MgO-CaO-SiO2焊接熔渣离子活度的热力学分析

针对焊接熔渣分子理论及离子理论存在的局限,基于冶金界近年来提出的熔渣共存理论,结合MgO-CaO-SiO2高温三元相图确定的结构单元,利用质量平衡原理建立了MgO-CaO-SiO2三元熔渣离子活度热力学计算模型,并借助于Matlab计算工具进行数值求解.计算结果表明,该模型可同时兼顾熔渣的分子理论和离子理论,离子活度随碱度的变化与碱度理论及直流焊接冶金电化学实验结果一致,在焊接化学冶金定量研究方面显示出良好的应用前景.     

耐磨损耐腐蚀粉末等离子弧堆焊技术的研究进展

粉末等离子弧堆焊技术作为表面强化技术手段之一，可显提高零部件表面耐磨损耐腐蚀性能。在介绍等离子弧粉末堆焊技术的原理及特点基础上，从等离子弧堆焊设备、堆焊用粉末及工艺三个方面阐述了国内外该技术的研究现状，并分析了该技术未来的发展趋势。     

油气长输管线对开三通综合量规的设计计算

主要是解决对开三通位置度及对开三通与夹板阀的连接问题，使对开三通制造达到国家标准。通过研究确定了对开三通综合量规的设计方案，即无基准活动式综合检验量规，并给出了综合量规设计的有关计算。     

Interfacial energy and match of cold pressure welded Ag/Ni and Al/Cu

The technology of cold pressure welding was adopted to achieve the bonding of Al/Cu(limited soluble and forming compounds),Ag/Ni(hardly mutual soluble),and the relative state of interface was tested by HREM.The results indicate that stable interface is always corresponding to the low interfacial energy value;the stable interface is not coherent but partly-coherent because of the twisting of grain boundary caused by pressure,meanwhile existing dislocation.Namely,the interfacial match and other states under the condition of cold pressure welding are different from the situation that under the condition of thermal action.Moreover,theoretical analyses and calculation on the base of thermodynamics,crystallogeny ,solid physics etc,were discussed.     

X70与CF62异种钢焊接工艺

通过对X70和CF62钢焊接接头低温冲击试验和组织的测定，结合“西气东输”工程站场内焊接施工的实际要求，研究了以上两种材料的异种钢焊接要点，该工艺已作为“西气东输”工程站场内的焊接工艺方案，并可为异种钢管的焊接提供可靠的技术参考。     

油气管道焊接施工过程中的磁偏吹

在石油、天然气长输管道焊接施工过程中，常常会遇到电弧偏吹现象。有些电弧偏吹产生原因难以确定，严重时甚至将焊丝、焊条吸到一边，造成连续或断续咬边、未焊透、熔合不良等缺陷，甚至无法施焊，严重影响焊接过程和焊缝成形。为此分析了油气管道焊接施工过程中磁偏吹的产生机理，并在长期的管道焊接施工经验的基础上总结了几种能够有效消除和减少磁偏吹的方法。     

Oblique Y-groove cracking test of the welding cold cracking susceptibility of domestic X-70 pipeline steel

“Gas Transmitting From West to East Project“ is significant.it should ensure the welding quality and safety of pipeline.The task is very arduous to guarantee the quality of the projcet in the condition of long line.complex weather and geolgy features.in this paper,the welding cold cracking susceptibility of domestic X-70 pipeline steel adopted by the project, which is one of the most interesting questions of welding quality about petrol pipeline,was studied by means of oblique Ygroove cracking test.The crack ration of surface and section was tested under the conditions of different welding materials and preheat temperature.The thickness of plate stell was 14.7mm and 10.3mm.The results reveal that X-70 pipeline steel has good crack resistance.The research has important value for the construction of large-scale pipeline engineering and the application of domestic X-70 pipeline steel.     

Characterization of the microstructure and hardness of the HAZ in a 800MPa grade RPC steel

The microstructure and hardness of the HAZ in a 800MPa grade ultra-low-carbon microalloyed steel were studied.The results indicate that the heat affected zone(HAZ) of the RPC (Relaxation- Precipitation- Controlling) steel possesses a continuous gradient structure, and can be classified into three zones, i. e. CGHAZ (coarse-grain HAZ) , FGHAZ (fine-grain HAZ) and ICHAZ(intercritical temperature HAZ). The microstructures in the HAZ are all composed of bainite-like structure.The microstructure in the CGHAZ mainly consists of lath-like bainite and granular bainite . The influences of heat input and t8/5 on the hardness in the HAZ of RPC steel are notable. With the increase of heat input and t8/5, the softening tendency of HAZ becomes obvious. The hardening phenomenon that normally occurs in the CGHAZ does not take place with this steel in the range of experimental conditions. The softening in the ICHAZ is bound to occur. Hence appropriate welding technologies need to be selected.     

Effect of Mn and MnS on corrosion properties of domestic pipeline steels and welds

Base metals of domestic pipeline steels were used to study the effect of Mn on corrosion properties of SSCC( Sulfide Stress Corrosion Cracking), and welds were carried out to study the effect of MnS on corrosion properties of HIC ( Hydrogen Induced Cracking) both in solutions with wet hydrogen sulfide ( H2 S ). They were respectively conducted by referring to the standards of SSCC and HIC. Testing results revealed that with the increase of content Mn, the resistance of SSCC will be decreased, from the point of metallurgic view, and it is Mn element not C element to lead to the testing results of SSCC. Meanwhile, even under the condition without inclusions MnS, HIC in welds still occurred. That is to say, MnS is not necessary for HIC, the presence of local banded structures in which Mn and P are inclined to aggregate cause to the phenomena of HIC.     

高强度级别管线钢的焊接

我国石油天然气长输管线正面临飞速发展的历史时期,使用高强度级别管线钢,已成为国际上管线建设的重要趋势.重点介绍了高强度级别管线钢的发展情况、显微组织特点;分析了管线钢的焊接性.对于德国、加拿大等国际上X80管线钢的工程实例进行了简要的介绍;同时,对我国冶金、制管行业近年来研制开发X80板材、管材的情况进行了综述;尤其对我国管道行业X80钢焊接研究及实际工程应用的准备工作进行了概述.从而指出我国的冶金、制管、焊材、焊接设备、管道研究、施工、管理及技术部门都应抓住机遇,为管道事业作出贡献.