Economical hydrigen gas transportation pipeline steel, and production method

Abstract

An economical hydrogen gas transportation pipeline steel comprises the following components in percentage by weight: 0.03-0.08% C. 0.15% or less Si, 0.53-1.19% Mn, 0.012% or less P. 0.0015% or less S, 0.010-0.080% Ti, 0.025-0.048% Al, 0.0045% or less N, and 0.002% or less O. A method comprises: casting a steel into a slab after smelting; heating the slabs; rough rolling; finishing rolling; cooling; and coiling. The yield strength of the steel of the present invention is 298-507 MPa, heat treatment is not needed, the production and manufacturing processes are shortened, and overall energy consumption is reduced.

1 . An economical hydrogen gas transportation pipeline steel, characterized by comprising the following components in percentage by weight:
 0.03-0.08% C, 0.15% or less Si, 0.53-1.19% Mn, 0.012% or less P, 0.0015% or less S, 0.010-0.080% Ti, 0.025-0.048% Al, 0.0045% or less N, and 0.002% or less O, the balance being Fe and unavoidable impurities.   
     
     
         2 . The economical hydrogen gas transportation pipeline steel according to  claim 1 , characterized in that the weight percentage content of Ti is 0.019-0.073%. 
     
     
         3 . The economical hydrogen gas transportation pipeline steel according to  claim 1 , characterized in that the weight percentage content of S is 0.0012% or less. 
     
     
         4 . The economical hydrogen gas transportation pipeline steel according to  claim 1 , characterized in that the weight percentage content of N is 0.0041% or less. 
     
     
         5 . The economical hydrogen gas transportation pipeline steel according to  claim 1 , characterized in that 0.30% or less Cr or 0.20% or less Mo or 0.04% or less Nb or a combination of two or more thereof is added. 
     
     
         6 . A method for producing the economical hydrogen gas transportation pipeline steel according to  claim 1 , characterized by the steps of:
 1) casting a steel into a slab after smelting, with composition adjustment controlled to be completed during a LF refining stage;   2) heating the slab, wherein the surface and average temperatures should be no less than 650° C. and 700° C., respectively, while ensuring that a phase transformation rate does not exceed 8% during charging a furnace; alternatively, the slab may be cooled slowly by stacking to 500° C. or below before being charged into a furnace, in which case the phase transformation rate must exceed 92%; the heating temperature is controlled between 1200° C. and 1280° C.;   3) performing rough rolling, wherein a total reduction rate of the rough rolling is controlled to be not less than 80%, and a reduction rate of last two passes of the rough rolling is controlled to be not less than 23%;   4) performing finishing rolling: wherein a total reduction rate of the finishing rolling is controlled to be 60-85%, and a reduction rate of last two passes is controlled to be 10% or less; and the final rolling temperature is controlled to be 860-920° C.;   5) performing cooling, namely performing cooling at a cooling rate of 10-40° C./s to the coiling temperature; and   6) performing coiling, wherein the coiling temperature is controlled to be 550-700° C.   
     
     
         7 . The method for producing the economical hydrogen gas transportation pipeline steel according to  claim 6 , characterized in that a phase transformation rate of the slab is controlled to not exceed 5% when entering the furnace.