不銹(xiu)鋼(gang)管(guan)(guan)(guan)(guan)件(jian)在管(guan)(guan)(guan)(guan)系(xi)中(zhong)起著(zhu)改(gai)變(bian)走向、改(gai)變(bian)標高(gao)或改(gai)變(bian)直徑、封閉管(guan)(guan)(guan)(guan)端以(yi)及由主管(guan)(guan)(guan)(guan)上(shang)引(yin)出支管(guan)(guan)(guan)(guan)的作用(yong)。在石油化工裝置中(zhong)管(guan)(guan)(guan)(guan)道品(pin)種(zhong)多(duo)，管(guan)(guan)(guan)(guan)系(xi)復雜(za)、形狀(zhuang)各異、簡繁不等，所用(yong)的管(guan)(guan)(guan)(guan)件(jian)品(pin)種(zhong)、材質、數量也(ye)就很(hen)多(duo)，選(xuan)用(yong)時需要考慮的因(yin)素也(ye)很(hen)復雜(za)。

  非金屬管件和襯里管件的標準化程度不如不銹鋼(gang)管件高，使用時要注意各制造廠在制造工藝、規格尺寸、各種性能等方面的差異。本節主要介紹鋼(gang)制管(guan)件，需要選用非金屬管件和襯里管件時可從有關的標準規范中查找。

  管件的(de)用途見表4-25。

  根據管(guan)(guan)(guan)件(jian)(jian)端部連(lian)接(jie)形式可(ke)將管(guan)(guan)(guan)件(jian)(jian)分(fen)為對焊(han)(han)連(lian)接(jie)管(guan)(guan)(guan)件(jian)(jian)（簡稱(cheng)(cheng)對焊(han)(han)管(guan)(guan)(guan)件(jian)(jian)）、承插焊(han)(han)連(lian)接(jie)管(guan)(guan)(guan)件(jian)(jian)（簡稱(cheng)(cheng)承插焊(han)(han)管(guan)(guan)(guan)件(jian)(jian)）、螺紋連(lian)接(jie)管(guan)(guan)(guan)件(jian)(jian)（簡稱(cheng)(cheng)螺紋管(guan)(guan)(guan)件(jian)(jian)）、法蘭連(lian)接(jie)管(guan)(guan)(guan)件(jian)(jian)以及(ji)其他管(guan)(guan)(guan)件(jian)(jian)。

  壓力管(guan)道設計中，常用(yong)(yong)(yong)對焊(han)管(guan)件、支管(guan)臺、承插焊(han)及螺紋(wen)連接管(guan)件的形式。法(fa)蘭(lan)管(guan)件多用(yong)(yong)(yong)于特殊場合，使用(yong)(yong)(yong)范圍及數量相(xiang)對比較少。需要時可根據《鋼制(zhi)法(fa)蘭(lan)管(guan)件》（GB／T17185）的規定選用(yong)(yong)(yong)。