机的调型进行了分析。     

A practical approach towards mathematical modeling of deposition rate during twin-wire submerged arc welding

The present paper deals with a shop floor applicable mathematical model for deposition rate during twin-wire submerged arc welding. The salient features of this model are (1) instead of melting rate, as modeled during past investigations, it quantifies the deposition rate, which is the actual outcome of the process and always remains smaller than the melting rate because of evaporation or spatters losses and (2) it estimates electrode extension in order to predict the deposition rate which makes the proposed model more practical than the models constituted with the help of experimental measurement of electrode extension. The model is more scientific than the simplified models where contact tube to work-piece distance has been considered as the electrode extension. A critical review of the relevant past investigation is given and a mathematical model is developed for deposition rate during the twin-wire welding with both the polarities, i.e., direct current electrode positive and direct current electrode negative. The model is calibrated using the results of 200 experimental runs and it is found to be very accurate with very high coefficient of regression and admissible standard error. The developed model is further validated with extra experimental runs. The practicality of the considered approach for prediction of deposition rate can further be used in future research for other consumable arc welding processes.     

Effect of shielding gas mixture on gas metal arc welding of HSLA steel using solid and flux-cored wires

In this work, gas metal arc welding of high strength-low alloy (HSLA) steel with solid- and flux-cored arc welding wires using different shielding gas compositions was performed. The composition of filler wire and shielding gas in gas metal arc welds of HSLA steel determines the inclusion characteristics, microstructure and mechanical properties. Thus, acceptable weld metal properties in HSLA steel using gas metal arc welding (GMAW) process could be achieved with the proper combination of filler wire and shielding gas composition.     

Feature extraction and dimensionality reduction of arc sound under typical penetration status in metal inert gas welding

Arc sound is well known as the potential and available resource for monitoring and controlling of the weld penetration status,which is very important to the welding process quality control,so any atten...     

Measurement and verification of transient injection flow rate of high pressure natural gas pulse injector

A high-pressure natural gas direct injection engine can achieve lean combustion and diffusion combustion of natural gas, which can reduce the emission level and improve power performance. However, the transient gas injection rate of the injector directly affects the combustion rate. In order to optimize engine performance, it is essential to focus on the technology used to measure the transient injection rate. Therefore, in this study, a method is developed to measure the transient flow rate of a high-pressure natural gas pulse injector. First, experiments were conducted to locate the optimum position for sensor installation, thereby ensuring the quality of the signal. Subsequently, a mass flow meter and schlieren imaging method was used to verify the injection mass and injection start/end timing. Finally, the common working conditions of a certain type of injector are measured. Results indicated that the test error of the cycle injection mass and injection start/end timing did not exceed 4% and 2.1%, respectively. As the injector energizing time increased, the injection rate curve changed from triangle to trapezoid. As the injection pressure increased, the injection start delay time decreased and end delay time increased. Measurement of the main and post injection strategy indicates that the main injection has a significant impact on the injection mass and injection rate curve for post injection. When the interval between the two injections is short, the injection rate curves merge. This increases the injection duration. The total injection mass of the main injection and post injection mass is found to be significantly higher than the sum of the two independent injections.     

An experimental and theoretical analysis on the application of stress-based forming limit criterion

In this paper, a detailed study on the stress-based forming limit criterion (FLSD) during linear and complex strain paths is developed. The calculation of stress-based forming limits based on experimental strain data is performed by using the method proposed by Stoughton [A general forming limit criterion for sheet metal forming. International Journal of Mechanical Sciences 2000;42:1–27]. By applying several combinations of different constitutive equations on the required plastic calculation, an analysis on the experimental forming stress limits is performed. The necking phenomenon is simulated by Marciniack–Kuczinsky (M–K) model using a more general code for predicting the forming limits. The selected materials are a bake-hardened steel (BH steel) and an AA6016-T4 aluminium alloy. Several yield criteria such as Von Mises isotropic yield function, quadratic and non-quadratic criterion of Hill (A theory of the yielding and plastic flow of anisotropic metals. Proceedings of the Royal Society of London 1948;A193:281–97; Theoretical plasticity of textured aggregates. Mathematical Proceedings of the Cambridge Philosophical Society 1979;85:179–91) and the advanced Barlat Yld96 yield function are used to show the influence of the constitutive law incorporated in the analysis on the stress-based forming limits. The effect of the hardening model on the FLSD is analysed by using two hardening laws, namely Swift law and Voce law. The influence of work hardening coefficient, strain rate sensitivity and the balanced biaxial yield stress on the theoretical FLSD is also presented. The effect of strain path changes on the stress-based forming limits is analysed. Some relevant remarks about stress-based forming limit criterion concept are presented.     

An arc stability evaluation approach for SW AC SAW based on Lyapunov exponent of welding current

Based on the experimental non-linear time series of welding current produced by Square Wave Alternating Current Submerged Arc Welding (SW AC SAW) at different frequency and duty cycle, the largest Lyapunov exponents of the welding system are numerically evaluated by the phase space reconstruction technique and the improved small-data method algorithm. The experimental and calculated results show that the largest Lyapunov exponent can describe the arc stability as a quantitative indicators at the process of Square Wave AC SAW. Further analysis proves that when the duty cycle of welding current is 0.5, the largest Lyapunov exponent reaches small values and the welding processes approach high steady states. When the welding current frequency is larger, the largest Lyapunov exponent reaches small values and the welding processes approach high steady states. When the welding current frequency is smaller, the system is at the unsteady mode and the largest Lyapunov exponent attains large values. Therefore, the welding current frequency is negatively correlated with the welding process stability.     

Study on wet gas online flow rate measurement based on dual slotted orifice plate

According to the current technical problems existing in gas and liquid flow measurement for wet gas production, the slotted orifice-couple flow meter was developed and the basic measurement principles for gas and liquid flow was presented. A new wet gas flow meter was developed based on the dual slotted orifice transducer. The flow characteristics of liquid flow through dual slotted orifice plate, the relationship of differential pressure between the dual slotted orifice plate, pressure, temperature, and flow rate of gas/liquid of different aperture ratio were studied. A mathematical measurement model was established to be applied in the flow meter measurement system with dual slotted orifice plate. The model was tested and calibrated by on-site field experiments in the China National Center of Metrology at Daqing Oil field. The results showed that the maximum measurement error of the gas and liquid flow was less than 10% and 15% respectively, when the Gas Volume Fraction (GVF) was greater than 90 vol%. The measurement accuracy of this industrial prototype can meet the requirements of well fluids.     

An intelligent approach for calculating natural gas compressibility factor and its application in ultrasonic flow meters

The current study presents an intelligent method for calculating natural gas compressibility factor. The method requires three easily measurable properties including pressure, temperature, and speed of sound as inputs. As sound speed could be measured with ultrasonic flow meters, temperature, and pressure with appropriate sensors, the real-time natural gas compressibility factor could be calculated easily. The presented method eliminates the high cost of determining compressibility based on measuring natural gas composition. Artificial Neural Network is employed to develop the method. The artificial neural network is trained in a way to accept pressure, temperature, and speed of sound as inputs. To train an artificial neural network, the 30,000 random datasets of natural gas compositions were utilized. To check the validity and accuracy of the developed artificial neural network, four different natural gas compositions are selected and the compressibility factor are compared with the GERG-2008 equation of state (as standard and accurate method for calculating natural gas properties) results. The results reported the average absolute percent deviation is less than 0.7% for the compressibility factor calculation by utilizing the proposed method.