本文选取电站锅炉小口径管中12Cr1MoVG、SA-213 T91、SA-213 TP347H进行了手工钨极氩弧焊常规焊接参数与非常规焊接参数的对比试验.试验结果显示,采用非常规参数的对接焊接接头在硬度、常温冲击韧性、断口检查、金相检验中出现了多种问题,而且由于RT无损检测的局限性,对小口径管对接焊缝中的未熔合、微裂纹等缺陷很难检出,造成电厂运行中的隐患.因此,小口径管手工钨极氩弧焊的焊接参数应在保证大批量焊接质量的前提下合理选取.

G115钢是研发630℃高效超超临界锅炉关键部件的重要候选材料之一,通过斜Y形坡口焊接裂纹试验、焊接热影响区最高硬度试验,对G115钢焊接冷裂纹敏感性进行研究.结果表明:G115钢冷裂倾向较大,但是预热到150℃时,可有效降低焊接冷裂纹出现的概率.

本文对电站锅炉受热面部件中奥氏体与铁素体异种钢焊接接头的失效案例进行了总结分析,认为设计结构因素、焊接质量问题、运行环境是促进异种钢失效的主要外因,并从全过程质量控制的角度提出了降低失效风险的应对方法.

燃煤电站锅炉吊挂管为小批量焊接结构,涉及材质种类多、结构复杂.焊接特点为:存在焊接变形,焊接材料为合金耐热钢和不锈钢,异种钢焊接.吊挂管原焊接方法为焊条电弧焊,焊接效率低、质量稳定性差、工人劳动强度高.吊挂管自动化焊接生产线实现了电站锅炉产品中角板两侧对称的吊挂管自动化焊接,包括上料、点焊、焊接、下料、转运等全流程.经过试验,该生产线焊接的焊缝成型均匀一致,满足标准要求,焊接合格率超过99％,目前该设备已经在1000 MW超超临界锅炉、600 MW超超临界锅炉等国内外诸多燃煤电站锅炉项目中大范围应用.

采用拉拔式弯曲方法制备16Mo3材料弯管试样,经过695℃恒温0.5 h和1.0 h退火热处理后进行维氏硬度测试和微观组织分析.试验结果表明:经过695℃/1.0 h热处理后,弯管试样不同位置处的硬度由200 HV10以上降至约150 HV10,且原来畸变的晶粒也转变为等轴晶状.

采用热丝TIG的方法制备VM12材料焊接接头,对焊态、焊后退火态以及时效热处理态接头的力学性能和金相组织展开研究.焊后观察到焊缝为马氏体+残余奥氏体组织,且焊缝硬度很高,经退火热处理后焊缝转变为回火马氏体,硬度降至300HV10左右;接头经600℃和650℃时效热处理后,微观组织变化很小,材料高温稳定性较好.

采用热丝TIG焊方法对Inconel740H镍基合金与Haynes282镍基合金异种材料进行焊接,并对采用Ineonel Filler Metal 740H镍基合金焊丝和Haynes 282 Wire镍基合金焊丝两种不同焊接填充金属分别经过两步时效强化热处理(1 010℃/2 h/空冷+788C/8 h/空冷)和一步时效强化热处理(800℃/4 h/空冷)后的接头拉伸性能、弯曲性能、硬度和微观组织进行对比分析.试验结果表明,焊接接头的抗拉强度均大于1 035 MPa,弯曲试验均合格,焊接接头的硬度均大于314 HV.焊接接头金相组织检验合格,焊缝组织均为奥氏体,焊缝内的晶界处均存在细小的碳化物析出,未发现有害相的析出.

为研究SA-213T91管子与不锈钢承载附件是否可采用AWS E9015-B9焊材,本文采用手工氩弧焊+焊条电弧焊的方法对SA-387Gr91 +06Cr25Ni20异种钢进行焊接.对焊接接头进行RT检测、室温力学性能检测和金相显微组织分析.从焊接工艺评定和模拟件焊接试验的角度认为,SA-213T91小口径管子与承受载荷的奥氏体不锈钢附件之间焊接,可以选用合金钢焊材AWS E9015-B9.

本文介绍了窄间隙焊接工艺在电站锅炉小口径管制造中的应用,阐述了窄间隙坡口的加工要求、窄间隙热丝TIG焊的参数设定、窄间隙手工氩弧焊的操作要点及窄间隙坡口焊接接头在力学性能方面的优势等.

为研究VM12耐热钢与SA-213TP347H奥氏体不锈钢焊接接头的性能,采用钨极惰性气体保护焊的方式连接两种材料,利用光学显微镜观察接头微观组织,并进行一系列力学性能测试,研究了在试验工艺参数下异种钢接头的显微组织特征及各项力学性能指标.试验结果表明,使用镍基合金焊材连接马氏体和奥氏体材料,可以得到质量良好的奥氏体+铁素体组织焊缝,异种钢焊接接头具有良好的室温抗拉性能、弯曲性能及冲击韧性,但VM12侧热影响区与焊缝间硬度差值较大;经过长期服役后可能会降低焊接接头整体的延展性,容易在此区域产生缺陷.

本文介绍了700℃先进超超临界燃煤电站研发中的一种候选材料Haynes282合金,通过试验确定了其小口径无缝管对接接头手工钨极氩弧焊、热丝TIG焊的焊接工艺要点及焊接接头常温力学性能.

为了研究Sanicro 25的焊接工艺性和接头力学性能,采用热丝TIG焊对新型奥氏体不锈钢管Sanicro 25进行焊接,并采用喷水工艺控制层间温度,按JB/T 4730标准对焊接接头进行RT检测,进行拉伸、弯曲、冲击试验和金相组织分析.试验结果表明:Sanicro 25焊接性能良好,接头性能满足材料要求,焊接接头在700℃高温持久试验外推1×105强度能满足材料在650℃～700℃工况条件下长期使用运行.

This article introduce the characteristic of water-cooled hot-wire GTAW procedure,and how to decide the reasonable welding parameters base on the test which simulate the producing process,then make the conclusions after analyzing the test results.

Using panel data of 30 Chinese provinces,municipalities and autonomous regions(excluding Hongkong, Macau and Tibet)from 2001 to 2011,we found that house price increases significantly depressed household demands for life insurance.With other parameters being unchanged,a 1%increase in average residential house price reduced per capita life insurance premium income by 0.529%.And the impacts on health insurance demands were the most negative.When other parameters remained stable,1%increase in average residential house price reduced per capita health insurance premium income by 1.673%.In contract,house price fluctuation didn' t have a conspicuous effect on group life insurance demands.

The mechanical properties,serial impact toughness of the welded joint aged at 700℃ for long time of HR3C were tested in this paper,optical microscopes were used to observe and analyze the microstructure.The tests show that the welded joints aged at 700 ℃ for long time of HR3C have good tensile property,but the compounds have precipitated from the inside and borderline of grain,the bend samples have ruptured absolutely.

The effects of solution treatment on welded joint of new type austenitic steel were investigated in this article,optical microscopes were used to observe and analyze the microstructure,tensile and bend testing machines were used to test mechanical properties of welded joint.Results showed that the hardness and the evaluated temperature tensile property of the welded joint is decrease,but the room temperature tensile property is higher and the corrosion resistance property is improved by solution treatment.

The paper introduced some new materials with good high temperature creep and oxidation resistance, which were applied in ultra supercritical boiler. The chemical composition and mechanical properties of the new materials were summarized. The basic requirements for welded joints and welding procedure were introduced.

采用焊接热模拟的方法,模拟HAZ粗晶区组织,并在不同温度下对试样进行焊后热处理,通过冲击试验及断口分析,确定P122钢合理的焊后热处理温度为750℃,其冲击吸收功值与母材的相近,韧性较好。

This article introduces how to decide preheat temperature and heat treatment standard of SA-335P122 by slit type cracking test and synthetic heat-affected zone test,and successfully complete the welding of main steam pipe of φ559 mm×102 mm SA-335P122 of 1 000 MW Yuhuan project by analyzing welding properties of SA-335P122 and selecting welding material reasonably.

0 前言 哈尔滨锅炉厂有限责任公司的钢结构扩散厂家——二十冶钢结构制造总厂在16Mn大板粱对接及角接埋弧自动焊焊缝上发现了很多裂纹，裂纹沿焊缝中心呈纵向分布，开裂长度从十几毫米到几十毫米。经多方面的调查和分析，首先确认了焊接工艺是正确的。对产生裂纹的焊缝进行化学分析，发现熔敷金属含磷量偏高，接着对母材、焊丝、焊剂进行化学分析，发现母材、焊丝化学成份符合标准要求，而有一批号的焊剂含磷量高达0.418%。分析认为焊剂中过高的含磷量导致焊缝产生了裂纹。