Hydrogen Pipeline Steel Composition Without Heat Treatment
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Solution Overview
Problem
Existing hydrogen transportation pipeline steels face challenges in achieving high yield strength and hydrogen resistance while maintaining uniform microstructure and avoiding high production costs, as conventional designs and processes fail to meet the requirements of high-pressure hydrogen transportation.
Innovation Solution
A hydrogen gas transportation pipeline steel with specific chemical composition and controlled production processes, including controlled phase transformation, rolling rates, and cooling rates, to achieve high yield strength without additional heat treatment, ensuring uniform microstructure and enhanced hydrogen resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional normalizing+quenching and tempering process is adopted to achieve high yield strength and hydrogen resistance, then the steel meets acid resistance requirements, but the process cost is high and production cycle is long
Solution Approach 1:
The patent extracts and eliminates the normalizing and tempering heat treatment steps from the conventional production process, retaining only the essential quenching process. This extraction of unnecessary steps directly reduces the production cycle while maintaining the core function of achieving high yield strength and hydrogen resistance through the optimized quenching parameters and steel composition
Solution Approach 2:
The patent changes the chemical composition parameters of the steel, specifically optimizing the content of alloying elements such as Cr, Mn, Mo, and B to achieve the desired mechanical properties and hydrogen resistance. By adjusting these compositional parameters, the steel can attain high yield strength without requiring the full conventional heat treatment process, thus shortening the production cycle
2Reliability
If conventional normalizing+quenching and tempering process is adopted to ensure uniform microstructure and hydrogen resistance, then the steel meets performance requirements, but the process cost increases
Solution Approach 1:
The patent removes the normalizing and tempering steps from the conventional heat treatment process, keeping only the quenching operation. This extraction eliminates the associated costs of additional heating cycles, energy consumption, and production time, while the optimized quenching parameters ensure that the steel still achieves uniform microstructure and adequate hydrogen resistance
Solution Approach 2:
The patent modifies the chemical composition parameters, particularly the content of microalloying elements like Ti, Nb, and V, which enhance hydrogen resistance and strengthen the steel. By changing these compositional parameters, the steel achieves the required reliability for hydrogen service without the need for expensive multi-step heat treatment processes
3Reliability
If low carbon+low manganese composition is adopted to meet acid resistance requirements, then hydrogen resistance is improved, but the yield strength is insufficient for high-pressure hydrogen transportation
Solution Approach 1:
The patent optimizes the chemical composition parameters by precisely controlling the content of carbon (0.22-0.50%), manganese (1.50-3.00%), and particularly the addition of microalloying elements (Ti: 0.010-0.080%, Nb: 0.005-0.050%, V: 0.005-0.050%). These compositional changes enable the steel to achieve both high yield strength (≥485 MPa) and excellent hydrogen resistance, resolving the contradiction between strength and hydrogen resistance
Solution Approach 2:
The patent creates a composite microstructure through the synergistic combination of multiple alloying elements. The interaction between Ti, Nb, V, Cr, Mn, and other elements produces a complex microstructure that simultaneously provides high strength and excellent hydrogen resistance, overcoming the limitations of simple low-carbon-low-manganese compositions
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The steel achieves yield strength of 298-507 MPa with excellent hydrogen resistance and toughness, reducing production costs and energy consumption by eliminating the need for high-energy heat treatment.
Implementation Method 1
controlled phase transformation, rolling rates, and cooling rates, to achieve high yield strength without additional heat treatment, ensuring uniform microstructure
Data Source
AI summary
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.