基于机器人焊接大赛复杂组合件的焊接工艺分析

采用OTC弧焊机器人进行复杂组合件的焊接,分析了组合件的结构特点和焊接技术要点。在此基础上制订了组合件焊接的组对工艺、焊接顺序和焊接工艺参数。针对组合件编程施焊难点进行了工艺优化,提出了解决焊接难点的方案,最终得到了焊缝成形美观、尺寸符合要求、密闭性能良好的组合件,对今后工业生产中同类组合件的机器人焊接具有一定的指导意义。     

焊接应用——焊接结构与设计

针对不锈钢焊接建立的专家系统。可对各类不锈钢按照不同的焊接方法进行焊接性分析,焊接人员可方便地查询到分析结果,同时还可以对系统提供的焊接性分析结果进行浏览、修改、添加、删除。焊接性分析可以为后续的焊接工艺设计打下良好的基础。     

《焊接技术与焊接工艺问答》

本书是一部综合性的普及读物，以“问答”这—通俗易懂的表现形式，对焊接技术、焊接工艺及相关知识作了全面系统的论述，共有422个问题。其内容包括：焊接材料、焊接工艺、焊接期去、焊接接头、焊接应力与应变、焊接电弧与焊接冶金、手工焊接操作技术、焊接相关电工知识、焊接技术装备、焊接质量检测、     

2205双相不锈钢的焊接性及焊接技术

对2205双相不锈钢的焊接性能进行了研究分析,对材料的焊接技术关键进行了介绍。     

两种常见焊接接头的机器人焊接工艺

采用弧焊机器人进行了8 mm厚板对接平位焊、6 mm厚板T形接头平角焊试验,重点分析了坡口根部间隙、焊枪角度、电弧电压、焊接电流和焊接速度对板对接打底层焊缝成形、背面焊缝宽度和余高的影响,以及焊接速度、电弧电压和焊接电流对T形接头焊缝成形、焊脚尺寸和凸度的影响。通过试验优化了焊接工艺参数,获得了正反面成形美观、熔合良好、焊缝宽窄和高低均匀的对接接头;试验测得对接接头背面焊缝宽度为4.04 mm,背面焊缝余高为0.17 mm,正面焊缝宽度为14.20 mm,正面焊缝余高为1.22 mm。采用优化后的焊接工艺参数对T形接头进行了焊接试验,角焊缝两焊趾区域熔合良好、焊缝平齐、焊缝表面微下凹,试验测得焊脚尺寸为6.8 mm。     

不锈钢焊接性分析与焊接工艺设计专家系统

针对不锈钢焊接建立的专家系统,可对各类不锈钢按照不同的焊接方法进行焊接性分析,焊接人员可方便地查询到分析结果,同时还可以对系统提供的焊接性分析结果进行浏览、修改、添加、删除.焊接性分析可以为后续的焊接工艺设计打下良好的基础.焊接工艺设计采用正向推理机制,根据焊接方法、母材及其厚度等条件推理出焊接所需的焊接工艺参数,最后生成工艺指导书.系统不但可以针对不同的焊接方法和待焊母材进行工艺查询,还可以针对设计日期和工艺编号进行工艺查询,而且具有修改、删除和添加焊接工艺参数的功能.     

不同焊接方法对导电铜排焊接接头质量的影响

针对铜排的焊接接头,采用氦气保护的TIG焊、氩气保护的TIG焊和感应钎焊三种焊接方法,通过焊接接头外观质量检验、宏观金相检验、焊接接头强度拉伸试验等方面的研究,采集了大量试验数据,并对试验数据进行了分析,确定采用感应钎焊进行铜排焊接,能获得满足设计要求的焊接工艺。     

焊接应用——焊接结构与设计

通过选用不同的焊材及不同的焊接参数，对低温材料09MnNiDR进行了一系列的工艺评定试验。指出了影响09MnNiDR焊接接头低温韧性的主要因素，并提出了焊接时应采取的工艺措施。表6     

焊接自动线和焊接机器人

用于球罐焊接的柔性导轨焊接机器人研究 针对大型球罐焊接的工程实践,开发出系列柔性轨道焊接机器人,实现球罐的全位置多道多层焊接;并针对研制过程中的难点对焊接机器人锁紧机构的设计、在线焊缝轨迹示教、在线全位置焊接参数控制、自主学习开放式专家系统进行详细说明。实践证明,该柔性导轨焊接机器人能够较好地完成复杂工件的多种焊缝的现场焊接,尤其是球罐全位置焊接的工艺要求。     

焊接自动线和焊接机器人

用于球罐焊接的柔性导轨焊接机器人研究 针对大型球罐焊接的工程实践,开发出系列柔性轨道焊接机器人,实现球罐的全位置多道多层焊接;并针对研制过程中的难点对焊接机器人锁紧机构的设计、在线焊缝轨迹示教、在线全位置焊接参数控制、自主学习开放式专家系统进行详细说明。实践证明,该柔性导轨焊接机器人能够较好地完成复杂工件的多种焊缝的现场焊接,尤其是球罐全位置焊接的工艺要求。     

Effects of Post-weld Heat Treatment on Microstructure,Mechanical Properties and the Role of Weld Reinforcement in 2219 Aluminum Alloy TIG-Welded Joints

In as-welded state, each region of 2219 aluminum alloy TIG-welded joint shows diff erent microstructure and microhardness due to the diff erent welding heat cycles and the resulting evolution of second phases. After the post-weld heat treatment, both the amount and the size of the eutectic structure or θ phases decreased. Correspondingly, both the Cu content in α-Al matrix and the microhardness increased to a similar level in each region of the joint, and the tensile strength of the entire joint was greatly improved. Post-weld heat treatment played the role of solid solution strengthening and aging strengthening. After the post-weld heat treatment, the weld performance became similar to other regions, but weld reinforcements lost their reinforcing eff ect on the weld and their existence was more of an adverse eff ect. The joint without weld reinforcements after the post-weld heat treatment had the optimal tensile properties, and the specimens randomly crack in the weld zone.     

冲压圆点连接机理初探

对冲压圆点连接的机理和圆点处的金相组织进行了分析。冲压圆点连接可分为4个阶段 ,即板料初压入阶段、冲压圆点成形初期阶段、冲压圆点形成阶段、保压阶段。由于被连接的板料在冲压连接圆点处受挤压 ,所以在材料的连接处产生压应力 ,提高了连接的抗疲劳强度。此外 ,对冲压圆点连接的特点、应用范围及影响因素进行了论述     

Simulation of 3-D Deformation and Material Flow During Roll Forging Process Using System of Oval-Round Groove

Basing on the analysis of the traits of the roll forging process, a system-model of computer simulation has been established. Three-dimensional rigid-plastic FEM has been used for the simulation of the deformation process in the oval and round pass rolling, including the entering, rolling, and separating stages. The analysis was conducted using the Deform-3D ver.5.0 code. The important information concerned with the deformation area characteristic, material flow, and velocity field has been presented. Otherwise,the location of the neutral plane in the deformation area was shown clearly.     

Quantitative Analysis of the Crystallographic Orientation Relationship Between the Martensite and Austenite in Quenching–Partitioning–Tempering Steels

The orientation relationships(ORs)between the martensite and the retained austenite in low-and medium-carbon steels after quenching–partitioning–tempering process were studied in this work.The ORs in the studied steels are identified by selected-area electron diffraction(SAED)as either K–S or N–W ORs.Meanwhile,the ORs were also studied based on numerical fitting of electron backscatter diffraction data method suggested by Miyamoto.The simulated K–S and N–W ORs in the low-index directions generally do not well coincide with the experimental pole figure,which may be attributed to both the orientation spread from the ideal variant orientations and high symmetry of the low-index directions.However,the simulated results coincide well with experimental pole figures in the high-index directions{123}_(bcc).A modified method with simplicity based on Miyamoto’s work was proposed.The results indicate that the ORs determined by modified method are similar to those determined by Miyamoto’method,that is,the OR is near K–S OR for the low-carbon Q–P–T steel,and with the increase of carbon content,the OR is closer to N–W OR in medium-carbon Q–P–T steel.     

A CUMULATIVE FATIGUE DAMAGE RULE UNDER THE ALTERNATIVE OF CORROSION OR CYCLIC LOADING

Fatigue damage increases with the applied loading cycles in a cumulative manner and the material deteriorates with the corrosion time. A cumulative fatigue damage rule under the alternative of corrosion or cyclic loading was proposed. The specimens of aluminum alloy LY12-CZ soaked in corrosive liquid for different times were tested under the constant amplitude cyclic loading to obtain S-N curves. The test was carried out to verify the proposed cumulative fatigue damage rule under the different combinations among corrosion time, loading level, and the cycle numbers. It was shown that the predicted residual fatigue lives showed a good agreement with the experimental results and the proposed rule was simple and can be easily adopted.     

The Electrochemical Behavior of Oceanic Microbiological Influenced Corrosion on Carbon Steel

The corrosion behavior of carbon steel in the medium of marine microorganisms was investigated by electrochemical impedance spectra, polarization curves, and so on. Experimental results showed that the corrosion potential of carbon steel moved in a negative direction in the unpurified marine microorganism solution, and the polarization style of the cathodic process did not change. The electrochemical impedance spectra showed that the impedance value of the electrode decreased in the medium with bacteria, which indicated that the existence of microorganism could accelerate the corrosion progress of carbon steel.     

Grain Size-Dependent Mechanical Properties of a High-Manganese Austenitic Steel

The effect of grain size on the mechanical properties of a high-manganese(Mn) austenitic steel was investigated via electron-backscattered diffraction, transmission electron microscope, X-ray diffraction, and tensile and impact tests at 25 °C and-196 °C. The Hall–Petch strengthening coefficients for the yield strength of the high-Mn austenitic steels were 7.08 MPa mm 0.5 at 25 °C, which increased to 14 MPa mm 0.5 at -196 °C. The effect that the grain boundary strengthening had on improving the yield strength at-196 °C was better than that at 25 °C. The impact absorbed energies and the tensile elongations were enhanced with the increased grain size at 25 °C, while they remained nearly unchanged at -196 °C. The unchanged impact absorbed energies and the tensile elongations were primarily attributed to the emergence of the micro-twin at -196 °C, which promoted the cleavage fracture in the steels with large-sized grains. Refining the grain size could improve the strength of the high-Mn austenitic steels without impairing their ductility and toughness at low temperature.     

Development of corrosion sensors for monitoring steel‐corroding agents in reinforced concrete structures

Corrosion sensors were devised to develop a system whereby the depth of chloride permeation from concrete surfaces can be monitored non‐destructively on a real‐time basis using such sensors embedded in cover concrete of reinforced concrete structures. The proposed corrosion sensors were subjected to accelerated corrosion in NaCl solutions, mortar specimens intrinsically containing chlorides, and mortar specimens impregnated with chloride solutions, while recording the changes in the resistance readings. The resistance of sensors increased as the degree of corrosion increased. The time to the first change in the resistance decreased and the corrosion degree and resistance increased as the chloride concentration increased and as the distance from mortar surfaces decreased. It was therefore confirmed that the corrosion sensors are capable of monitoring the depth of chloride permeation with sufficient accuracy.     

精密检测在轧机牌坊空间位置测量中的应用

轧机在长期使用中机架牌坊内各窗口接触面、机架底面均会产生不同程度的腐蚀和磨损,使机架与轧辊轴承座间隙逐渐增大,加剧牌坊衬板的磨损,不能保证牌坊的窗口尺寸,从而不能保证轧机的功能精度。通过对轧机设备进行高精度的空间位置检测,可以撑握轧机的位置参数,为保证轧机功能精度提供强有力的数据支撑,以便更有针对性地对轧机进行维护、维修,保证轧机的稳定运行。以某1 580 mm热轧板带生产线精轧机组设备空间位置测量为实例,详细介绍了采用全站仪和激光跟踪仪进行测量的准备工作、注意事项、施工步骤、数据分析及调整结果,有助于该技术的推广应用。     

Influence of Fe on Microstructure and Mechanical Properties in Pdoped Ni–Cr–Fe Alloys

The influence of Fe on the microstructure and mechanical properties of P-doped Ni–Cr–Fe alloys has been investigated.Results showed that increasing Fe content refined the dendrite microstructure and enhanced the solubility of P in as-cast alloys. The change of microhardness in different dendrite regions was attributed to the segregation of P atoms in solid solution state, which had strengthening effects. Increasing Fe contents from 15.2 to 60.7 wt% reduced the yield strength and tensile strength but had little influence on the elongation of alloys. The stress rupture life of alloys after heat treatment decreased with the increment of Fe contents, and the failure fracture modes transferred from transgranular to intergranular fracture mode. The change of fracture modes was due to the weakness of grain boundaries caused by the increment of Fe.In addition, the precipitation of M_(23)C_6 was believed to be related to the segregation of P toward grain boundaries, which led to the fluctuation of carbon and chromium atoms near the grain boundaries in alloys with low Fe contents. Consequently, the increment of Fe decreased the strength of matrix and changed the existence of P atoms and the precipitates at grain boundaries.