Method for improving hydrogen resistance of iron-nickel-based alloy by increasing special grain boundary ratio

An iron-nickel-based alloy and special grain boundary technology, which is applied in the field of iron-nickel-based alloys, can solve problems such as cracking and hydrogen resistance degradation, achieve optimal room temperature mechanical properties, increase initiation and expansion resistance, and improve hydrogen damage resistance. Effect

Active Publication Date: 2018-12-14
INST OF METAL RESEARCH - CHINESE ACAD OF SCI
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Problems solved by technology

[0008] The purpose of the present invention is to provide a method for improving the hydrogen resistance of iron-nickel-based alloys by increasing the proportion of special grain boundaries, so as to solve the problem that the existing iron-nickel-based alloys are prone to form hydrogen and cause cracking along the grain boundaries, resulting in a decrease in hydrogen resistance

Method used

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  • Method for improving hydrogen resistance of iron-nickel-based alloy by increasing special grain boundary ratio
  • Method for improving hydrogen resistance of iron-nickel-based alloy by increasing special grain boundary ratio
  • Method for improving hydrogen resistance of iron-nickel-based alloy by increasing special grain boundary ratio

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Embodiment 1

[0033] In this embodiment, the J75 alloy plate with a thickness of 3.0mm is subjected to thermomechanical treatment, and the proportion of special grain boundaries reaches 75%, which improves the hydrogen damage resistance of the alloy. The specific implementation process is:

[0034] 1. The J75 alloy sheet is a hot-rolled sheet, and the chemical composition of the hot-rolled sheet meets the requirements of GJB 5724-2006 "Specification for Hydrogen-Resistant Steel Bars". The J75 alloy plate is placed in a heat treatment furnace, kept at 970-990°C (980°C in this embodiment) for 0.5-2h (1h in this embodiment), and taken out for water quenching;

[0035] 2. Using a four-roll cold rolling mill, the J75 alloy plate after solution treatment in step 1 is subjected to 4-6% (4.3% in this embodiment) cold rolling deformation.

[0036] 3. The J75 alloy plate after the cold rolling and deformation in step 2 is subjected to heat preservation treatment. The method is to keep warm for 20 to...

Embodiment 2

[0049] The difference from Example 1 is that the thickness of the J75 alloy plate used is 3.8mm, the pre-deformation is 6%, and the holding time is 1000°C and 40min, the proportion of special grain boundaries in the alloy is 72.4%.

[0050] A 3.8 mm thick J75 alloy hot-rolled plate with the same chemical composition as in Example 1 was used for thermomechanical treatment. Heat preservation at 980°C for 1 hour, followed by water quenching; after 6% cold rolling deformation, heat preservation treatment at 1000°C for 40 minutes, and then water cooling to room temperature. The samples after thermomechanical treatment were kept at 720°C for 16h, and then air-cooled to room temperature. EBSD was used to analyze the grain boundary structure, and the results showed that the proportion of special grain boundaries in the alloy reached 72.4%, and the connectivity of large-angle random grain boundaries was interrupted. The J75 alloy plate according to figure 2 Process the tensile speci...

Embodiment 3

[0058] The difference from Example 1 is that the selected J75 alloy sheet has a thickness of 4mm, 5% pre-deformation, and heat preservation treatment at 1000°C for 25 minutes, and the proportion of special grain boundaries is 77.4%.

[0059] A 4 mm thick J75 alloy hot-rolled plate with the same chemical composition as in Example 1 was used for thermomechanical treatment. Insulate at 980°C for 2 hours, then water quenching; after 5% cold rolling deformation, perform heat preservation at 1000°C for 25min, then take out the water and cool to room temperature. The samples after thermomechanical treatment were kept at 720°C for 16h, and then air-cooled to room temperature. EBSD was used to analyze the grain boundary structure, and the results showed that the proportion of special grain boundaries in the alloy reached 77.4%, and the connectivity of large-angle random grain boundaries was interrupted. The J75 alloy plate according to figure 2 Process the tensile specimens, and per...

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Abstract

The invention relates to the field of iron-nickel-based alloy, in particular to a method for improving the hydrogen resistance of iron-nickel-based precipitation-strengthened austenite alloy by increasing the special grain boundary ratio, and solves the problems that after saturated hydrogenation of the existing iron-nickel-based alloy, hydrogen-induced grain boundary cracks are easily formed andhydrogen embrittlement sensitivity increase and elongation decrease are caused thereby. By a thermal mechanical treatment (single-step deformation heat treatment) method, the special grain boundary ratio of the alloy is increased, the initiation and expansion resistance of the hydrogen-induced cracks in the alloy is increased, and the hydrogen damage resistance of the alloy is improved; the methodcomprises the following specific technological route: performing solution treatment, predeforming, preserving heat, performing water cooling, performing aging treatment and performing air cooling. The iron-nickel-based alloy treated by the method provided by the invention has the special grain boundary ratio of 65-80% and has the room-temperature tensile elongation of 33% or above; after saturated thermal hydrogenation, the room-temperature elongation of the alloy can still keep 30% or above, and the hydrogen-induced elongation loss is reduced within 10%.

Description

technical field [0001] The invention relates to the field of iron-nickel-based alloys, in particular to a method for improving the hydrogen resistance of iron-nickel-based precipitation-strengthened austenitic alloys by increasing the special (low coincidence position lattice Σ≤29) grain boundary ratio Background technique [0002] Austenitic anti-hydrogen embrittlement alloys have been widely used in energy, chemical, national defense and nuclear fields. Among the austenitic hydrogen embrittlement-resistant alloys, the single-phase austenitic alloy has the best hydrogen resistance, but its strength is not high, and its yield strength (σ 0.2 ) is generally ~ 200MPa, and the high one is only 450 ~ 500MPa. Precipitation-strengthened iron-nickel-based austenitic hydrogen-resistant alloys (hereinafter referred to as iron-nickel-based alloys) are developed on the basis of single-phase austenitic alloys by adding alloying elements. The precipitation strengthening effect in the a...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C21D8/02
CPCC21D8/0236C21D8/0247
Inventor 赵明久胡红磊戎利建
Owner INST OF METAL RESEARCH - CHINESE ACAD OF SCI
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