seamless square and rectangular steel tube 1.steel grade: Q195-Q345,S235-S355 2. standard: ASTM A500,EN10219,EN10210 Tianjin Yuanlitai Steel Pipe Co., Ltd.Our Steel Pipe (Customized Products ... , STK490, STK500, STK540, STPG370, STPG410 etc..SurfaceSatiny and Smooth, Oiled or Not, black painted, black varnish, 3PE coating, FBE coating, Bare, varnished, zinc ...