钛合金激光焊接的气体保护与焊前清理

钛及钛合金以其许多独特的性能优势,目前已得到世界各国的普遍重视,并获得了广泛应用．这一方面证明了钛合金的巨大用途,另一方面也预示着钛合金材料开发研制的光辉前景．为进一步提高其质量,扩大其应用范围,对钛合金的各种加工处理工艺也正处于改进与完善之中． 本文概述了钛合金的焊接现状,提出了钛合金试件清理与气体保护的方案,自行设计加工了用于钛合金激光焊接的专用夹具和惰性气体保护拖罩,并提出了初步检验钛合金激光焊接接头质量的方法,对钛合金激光焊接的试验研究与工程实践会起到一定的促进作用．ｌ钛合金的焊接 通常情…     

高性能WNQ690钢气体保护焊试验研究

以WNQ690钢为研究对象,采用气保护焊接工艺,焊接线能量控制在15kJ／cm,WER70NH匹配WNQ690钢进行焊接,研究WNQ690钢焊接性能及焊接组织结构。接头抗拉强度为750MPa,冷弯性能优良,焊缝-40℃平均冲击功为137J,熔合线及热影响区冲击功均达到较高水平,焊接接头的HV10硬度在234-300之间,说明WNQ690钢淬硬倾向较小。WNQ690钢材的组织为回火贝氏体,焊接接头过热区组织为贝氏体,焊缝中含有较多的针状铁素体和少量的先共析铁素体,焊接热影响区的细小贝氏体组织使焊接热影响区具有较高的冲击韧性。     

低合金高强钢激光—电弧复合焊焊缝组织及性能研究

激光—电弧复合焊兼具表面成形较好、熔深较大的特点,在中厚板焊接中获得广泛应用,但激光复合焊时,焊缝冷却速率较快,焊缝淬硬倾向较强,在中厚板低合金高强钢焊接时应用受限.针对宝钢生产的BG890QL低合金高强钢进行激光—电弧复合焊接,研究焊缝组织的淬硬倾向,结果表明:激光—电弧复合焊接接头柱状晶组织特定生长方向明显,但焊缝中心和顶部存在等轴晶.室温和-40℃时,焊缝处的冲击功分别为58 J和40 J,热影响区的分别为147 J和66.5 J,冲击性能均能满足要求.激光—电弧复合焊低合金高强钢可以获得强韧性较好的焊缝及热影响区组织,满足工程应用需求.     

二氧化碳气体保护焊焊嘴用铜合金管材的研制

1 前言 二氧化碳气体保护焊焊嘴(以下简称焊嘴),是焊具中的一个十分关键的部件。它必须具有优良的电导率、导热率和较高的强度、硬度、耐磨性及高温软化特性等。为了解决被国家科委列为重点推广项目的这一课题,江苏省冶金研究所早于1986年就着手研制二氧化碳气体保护焊焊嘴用的合金管     

二氧化碳气体保护焊在钢锭模上焊补的应用

对损坏的钢锭模焊补是处长钢锭模寿命的措施之一。本文仅就ＣＯ２气体保护焊对球墨铸铁钢锭模焊补效果进行综合分析。     

CO2气体保护焊在高炉炉壳焊接上的应用

阐述ＧＥＣＮＣ０１数控系统结构原理、ＰＣ／２８６控制下软硬件结构、特点以及位置伺服、速度控制、零件加工程序的输入、解释等关键技术的实现；简单介绍系统的及经济效益，简要分析用通用计算机作为数控主机的先进性及存在的缺点。     

熔化极气体保护焊的应用前景

阐述了熔化极气体保护焊的应用，并将它与其它电弧焊的优缺点作了比较分析。     

CO2气体保护焊立焊工艺性能对比

某工程煤仓间落料斗主体纵向加筋板采用CO2气体保护焊立焊工艺。通过向上立焊、向下立焊两种工艺的对比试验及焊接工艺评定,得出向下立焊的可行性结论及应用条件,向下立焊焊接速度快、热输入量小、焊缝外观成型好,能够满足规范要求。     

X80钢气保焊焊缝金属的韧化

采用优化的WER70焊丝,在管线环焊缝常用焊接线能量条件下,对X80钢进行了气保焊试验.焊缝-20℃冲击功平均达到181 J,焊接接头具有较理想的组织,对接焊缝与焊丝熔敷金属的力学性能基本相当.     

高性能WNQ570桥梁钢厚板熔透角接试验研究

本文介绍新一代高性能WNQ570桥梁钢厚板熔透角接试验研究情况。研究结果表明,采用WER60气保护焊丝及富氩工艺焊接WNQ570钢,焊接接头具有优良的综合性能。采用的焊接工艺及焊接材料达到了大跨度桥梁钢接头性能指标。     

Influence of phosphorus in high strength steel on welding quality in laser welding

P-added high strength IF steel M250P1 is widely used in vehicle body and safety parts because of its good mechanical performance and forming properties.Experiments of high power laser welding of 4.8 mm thick P-added high strength IF steel M250P1 is performed by using a 12 kW CO₂ laser.In order to investigate the effects of phosphorus in high strength steel on the quality of welding,the Cupping and tensile tests,optical and SEM energy dispersive spectrometer analysis have been done on three welded joints.Some results have been obtained below.In the given welding parameters,the welded joints show good tensile and forming properties.However,it has been also found that the cracking is easy to occur in the fusion zone of welded joint during deformation.Some research works have been done.The results show that the fast cooling of fusional metal leads to the phosphorus microsegregation in the fusion zone because of relative low diffusion rate of phosphorus,which brings about the poor toughness of welded joints.     

铈对工程机械用700 MPa级高强钢焊接性能的影响

针对工业生产700 MPa级高强度调质态钢板,通过Gleeble3500热模拟机进行模拟焊接试验,利用光学显微镜、硬度仪、场发射扫描电镜等设备对比研究了稀土Ce对高强钢焊接热影响区（HAZ）显微组织、晶粒度和力学性能的影响。研究结果表明,焊接热输入为25 kJ·cm?1和50 kJ·cm?1时,无稀土钢焊接热影响区冲击功分别为84.8 J和24.5 J,Ce质量分数为0.0018%的钢焊接热影响区冲击功分别为110.0 J和112.0 J,因此钢中加入适量Ce能够有效改善钢板焊接韧性。对比分析两种实验钢焊接热影响区晶粒尺寸和显微组织可以看出,随着焊接热输入值增大,高强钢焊接热影响区显微组织均逐渐从马氏体、下贝氏体转变为上贝氏体和粒状贝氏体组织,且奥氏体晶粒尺寸明显增大。但相同焊接热输入下,含Ce钢焊接热影响区晶粒尺寸显著减小,组织更加细小,且脆性的上贝氏体组织减少,从而显著提高了700 MPa级高强钢的焊接性能。      

Joining of thick section steels using hybrid laser welding

Abstract

A recently completed project called Economical and Safe Laser Hybrid Welding of Structural Steel (HYBLAS) has developed the use of hybrid laser welding for thicker section steels up to 690 MPa yield strength. The full project involved several European organisations, was part funded by the European Research Fund for Coal and Steel (ERFCS) and was led by Corus RD&T. This paper presents an outline of those parts of the project which relate to those developments which resulted in being able to laser hybrid weld, in a single pass, up to 25 m plate thickness using 20 kW of laser power at speeds of ～1 m min^-1. Multipass and dual sided welding techniques have also been developed up to 30 mm plate thickness and fillet welds up to 20 mm steel thickness. The project examined the weldability of steels from 180-690 MPa and operational windows for defect free welding were defined. In addition various NDE methods were studied for their efficiency in regard to the defect types which can occur in laser hybrid welds. The fracture and mechanical properties of the joints were shown to be perfectly acceptable for all structural uses and an extensive fatigue testing programme demonstrated that the fatigue behaviour of the welded joints exceeded conventional welding expectations. Finally full scale industrial components were manufactured, inspected and tested to demonstrate that the anticipated fatigue benefits were obtained.     

Microstructure and properties of laser-arc hybrid welding of high-strength low-alloy steel

Laser-arc hybrid welding has the characteristics of optimal surface formation and greater penetration;it is extensively used in the welding of plates of medium thickness.However,for hybrid welding of lasers,the welding seam cooling rate is rapid;thus,the welding seam has a higher tendency to significantly harden,which has a negative impact on the weld quality of the high-strength low-alloy(HSLA)steel plates of medium thickness.In this study,laser-arc hybrid welding is performed on the BG890QL HSLA steel produced by Baoshan Iron&Steel Co.,Ltd.,and the quenching tendency of the welded structure is examined.The results demonstrate that the specific growth direction of the columnar crystal structure of the laser-arc hybrid welded joint is obvious.However,at the center and top of the welded seam,there are equiaxed crystals.The impact properties at room temperature and-40℃of the weld area are 58.0 J and 40.0 J,respectively,and those of the heat-affected zone(HAZ)are 147.0 J and 66.5 J,respectively.The impact performance can meet these requirements.Laser-arc hybrid welding of HSLA steel can yield strong and durable welds and the HAZ structure to meet the requirements of engineering applications.     

Numerical simulation of temperature field in laser-arc hybrid welding of wear-resistant steel

Using ABAQUS software and cylindrical ellipsoid and body heat sources with a peak-heat-fluxattenuation function,a finite element model of the temperature field in the laser-arc hybrid welding of 4.5-mm BW300TP wear-resistant steel is proposed.The proposed model considers convection,radiation,molten pool flow,and heat conduction effect on temperature.A comparison of the simulation and actual welding test results confirms the reliability of the model.This welding heat-process model can provide the cooling rate at any position in the heat affected zone (HAZ) and can be used as a reference for the analysis of material properties and for process optimization.     

Mechanism governing nitrogen absorption by steel weld metal during laser welding

The existence of monatomic nitrogen in the plasma just over the keyhole during CO₂ laser welding was confirmed by the monochromatic image of a specific spectrum line emitted by monatomic nitrogen. The smaller reaction area of the molten pool with monatomic nitrogen is considered to lead to less nitrogen absorption during CO₂ laser welding than that during arc welding. The effect of the penetration mode shows that the nitrogen absorption during CO₂ laser welding mainly occurs on the upper surface of the molten pool. The nitrogen content in a reduced-pressure nitrogen atmosphere during CO₂ laser welding is in good agreement with that obtained during yttrium aluminum garnet (YAG) laser welding within the range of low nitrogen (partial) pressures. This result supports the supposition that the different behaviors of nitrogen absorption between CO₂ laser welding and YAG laser welding can be reasonably attributed to the lesser amount of monatomic nitrogen during YAG laser welding.