在螺旋3PEfangfugangguandeshiyongheshengchanjinchengzhong，renleifaminglehenduodeyouxiudehanjieheshengchandefangfa，dadacujinlezheyixingyedewenbukuaisudefazhan
，tongshiyeshidecixingyezaifazhanzhongdedaoyouhua。qizhongmaihuzidonghanshizai1940nianfamingdeyizhongxindehanjiefangfa

，taheqianmiandeshougonghanxiangtongdedifangshitahaishicaiyongzhabaohu，danshizhegezhabushihantiaodeyaopi，shizhuanmenronglianchulaidehanyao。gaichenghansiyihou，yongsonghansidezhuangzhihehansipan，lianxudisonggeihansi，zhezhonghanjiefangfashilianxusongjindehansi，zaikeronghuadekelizhuangdehanjifugaixiayinrandianhu
，shihansi、母材和焊劑的一部分熔化和蒸發構成一個空腔，電弧是在空腔裏麵穩定燃燒,所以把它稱之為埋弧自動焊。電弧是埋在空腔裏邊的。這個焊藥係統由一個漏鬥裝的焊藥通過一個管道輸送到要焊接的前麵.二個不同是不采用焊條，采用焊絲，因為焊絲可以連續送給；焊(han)條(tiao)，我(wo)們(men)燒(shao)完(wan)一(yi)根(gen)焊(han)條(tiao)總(zong)得(de)有(you)一(yi)個(ge)焊(han)條(tiao)頭(tou)就(jiu)給(gei)扔(reng)了(le)，而(er)且(qie)操(cao)作(zuo)得(de)停(ting)下(xia)來(lai)，換(huan)焊(han)條(tiao)然(ran)後(hou)再(zai)焊(han)。而(er)此(ci)種(zhong)焊(han)接(jie)方(fang)法(fa)與(yu)其(qi)他(ta)方(fang)法(fa)相(xiang)比(bi)是(shi)有(you)很(hen)大(da)的(de)優(you)點(dian)的(de).埋弧焊3PE防腐螺旋鋼管的這種焊接這種方法
，個優點是完全實現了自動化；二個優點,它是在埋弧底下進行焊接，所以它的熱交換和保護性能比較強,焊接出來的質量比較高；三個優點，由於埋弧自動焊中電弧埋在焊藥底下，所以它可以采用大電流,焊接效率比較高。

    聚乙烯結構3PE防腐鋼管防腐層保溫性能佳，3PE防fang腐fu鋼gang管guan保bao溫wen性xing能neng好hao，熱re損sun失shi僅jin僅jin為wei傳chuan統tong管guan材cai的de百bai分fen之zhi二er十shi五wu
，長chang期qi運yun行xing還hai是shi可ke以yi節jie約yue比bi較jiao大da的de資zi源yuan，明ming顯xian的de降jiang低di能neng源yuan成cheng本ben，並bing且qie還hai是shi具ju有you比bi較jiao強qiang的de防fang水shui和he耐nai腐fu蝕shi能neng力li，並bing且qie也ye不bu需xu要yao附fu設she管guan溝gou，直zhi接jie就jiu可ke以yi買mai入ru地di下xia或huo者zhe水shui中zhong
，在zai施shi工gong上shang也ye是shi簡jian便bian迅xun速su，綜zong合he的de造zao價jia也ye比bi較jiao低di，在zai低di溫wen條tiao件jian下xia也ye是shi具ju有you良liang好hao的de耐nai腐fu蝕shi和he耐nai衝chong擊ji性xing，並bing且qie在zai一yi定ding的de環huan境jing中zhong還hai可ke以yi直zhi接jie的de埋mai入ru凍dong土tu。聚ju乙yi烯xi三san層ceng結jie構gou防fang護hu層ceng又you稱cheng3PE防腐鋼管，是近幾年從國外引進的先進的防腐技術。它的全稱為熔結環氧/擠塑聚乙烯結構防護層，結構由以下三層組成：底層為熔結環氧(≥80μm);中間層為膠粘劑(170—250μm);麵層為擠塑聚乙烯(約2mm)。防護層總厚度約1.8-3.7mm。在三層結構中，熔結環氧粉末塗層的主要作用是：形成連續的塗膜
，與鋼管表麵直接粘結
，具有很好的耐化學腐蝕性和抗陰剝離性能
；與yu中zhong間jian層ceng膠jiao粘zhan劑ji的de活huo性xing基ji團tuan反fan應ying形xing成cheng化hua學xue粘zhan結jie，保bao證zheng整zheng體ti防fang腐fu層ceng在zai較jiao高gao溫wen度du下xia具ju有you良liang好hao的de粘zhan結jie性xing。中zhong間jian層ceng通tong常chang為wei共gong聚ju物wu粘zhan結jie劑ji，其qi主zhu要yao成cheng分fen是shi聚ju烯xi烴ting，目mu前qian廣guang泛fan采cai用yong的de是shi乙yi烯xi基ji共gong聚ju物wu膠jiao粘zhan劑ji。共gong聚ju物wu膠jiao粘zhan劑ji的de性xing部bu分fen官guan能neng團tuan與yu熔rong結jie環huan氧yang粉fen末mo塗tu層ceng的de環huan氧yang基ji團tuan可ke以yi反fan應ying生sheng成cheng氫qing鍵jian或huo化hua學xue鍵jian

，使shi中zhong間jian層ceng與yu底di層ceng形xing成cheng良liang好hao的de粘zhan結jie；erfeixingdeyixibufenyumiancengjuyixijuyouhenhaodeqinhezuoyong
，suoyizhongjiancengyumiancengyejuyouhenhaodezhanjiexingneng。juyiximiancengdezhuyaozuoyongshiqijixiebaohuyufangfuzuoyong，yuchuantongdeercengjiegoujuyixifangfucengjuyoutongyangdezuoyong。 

    目前，直縫埋弧焊管應用已擴展到眾多領域，除石油天然氣長輸管道外，還向海洋平台、海hai上shang浮fu吊diao等deng海hai洋yang結jie構gou方fang麵mian發fa展zhan。埋mai弧hu焊han管guan作zuo為wei海hai洋yang結jie構gou用yong管guan具ju有you明ming顯xian的de優you勢shi，如ru壁bi厚hou均jun勻yun，工gong藝yi簡jian單dan，性xing能neng受shou製zhi管guan工gong藝yi影ying響xiang較jiao小xiao，易yi於yu實shi現xian高gao強qiang度du

、gaorenxingdeyaoqiu，qieqiguigetiaozhenglinghuo，kemanzubutongguanjingdeyaoqiu。danshi，youyuhaiyangjiegouyongguandefuyihuanjingyulululiutishusongguanyousuobutong
，haiyangjiegouyongguanfuyizaibolang、海潮
、fengbaojihanlengliubingdengyanjundehaiyanggongzuohuanjingzhong
，yiner
，duihaiyangjiegouyongguanchuleyaoqiujuyouyibanguandaoxingnengwai，haiduiqiqiangrenxinghehanfengzhiliangtichulegenggaodeyaoqiu。gangguandezhuyaocaizhiweiD36鋼、S355鋼及具有Z向性能的結構鋼板
，厚度一般在20～50 mm之間，由於板材厚度較大，且碳含量及碳當量均較大，可焊性較差，淬硬傾向大，使焊接接頭的熔合性能降低

，且易產生冷裂紋。

     厚壁直縫埋弧焊管焊縫存在的橫向裂紋分別采用厚度為20～50mm的D36，D36-Z35和S355結構鋼板
，通過JCOE成型方式生產海洋經驗交流·54·HAN GUAN焊管平台用直縫埋弧焊管，直徑為508～1372mm。焊縫采用X形坡口
，內焊為三絲埋弧焊，外焊為多層多道三絲埋弧焊。焊接完成24h或48hhouduihanfengjinxingchaoshengbojiance，hengxiangsaozhashifaxianzaihanfengbihouzhongjianweizhiyoulinzhuanghuibochuxian

，jinyibujiancefaxianyoushizhengtiaohanfengduanxucunzaileisixinhao，shenduzaihanfengzhongjianweizhi。weilezhaqingquexiandexingzhi
，duimouxiefanshexinhaogaodedifangjinxingX射she線xian拍pai片pian
，未wei發fa現xian缺que陷xian。經jing碳tan弧hu氣qi刨pao後hou再zai次ci進jin行xing磁ci粉fen檢jian測ce
，證zheng實shi該gai缺que陷xian為wei橫heng向xiang裂lie紋wen。裂lie紋wen大da部bu分fen橫heng穿chuan焊han縫feng，但dan未wei擴kuo展zhan到dao母mu材cai中zhong，裂lie紋wen深shen度du在zai焊han縫feng壁bi厚hou的de中zhong間jian位wei置zhi，為wei外wai焊han的de一yi層ceng，與yu超chao聲sheng波bo檢jian測ce的de深shen度du基ji本ben吻wen合he。