50x50mm hollow section/SHS/RHS/hollow pipe Standard: BS,ASTM,GB,DIN Grade:Q195-Q345, ... #,45# etc. Mill price Good service 50x50mm hollow section/SHS/RHS/hollow pipe1)Material: Q195/Q215/Q235,Q345,20#,45# etc ... do processing to the Square Pipe.50x50mm hollow section/SHS/RHS/hollow pipe 50x50mm hollow section/SHS ...