有(you)的(de)設計人員(yuan)咨詢浙江(jiang)至德鋼業(ye)有(you)限公司工程師工業(ye)管道(dao)(dao)與(yu)輸氣管道(dao)(dao)的(de)壁(bi)(bi)厚計算是否可以統一(yi)或者(zhe)互(hu)相替代使(shi)用(yong)?因兩者(zhe)的(de)壁(bi)(bi)厚計算具有(you)以下區別,所以肯定是不能混(hun)用(yong)的(de)。



一、工業管道與輸氣管道直管壁厚計算公式(shi)比較(jiao)


 1. 壁厚計算理論基礎比較(jiao)


   承受內(nei)壓(ya)的(de)直管屬于旋轉殼體的(de)一種,旋轉殼體應(ying)(ying)(ying)(ying)(ying)力(li)(li)(li)分析(xi)理(li)論有兩類:一類是(shi)忽略彎矩的(de)無力(li)(li)(li)矩理(li)論一-薄膜(mo)理(li)論,導出的(de)是(shi)壁(bi)厚計(ji)算(suan)的(de)薄膜(mo)應(ying)(ying)(ying)(ying)(ying)力(li)(li)(li)公式,該公式計(ji)算(suan)的(de)是(shi)沿(yan)壁(bi)厚均勻分布的(de)兩向(xiang)(xiang)應(ying)(ying)(ying)(ying)(ying)力(li)(li)(li),即(ji)軸(zhou)向(xiang)(xiang)應(ying)(ying)(ying)(ying)(ying)力(li)(li)(li)和(he)周(zhou)向(xiang)(xiang)應(ying)(ying)(ying)(ying)(ying)力(li)(li)(li),忽略了徑向(xiang)(xiang)應(ying)(ying)(ying)(ying)(ying)力(li)(li)(li)。另一類是(shi)彈性(xing)力(li)(li)(li)學應(ying)(ying)(ying)(ying)(ying)力(li)(li)(li)分析(xi)理(li)論一一拉(la)美公式,共三個(ge)方向(xiang)(xiang)的(de)應(ying)(ying)(ying)(ying)(ying)力(li)(li)(li),周(zhou)向(xiang)(xiang)應(ying)(ying)(ying)(ying)(ying)力(li)(li)(li)和(he)徑向(xiang)(xiang)應(ying)(ying)(ying)(ying)(ying)力(li)(li)(li)沿(yan)壁(bi)厚非線性(xing)分布,軸(zhou)向(xiang)(xiang)應(ying)(ying)(ying)(ying)(ying)力(li)(li)(li)沿(yan)壁(bi)厚均勻分布。


   GB 50251《輸氣管(guan)道(dao)(dao)(dao)工(gong)(gong)程設計(ji)規范》采用(yong)ASME B31.8《輸氣和(he)配氣管(guan)道(dao)(dao)(dao)系統》的(de)壁(bi)厚計(ji)算公(gong)(gong)(gong)式(shi)(shi),公(gong)(gong)(gong)式(shi)(shi)源于無力(li)(li)矩理論的(de)薄(bo)膜理論應力(li)(li)公(gong)(gong)(gong)式(shi)(shi)。GB/T 20801、GB 50316、SH/T 3059等(deng)標準采用(yong)ASME B31.3《工(gong)(gong)藝(yi)管(guan)道(dao)(dao)(dao)》的(de)壁(bi)厚計(ji)算公(gong)(gong)(gong)式(shi)(shi),公(gong)(gong)(gong)式(shi)(shi)是拉美公(gong)(gong)(gong)式(shi)(shi)的(de)經驗近似式(shi)(shi)。輸氣管(guan)道(dao)(dao)(dao)壁(bi)厚計(ji)算公(gong)(gong)(gong)式(shi)(shi)的(de)理論基(ji)礎采用(yong)無力(li)(li)矩理論-薄(bo)膜理論,而工(gong)(gong)業管(guan)道(dao)(dao)(dao)采用(yong)彈性力(li)(li)學應力(li)(li)分析理論-拉美公(gong)(gong)(gong)式(shi)(shi)。


 2. 安全系數取值方式的比較


   輸氣管(guan)道(dao)(dao)由于需穿(chuan)越城(cheng)市、村鎮等,根據管(guan)道(dao)(dao)通(tong)過區(qu)域(yu)的(de)(de)(de)不(bu)同(tong)條件,采用改(gai)變管(guan)道(dao)(dao)應力(li)水平(即(ji)改(gai)變管(guan)道(dao)(dao)壁(bi)厚(hou))以強(qiang)(qiang)(qiang)度(du)(du)確保管(guan)道(dao)(dao)自(zi)(zi)身的(de)(de)(de)安(an)全(quan),為管(guan)道(dao)(dao)周圍(wei)環境(jing)提供(gong)安(an)全(quan)保障(采用不(bu)同(tong)的(de)(de)(de)強(qiang)(qiang)(qiang)度(du)(du)設計系數(shu)F)的(de)(de)(de)理念,同(tong)時也體(ti)現了管(guan)道(dao)(dao)的(de)(de)(de)經(jing)濟成本(ben)的(de)(de)(de)合(he)理性。GB50251中(zhong)規(gui)定(ding)(ding)的(de)(de)(de)強(qiang)(qiang)(qiang)度(du)(du)設計系數(shu)F值,一級(ji)(ji)地區(qu)為0.8,四級(ji)(ji)地區(qu)為0.4。強(qiang)(qiang)(qiang)度(du)(du)設計系數(shu)F值的(de)(de)(de)規(gui)定(ding)(ding)與取值源(yuan)自(zi)(zi)ASME B31.8《輸氣和(he)配氣管(guan)道(dao)(dao)系統》。


   工業(ye)管(guan)道(dao)壁厚計算中(zhong),設(she)(she)計溫度下的(de)(de)(de)材(cai)料(liao)許(xu)(xu)用(yong)(yong)應力(li)(li)由材(cai)料(liao)的(de)(de)(de)力(li)(li)學性(xing)能(neng)除(chu)以相應的(de)(de)(de)安(an)(an)全(quan)(quan)(quan)系(xi)(xi)數(shu)而(er)得,GB/T 20801、GB 50316、SH/T 3059規定(ding)的(de)(de)(de)材(cai)料(liao)安(an)(an)全(quan)(quan)(quan)系(xi)(xi)數(shu)與(yu)GB 150中(zhong)材(cai)料(liao)安(an)(an)全(quan)(quan)(quan)系(xi)(xi)數(shu)的(de)(de)(de)要求相同。由于工業(ye)管(guan)道(dao)處(chu)于有限(xian)(xian)范圍(wei)的(de)(de)(de)工廠環(huan)境(jing)中(zhong),材(cai)料(liao)的(de)(de)(de)安(an)(an)全(quan)(quan)(quan)系(xi)(xi)數(shu)根據材(cai)料(liao)的(de)(de)(de)類型和力(li)(li)學性(xing)能(neng)(強(qiang)度極限(xian)(xian)、屈服極限(xian)(xian)、持(chi)久(jiu)強(qiang)度、蠕變極限(xian)(xian))的(de)(de)(de)不同而(er)取值(zhi),按照規范規定(ding)選取許(xu)(xu)用(yong)(yong)應力(li)(li)值(zhi)。許(xu)(xu)用(yong)(yong)應力(li)(li)值(zhi)的(de)(de)(de)大小(xiao)與(yu)工業(ye)管(guan)道(dao)所處(chu)的(de)(de)(de)環(huan)境(jing)條件完全(quan)(quan)(quan)無關(guan),在GB/T20801、GB 50316、SH/T 3059等中(zhong)規定(ding)使用(yong)(yong)應力(li)(li)表(biao)中(zhong)的(de)(de)(de)值(zhi),既體現了許(xu)(xu)用(yong)(yong)應力(li)(li)所表(biao)達的(de)(de)(de)安(an)(an)全(quan)(quan)(quan)強(qiang)度,又(you)體現了工程(cheng)設(she)(she)計的(de)(de)(de)經濟合理性(xing)。


   輸氣(qi)管道和工業管道壁厚計算公式(shi)中(zhong)安全系數的區別,在安全理念(nian)和規范內容上(shang)存(cun)在差異,在設計上(shang)是無法統一的。


 3. 鋼管壁(bi)厚附加裕量的比較


   輸(shu)氣管(guan)道在用公(gong)式得出計算壁(bi)厚(hou)之(zhi)后,圓整到鋼(gang)管(guan)標準規(gui)定的壁(bi)厚(hou),一般(ban)沒有(you)考慮(lv)材料厚(hou)度(du)偏差和腐蝕裕量。但(dan)是ASME B31.8規(gui)定采(cai)用該(gai)規(gui)范(fan)所列鋼(gang)管(guan),已經考慮(lv)了鋼(gang)管(guan)的壁(bi)厚(hou)負偏差,并(bing)且加了裕量,例如(ru),如(ru)采(cai)用API5L,則(ze)不必(bi)再另加厚(hou)度(du)負偏差了。


  工業管道的壁厚計算公式中則明確規定了應該考慮厚度減薄附加量C1和腐蝕磨蝕附加量C2



二、鋼管材料選用的(de)比較


  由于輸(shu)氣管(guan)道(dao)距離長,鋼(gang)(gang)(gang)管(guan)用(yong)量大,天然(ran)氣輸(shu)送量大,輸(shu)氣管(guan)道(dao)朝(chao)著高壓力、大直(zhi)徑方向發展,鋼(gang)(gang)(gang)管(guan)材料也朝(chao)著高強(qiang)度(du)、微合金的(de)(de)(de)方向發展。與輸(shu)氣管(guan)道(dao)工程相配套的(de)(de)(de)鋼(gang)(gang)(gang)管(guan)也有了自成體(ti)系(xi)(xi)的(de)(de)(de)鋼(gang)(gang)(gang)管(guan)標(biao)(biao)準(zhun),在(zai)國際(ji)上得到廣(guang)泛(fan)應(ying)用(yong)的(de)(de)(de)鋼(gang)(gang)(gang)管(guan)標(biao)(biao)準(zhun)是(shi)美國標(biao)(biao)準(zhun)API5L。該標(biao)(biao)準(zhun)的(de)(de)(de)最(zui)高鋼(gang)(gang)(gang)級為(wei)L830M(PSL2),規(gui)定(ding)的(de)(de)(de)屈服強(qiang)度(du)最(zui)小(xiao)值為(wei)830 MPa。ISO 3183《石(shi)油天然(ran)氣工業(ye)管(guan)線輸(shu)送系(xi)(xi)統(tong)用(yong)鋼(gang)(gang)(gang)管(guan)》是(shi)在(zai)API5L《管(guan)線鋼(gang)(gang)(gang)管(guan)規(gui)范》基礎(chu)上編制的(de)(de)(de)。GB/T 9711《石(shi)油天然(ran)氣工業(ye) 管(guan)線輸(shu)送系(xi)(xi)統(tong)用(yong)鋼(gang)(gang)(gang)管(guan)》是(shi)在(zai)ISO 3183標(biao)(biao)準(zhun)基礎(chu)上修改編制的(de)(de)(de),該標(biao)(biao)準(zhun)得到了廣(guang)泛(fan)應(ying)用(yong)。與工業(ye)管(guan)道(dao)用(yong)鋼(gang)(gang)(gang)管(guan)在(zai)技術(shu)上有重大區別。GB 50349《氣田集輸(shu)設計規(gui)范》規(gui)定(ding)氣田集輸(shu)管(guan)道(dao)用(yong)鋼(gang)(gang)(gang)管(guan)也是(shi)選(xuan)用(yong)GB/T 9711。


  工業管(guan)道(dao)(dao)所屬裝置的(de)(de)(de)管(guan)道(dao)(dao)流體多樣(yang)化、設計(ji)參數各不相同,工業管(guan)道(dao)(dao)的(de)(de)(de)器(qi)材選用(yong)(yong)(yong)(yong)(yong)尚無(wu)(wu)自(zi)成(cheng)體系的(de)(de)(de)統一標準,均是(shi)使用(yong)(yong)(yong)(yong)(yong)相應的(de)(de)(de)鋼(gang)材和鋼(gang)管(guan)標準,例(li)如國標鋼(gang)管(guan)常(chang)用(yong)(yong)(yong)(yong)(yong)標準:GB/T13793《直縫(feng)電焊鋼(gang)管(guan)》,GB/T9948《石油(you)裂化用(yong)(yong)(yong)(yong)(yong)無(wu)(wu)縫(feng)鋼(gang)管(guan)》,GB/T 6479《高(gao)壓(ya)化肥(fei)設備用(yong)(yong)(yong)(yong)(yong)無(wu)(wu)縫(feng)鋼(gang)管(guan)》,GB/T8163《輸(shu)送流體用(yong)(yong)(yong)(yong)(yong)無(wu)(wu)縫(feng)鋼(gang)管(guan)》,GB/T3087《低中(zhong)壓(ya)鍋爐(lu)用(yong)(yong)(yong)(yong)(yong)無(wu)(wu)縫(feng)鋼(gang)管(guan)》,GB/T5310《高(gao)壓(ya)鍋爐(lu)用(yong)(yong)(yong)(yong)(yong)無(wu)(wu)縫(feng)鋼(gang)管(guan)》等(deng)數十(shi)個,工業管(guan)道(dao)(dao)器(qi)材選用(yong)(yong)(yong)(yong)(yong)具體規定與輸(shu)氣(qi)管(guan)道(dao)(dao)的(de)(de)(de)材料(liao)要(yao)求是(shi)大不一樣(yang)的(de)(de)(de),輸(shu)氣(qi)管(guan)道(dao)(dao)與工業管(guan)道(dao)(dao)在材料(liao)選用(yong)(yong)(yong)(yong)(yong)及材料(liao)標準上均有很大區別(bie)。



三、管道沖擊試驗的(de)比較


  輸氣(qi)管(guan)(guan)道(包括輸氣(qi)站)一般都(dou)在野(ye)外(wai),受自然環(huan)(huan)境(低溫(wen)(wen))的影響(xiang)比(bi)較大,輸氣(qi)管(guan)(guan)道用鋼管(guan)(guan)對低溫(wen)(wen)沖(chong)擊韌性(xing)的要(yao)求較高(gao),以防止鋼管(guan)(guan)脆(cui)性(xing)斷(duan)裂(lie)擴展和(he)控制延(yan)性(xing)斷(duan)裂(lie)擴展。我國對干線和(he)站場用鋼管(guan)(guan)提出了在API5L的基礎上(shang)對鋼管(guan)(guan)和(he)焊縫進(jin)行夏比(bi)沖(chong)擊試驗的要(yao)求,規定其試驗溫(wen)(wen)度應低于管(guan)(guan)道通過當地的最低環(huan)(huan)境溫(wen)(wen)度,一般取(qu)-10℃,-20℃、-30℃,夏比(bi)沖(chong)擊韌性(xing)合(he)格值(zhi)根據(ju)不同鋼級和(he)管(guan)(guan)徑分別(bie)為27J、40J、54J、80J(3個試樣最小平(ping)均值(zhi))。


  工業(ye)管道對管道設(she)計溫(wen)度(du)≤-20℃而高于鋼(gang)材使(shi)用溫(wen)度(du)下限(xian)的碳素(su)鋼(gang)、低合金鋼(gang)、中(zhong)合金鋼(gang)和高合金鐵素(su)體鋼(gang),要求進行夏比低溫(wen)沖(chong)擊(ji)試驗,試驗沖(chong)擊(ji)功合格值根據不同(tong)的鋼(gang)材分別(bie)為18J、20J、27J、31J(3個(ge)試樣(yang)平均值),GB/T 20801、GB/T 50316、SH/T 3059等標(biao)注中(zhong)均有明(ming)確(que)規定(ding)。


  輸氣管道與(yu)工業管道設計(ji)規范對鋼管提出(chu)了夏比低溫(wen)沖擊(ji)試驗的(de)(de)要求,在夏比低溫(wen)沖擊(ji)試驗的(de)(de)試驗溫(wen)度與(yu)合格(ge)值上差異(yi)較大。






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