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High-chromium ferrite heat-resistant steel fine-deformation martensite lath microstructure refinement method

A technology of high-chromium ferrite and heat-resistant steel, which is applied in the field of micro-deformed martensitic lath structure refinement of high-chromium ferrite heat-resistant steel, which can solve the problems of deterioration of metal high-temperature performance and affecting equipment safety, etc.

Inactive Publication Date: 2009-08-19
TIANJIN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The heat-resistant steel in the boiler tube works under high temperature, high pressure and steam corrosion for a long time, the structure and performance of the steel will change, which will obviously deteriorate the high temperature performance of the metal, thus affecting the safety of equipment operation

Method used

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  • High-chromium ferrite heat-resistant steel fine-deformation martensite lath microstructure refinement method
  • High-chromium ferrite heat-resistant steel fine-deformation martensite lath microstructure refinement method
  • High-chromium ferrite heat-resistant steel fine-deformation martensite lath microstructure refinement method

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0021] Example 1: Corresponding high-chromium ferritic heat-resistant steel

[0022] The chemical composition range of the high-chromium ferritic heat-resistant steel used in the experiment is shown in Table 1. The purity of the raw materials used are all higher than 99%. According to the predetermined composition ratio, they are smelted in an electric arc furnace or an induction furnace and undergo two processes of vacuum refining and out-of-furnace refining, and then they are hot-rolled into pipes or plates.

[0023] Take the sample of the same composition after fusion, and cut a cylindrical sample from the steel pipe by wire cutting. The size of the linear expansion sample is 5mm in diameter and 10mm in length; after cleaning and drying, put it in a high-frequency induction heat treatment device for treatment: set The fixed program is as follows: the heating rate is 30-80K / min, after rising from room temperature to 1223-1323K, keeping the temperature for 5-15 minutes, then ...

Embodiment 2

[0024] Example 2: Corresponding to T91 high-chromium ferritic heat-resistant steel

[0025] (1) Sample preparation

[0026] The purity of the raw materials used is all higher than 99%. According to the established composition ratio in Table 2 (corresponding to T91 high-chromium ferritic heat-resistant steel), it is melted in an electric arc furnace or an induction furnace, and two processes of vacuum refining and out-of-furnace refining are carried out. Then it is hot-rolled into pipe or plate (wall thickness 1.5 cm).

[0027] Table 2 Chemical composition range of T91 high-chromium ferritic heat-resistant steel

[0028] component Content (wt.%) C 0.09 Si 0.03 Cr 9.1 Mo 1.1 mn 0.4 V 0.2 Nb 0.07 N 0.04 Al 0.01

[0029] (2) micro-deformation treatment

[0030] Put the sample into a high-frequency induction heat treatment device for processing: set the program as follows: the heating rate is 50K / min, after rising ...

Embodiment 3

[0032] Example 3: Corresponding to T92 high-chromium ferritic heat-resistant steel

[0033] (1) Sample preparation

[0034] The purity of the raw materials used are all higher than 99%. According to the established composition ratio in Table 3 (corresponding to T92 high-chromium ferritic heat-resistant steel), they are smelted in an electric arc furnace or an induction furnace, and two processes of vacuum refining and out-of-furnace refining are carried out. Then it is hot-rolled into pipe or plate (wall thickness 1.5 cm).

[0035] Table 3 Chemical composition range of T92 high-chromium ferritic heat-resistant steel

[0036] component Content (wt.%) C 0.08 Si 0.03 Cr 9.1 Mo 0.4 mn 0.4 V 0.2 Nb 0.05 N 0.04 Al 0.01

[0037] W 1.0 B 0.05

[0038] (2) micro-deformation treatment

[0039] Put the sample into a high-frequency induction heat treatment device for processing: set the program as follow...

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Abstract

The invention relates to a method for refining the micro-deformation martensitic lath microstructure of high-chromium (Cr) ferrite heat-resistant steel, comprising the following steps: the high-chromium (Cr) ferrite heat-resistant steel is hot-rolled into tubes or plates, and is generally produced into samples with the wall thickness being not larger than 6cm to be ensured to reach required heating and cooling rate; the method is characterized in that the samples are placed in a high-frequency induction heat-treating device for treatment, wherein, the procedures are set as follows: setting the heating rate as 30 to 80 K / min; preserving temperatrue for 5 to 15min after the temperature rises from room temperature to 1,223 to 1,323 K; further cooling to 1,023 to 1,073 K at a cooling rate equal to the heating rate; carrying out slight compressive stress deformation, loading for 3 to 10 s and then unloading immediately, wherein, the stress loaded is 10 to 40 MPa; and then, cooling to the room temperature at the rate equal to the cooling rate. Compared with the conventional method for refining the martensitic lath microstructure, which is characterized in that the deformation is formed by increasing the stress, the method of the invention for refining alloy grains has the advantages of small loaded stress and short loading time; the energy consumption is much lower than that of the conventional method; furthermore, the high-temperature performance of the alloy is much improved, therefore, the method is a potential and practical manufacturing method.

Description

technical field [0001] The invention belongs to the technical field of high-chromium ferritic heat-resistant steel production, and particularly relates to a method for refining the structure of micro-deformed martensitic laths of high-chromium ferritic heat-resistant steel. Background technique [0002] The development of heat-resistant steel is closely related to the progress of energy, power and machinery industries. In the fields of thermal power generation, nuclear energy, aerospace, aviation, petroleum and chemical industry, the performance of heat-resistant steel is the key to success. In recent years, in order to solve the increasingly prominent energy shortage and environmental pollution problems, high-efficiency power generation has become a hot topic. In order to improve thermal efficiency, the parameters of thermal power generating units in various countries in the world are developing towards super (super) critical parameters. Improving thermal efficiency is mai...

Claims

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Application Information

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IPC IPC(8): C21D8/00C21D1/42C21D8/02C21D8/10
CPCY02P10/25
Inventor 刘永长严泽生刘晨曦高志明宁保群
Owner TIANJIN UNIV
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