1. 浙江至德(de)鋼(gang)業有(you)限公司發現有(you)的(de)配管(guan)(guan)(guan)(guan)(guan)設(she)計(ji)人員，經常混用英(ying)制(zhi)管(guan)(guan)(guan)(guan)(guan)和(he)公制(zhi)管(guan)(guan)(guan)(guan)(guan)（注(zhu)意(yi)區(qu)分(fen)管(guan)(guan)(guan)(guan)(guan)子(zi)(zi)(zi)公稱直徑(jing)(jing)是(shi)用英(ying)寸(cun)表(biao)示(shi)還是(shi)用毫米(mi)表(biao)示(shi)的(de)不同）。石(shi)油化工行業管(guan)(guan)(guan)(guan)(guan)子(zi)(zi)(zi)有(you)公制(zhi)和(he)英(ying)制(zhi)兩(liang)(liang)種。公制(zhi)鋼(gang)管(guan)(guan)(guan)(guan)(guan)是(shi)按ISO4200《焊接(jie)(jie)和(he)無(wu)縫(feng)(feng)平端鋼(gang)管(guan)(guan)(guan)(guan)(guan)管(guan)(guan)(guan)(guan)(guan)的(de)尺寸(cun)和(he)單(dan)位(wei)長(chang)度重量(liang)一(yi)覽表(biao)》標(biao)準(zhun)(zhun)制(zhi)造(zao)的(de)，而(er)英(ying)制(zhi)鋼(gang)管(guan)(guan)(guan)(guan)(guan)則是(shi)按ASME B36.10《焊接(jie)(jie)和(he)無(wu)縫(feng)(feng)軋制(zhi)鋼(gang)管(guan)(guan)(guan)(guan)(guan)》和(he)ASME B36.19《不銹鋼(gang)管(guan)(guan)(guan)(guan)(guan)》標(biao)準(zhun)(zhun)制(zhi)造(zao)的(de)。過去，我國的(de)鋼(gang)管(guan)(guan)(guan)(guan)(guan)規格(ge)分(fen)大(da)外(wai)徑(jing)(jing)系(xi)(xi)(xi)(xi)列和(he)小(xiao)(xiao)(xiao)外(wai)徑(jing)(jing)系(xi)(xi)(xi)(xi)列兩(liang)(liang)種，人們把(ba)大(da)外(wai)徑(jing)(jing)系(xi)(xi)(xi)(xi)列稱為(wei)A系(xi)(xi)(xi)(xi)列，小(xiao)(xiao)(xiao)外(wai)徑(jing)(jing)系(xi)(xi)(xi)(xi)列稱為(wei)B系(xi)(xi)(xi)(xi)列。大(da)外(wai)徑(jing)(jing)系(xi)(xi)(xi)(xi)列管(guan)(guan)(guan)(guan)(guan)子(zi)(zi)(zi)的(de)管(guan)(guan)(guan)(guan)(guan)徑(jing)(jing)和(he)ASME標(biao)準(zhun)(zhun)接(jie)(jie)近。小(xiao)(xiao)(xiao)外(wai)徑(jing)(jing)系(xi)(xi)(xi)(xi)列管(guan)(guan)(guan)(guan)(guan)子(zi)(zi)(zi)的(de)管(guan)(guan)(guan)(guan)(guan)徑(jing)(jing)和(he)當時的(de)俄(e)羅斯(si)標(biao)準(zhun)(zhun)一(yi)致。例如，DN50mm的(de)管(guan)(guan)(guan)(guan)(guan)子(zi)(zi)(zi)，大(da)外(wai)徑(jing)(jing)系(xi)(xi)(xi)(xi)列管(guan)(guan)(guan)(guan)(guan)子(zi)(zi)(zi)的(de)外(wai)徑(jing)(jing)為(wei)60.3mm，而(er)小(xiao)(xiao)(xiao)外(wai)徑(jing)(jing)系(xi)(xi)(xi)(xi)列管(guan)(guan)(guan)(guan)(guan)子(zi)(zi)(zi)的(de)外(wai)徑(jing)(jing)為(wei)57mm；DN100mm的(de)大(da)外(wai)徑(jing)(jing)系(xi)(xi)(xi)(xi)列的(de)無(wu)縫(feng)(feng)鋼(gang)管(guan)(guan)(guan)(guan)(guan)的(de)外(wai)徑(jing)(jing)為(wei)114mm，小(xiao)(xiao)(xiao)外(wai)徑(jing)(jing)系(xi)(xi)(xi)(xi)列的(de)無(wu)縫(feng)(feng)鋼(gang)管(guan)(guan)(guan)(guan)(guan)的(de)外(wai)徑(jing)(jing)為(wei)108mm。現在，我國無(wu)縫(feng)(feng)鋼(gang)管(guan)(guan)(guan)(guan)(guan)標(biao)準(zhun)(zhun)GB/T 17395《無(wu)縫(feng)(feng)鋼(gang)管(guan)(guan)(guan)(guan)(guan)尺寸(cun)、外(wai)形、重量(liang)及允許(xu)偏差》和(he)ISO4200標(biao)準(zhun)(zhun)有(you)一(yi)定的(de)對應性。
2. 管子系(xi)(xi)列標準，一類是(shi)以表(biao)4.1.6為對應(ying)(ying)外徑尺(chi)寸的所謂(wei)“大外徑”系(xi)(xi)列；另(ling)一類則是(shi)以表(biao)4.1.7為對應(ying)(ying)外徑尺(chi)寸的所謂(wei)“小外徑”系(xi)(xi)列。
注：①. 在英制(zhi)單(dan)位轉化(hua)為公制(zhi)單(dan)位時(shi)約去了小數點。
②. 定義不確切，但已是(shi)多年來的習慣叫(jiao)法，不妨(fang)仍這樣叫(jiao)。“小外(wai)徑(jing)”的概念也是(shi)如此。
3. ISO4200標(biao)準把鋼(gang)(gang)管(guan)(guan)(guan)(guan)(guan)分(fen)成(cheng)三個(ge)系列(lie)(lie)，三個(ge)系列(lie)(lie)的(de)管(guan)(guan)(guan)(guan)(guan)外(wai)徑(jing)均不一(yi)樣(yang)。第一(yi)系列(lie)(lie)內的(de)鋼(gang)(gang)管(guan)(guan)(guan)(guan)(guan)有(you)標(biao)準化附(fu)(fu)件配用(yong)(yong)。第二系列(lie)(lie)則(ze)是(shi)沒有(you)齊(qi)全(quan)的(de)附(fu)(fu)件標(biao)準。第三系列(lie)(lie)是(shi)特殊用(yong)(yong)途鋼(gang)(gang)管(guan)(guan)(guan)(guan)(guan)，有(you)很少量附(fu)(fu)件標(biao)準。ISO4200標(biao)準第一(yi)系列(lie)(lie)鋼(gang)(gang)管(guan)(guan)(guan)(guan)(guan)，其中有(you)A～G7種(zhong)優先選用(yong)(yong)壁厚(hou)，D、E、F和(he)(he)G壁厚(hou)常用(yong)(yong)于非(fei)合金和(he)(he)合金鋼(gang)(gang)材；A、B、C、E、F和(he)(he)G則(ze)常用(yong)(yong)于不銹鋼(gang)(gang)鋼(gang)(gang)管(guan)(guan)(guan)(guan)(guan)。GB／T17395標(biao)準則(ze)把鋼(gang)(gang)管(guan)(guan)(guan)(guan)(guan)分(fen)成(cheng)通(tong)(tong)用(yong)(yong)、非(fei)通(tong)(tong)用(yong)(yong)和(he)(he)少數特殊、專用(yong)(yong)鋼(gang)(gang)管(guan)(guan)(guan)(guan)(guan)3個(ge)系列(lie)(lie)，3個(ge)系列(lie)(lie)的(de)鋼(gang)(gang)管(guan)(guan)(guan)(guan)(guan)外(wai)徑(jing)均不相同。通(tong)(tong)用(yong)(yong)系列(lie)(lie)屬于推薦選用(yong)(yong)系列(lie)(lie)，管(guan)(guan)(guan)(guan)(guan)外(wai)徑(jing)和(he)(he)ISO4200標(biao)準第一(yi)系列(lie)(lie)一(yi)致(zhi)，但壁厚(hou)上(shang)限比ISO4200厚(hou)。英制(zhi)管(guan)(guan)(guan)(guan)(guan)和(he)(he)公制(zhi)管(guan)(guan)(guan)(guan)(guan)的(de)特點，見(jian)表(biao)4.1.8。
