Hydrogen-carrying pipe component

Abstract

A hydrogen-carrying, cold-drawn pipe component made of a steel alloy which, in addition to iron and smelting-related contaminants, includes the following elements in mass-%: C: 0.07-0.22, Si: 0.10-0.55, Mn: 0.30-1.60, P: ≤0.025, S: ≤0.015, Ti: 0.010-0.030, V: 0.003-0.30, N: 0.008-0.025, Al: 0.010-0.025, Ca: <0.10, and optionally: Nb: ≤0.10, Mo: ≤0.50, Cr: ≤0.50, Ni: ≤1.0, Cu: ≤0.20. The microstructure contains more than 95% ferrite+perlite, having a grain size of the grain size class 9 or finer according to ASTM E112-13(2021), in particular at least 10, wherein the remainder of the microstructure includes martensite, bainite, and residual austenite. The pipe component has a tensile strength of at least 340 MPa, advantageously of 400-850 MPa.

What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims and includes equivalents of the elements recited therein: 
     
         1 . A hydrogen-carrying, cold-drawn pipe component made of a steel alloy which, in addition to iron and smelting-related contaminants, comprises the following elements in mass-%:
 C: 0.07-0.22   Si: 0.10-0.55   Mn: 0.30-1.60   P: ≤0.025   S: ≤0.015   Ti: 0.010-0.030   V: 0.003-0.30   N: 0.008-0.025   Al: 0.010-0.025   Ca <0.1   and optionally:   Nb: ≤0.10   Mo: ≤0.50   Cr: ≤0.50   Ni: ≤1.0   Cu: ≤0.20,   wherein a microstructure contains greater than 95% ferrite+perlite, having a grain size of the grain size class 9 or finer according to ASTM E112-13(2021), wherein the remainder of the microstructure contains martensite, bainite, and residual austenite, wherein the pipe component has a tensile strength of at least 340 MPa.   
     
     
         2 . The hydrogen-carrying, cold-drawn pipe component of  claim 1 , wherein the steel alloy comprises, in addition to iron and smelting-related contaminants, the following elements in mass-%:
 C: 0.07-0.22   Si: 0.10-0.55   Mn: 0.30-0.7   P: 0.005-0.025   S: 0.002-0.015   Ti: 0.010-0.030   V: 0.003-0.30   N: 0.008-0.025   Al: 0.010-0.025   Ca 0.0005-0.050   and optionally:   Nb: ≤0.050   Mo: ≤0.30   Cr: ≤0.35.   
     
     
         3 . The hydrogen-carrying, cold-drawn pipe component of  claim 1 , wherein the steel alloy comprises, in addition to iron and smelting-related contaminants, the following elements in mass-%:
 C: 0.09-0.22   Si: 0.10-0.55   Mn: 0.70-1.60   P: 0.005-0.025   S: 0.002-0.015   Ti: 0.010-0.030   V: 0.050 0.30   N: 0.008-0.025   Al: 0.015-0.025   Ca: 0.0005-0.050   and optionally   Nb: ≤0.050   Mo: ≤0.30   Cr: ≤0.50   Ni: ≤0.50   Cu: ≤0.20.   
     
     
         4 . The hydrogen-carrying, cold-drawn pipe component of  claim 1 , wherein the steel alloy comprises, in addition to iron and smelting-related contaminants, the following elements in mass-%:
 C: 0.09-0.19   Si: 0.20-0.55   Mn: 0.90-1.50   P: 0.005-0.025   S: 0.003-0.015   Ti: 0.010-0.030   V: 0.011-0.30   N: 0.008-0.025   Al: 0.015-0.025   Ca: 0.0010-0.010   and optionally   Nb: ≤0.050   Mo: ≤0.30   Cr: ≤0.50   Ni: ≤0.50   Cu: ≤0.180.   
     
     
         5 . The hydrogen-carrying, cold-drawn pipe component of  claim 1 , wherein the steel alloy comprises, in addition to iron and smelting-related contaminants, the following elements in mass-%:
 C: 0.07-0.17   Si: 0.10-0.55   Mn: 0.70-1.60   P: 0.005-0.025   S: 0.002-0.015   Ti: 0.010-0.030   V: 0.003-0.30   N: 0.008-0.025   Al: 0.010-0.025   Ca: 0.0005-0.050   and optionally   Nb: ≤0.050   Mo: ≤0.30   Cr: ≤0.35.   
     
     
         6 . The hydrogen-carrying, cold-drawn pipe component of  claim 1 , wherein the steel alloy has a carbon equivalent value CEV≤0.42 calculated according to the following equation CEV=C+Mn/6+(Cu+Ni)/15+(Cr+Mo+V)/5. 
     
     
         7 . The hydrogen-carrying, cold-drawn pipe component of  claim 1 , wherein the pipe component has a yield strength Rp0.2≥220 MPa and an elongation at fracture A≥25%. 
     
     
         8 . The hydrogen-carrying, cold-drawn pipe component of  claim 1 , wherein on one side of the pipe component, in particular on a non-hydrogen-carrying side, at least one coating produced by dipping and/or galvanically and/or a coating applied by electrophoretic deposition and/or a coating produced by powder lacquering is applied. 
     
     
         9 . The hydrogen-carrying, cold-drawn pipe component of  claim 1 , wherein in a burst pressure test according to ISO 11114-4:2017 method A, the burst pressure of a sample of the steel material of the pipe component with the test gas helium in relation to the burst pressure with the test gas hydrogen is at most 2. 
     
     
         10 . The hydrogen-carrying, cold-drawn pipe component of  claim 1 , wherein a cyclic pressure test is carried out using hydrogen gas over 50,000 pressure cycles at a testing temperature of −60° C., wherein a pressure cycle comprises 20 to 30 seconds and wherein in each pressure cycle the pressure is increased from 0 to 87.5 MPa and reduced again to 0 MPa, wherein subsequently a burst pressure test is carried out under the conditions cited in ISO 11114-4:2017, wherein an unloaded pipe component as a reference pipe is compared to a pipe sample after the cyclic pressure test, wherein the determined burst pressure of the pipe sample in comparison to the reference pipe is at most 40% lower. 
     
     
         11 . The hydrogen-carrying, cold-drawn pipe component of  claim 1 , wherein the pipe component has a pressure resistance with hydrogen gas of at least 80 MPa. 
     
     
         12 . The hydrogen-carrying, cold-drawn pipe component of  claim 1 , wherein the steel alloy comprises vanadium carbon nitride precipitates, wherein the vanadium carbon nitride precipitates have a maximum equivalence diameter 60 nm and wherein the mean equivalence diameter is 10 nm or less. 
     
     
         13 . The hydrogen-carrying, cold-drawn pipe component of  claim 1 , wherein the pipe component comprises a microstructure which is hot-rolled and cold-drawn, and subsequently optionally normalized once or twice, wherein the component is in particular produced without weld seams. 
     
     
         14 . The hydrogen-carrying, cold-drawn pipe component of  claim 1 , wherein the pipe component is a hydrogen-carrying line or a hydrogen tank, wherein the hydrogen tank has at least one end section closed by forming and/or materially-bonded joining. 
     
     
         15 . The hydrogen-carrying, cold-drawn pipe component of  claim 1 , wherein the grain size is of the grain size class of at least 10 or finer according to ASTM E112-13(2021), and wherein the remainder of the microstructure includes martensite, bainite, and residual austenite, wherein the pipe component has a tensile strength of 400-850 MPa. 
     
     
         16 . The hydrogen-carrying, cold-drawn pipe component of  claim 9 , wherein the burst pressure of a sample of the steel material of the pipe component with the test gas helium in relation to the burst pressure with the test gas hydrogen is at most 1.75. 
     
     
         17 . The hydrogen-carrying, cold-drawn pipe component of  claim 9 , wherein the burst pressure of a sample of the steel material of the pipe component with the test gas helium in relation to the burst pressure with the test gas hydrogen is at most 1.5. 
     
     
         18 . The hydrogen-carrying, cold-drawn pipe component of  claim 9 , wherein the burst pressure of a sample of the steel material of the pipe component with the test gas helium in relation to the burst pressure with the test gas hydrogen is at most 1.2. 
     
     
         19 . The hydrogen-carrying, cold-drawn pipe component of  claim 10 , wherein an unloaded pipe component as a reference pipe is compared to a pipe sample after the cyclic pressure test, wherein the determined burst pressure of the pipe sample in comparison to the reference pipe is at most 30% lower, in particular at most 20% lower. 
     
     
         20 . The hydrogen-carrying, cold-drawn pipe component of  claim 10 , wherein an unloaded pipe component as a reference pipe is compared to a pipe sample after the cyclic pressure test, wherein the determined burst pressure of the pipe sample in comparison to the reference pipe is at most 10% lower.