Creepage stage determination systems and methods for aluminum-containing heat-resistant alloy furnace tubes

A creep stage determination method for an aluminum-containing heat-resistant alloy furnace tube at a temperature of 1100° C., comprising:

• S1, performing microstructural observation and analysis at a 1/4-3/4 wall thickness part of a cross-section of the aluminum-containing heat-resistant alloy furnace tube, including:
• measuring an area S1 of a peripheral lumpy precipitate M23C6-type carbide in an austenitic grain boundary precipitate of a furnace tube material within a field-of-view area S0, and determining an area fraction of the area S1 of the peripheral lumpy precipitate M23C6-type carbide in the austenitic grain boundary precipitate to the field-of-view area S0 as A=S1/S0×100%, with a unit of 1;
• measuring an area S2 of an internal thin strip-like precipitate M7C3-type carbide in the austenitic grain boundary precipitate of the furnace tube material within the field-of-view area S0, and determining an area fraction of the area S2 of the internal thin strip-like precipitate M7C3-type carbide in the austenitic grain boundary precipitate to the field-of-view area S0 as B=S2/S0×100%, with a unit of 1;
• and
• measuring an aspect ratio C of the internal thin strip-like precipitate M7C3-type carbide in the austenitic grain boundary precipitate of the furnace tube material within the field-of-view area S0, with a unit of 1;
• S2, determining an influence function of a creep stage of the aluminum-containing heat-resistant alloy furnace tube at 1100° C. based on the area fractions A and B and the aspect ratio C:
• f
• ⁡
• (
• A
• ,
• B
• ,
• C
• )
• =
• [
• (
• aA
• +
• bB
• +
• cC
• )
• /
• 100
• ]
• ×
• 100
• ⁢
• %
• where a is 1200, b is −10, and c is −0.3;
• S3, dividing the creep stage of the aluminum-containing heat-resistant alloy furnace tube at 1100° C., including:
• if f(A, B, C)≤10%, determining a creep state of a 27Cr44Ni5W3Al+microalloyed furnace tube as a creep first stage;
• if 10%<f(A, B, C)≤30%, determining the creep state of the 27Cr44Ni5W3Al+microalloyed furnace tube as an early phase of the creep second stage;
• if 30%<f(A, B, C)≤70%, determining the creep state of the 27Cr44Ni5W3Al+microalloyed furnace tube as a mid-phase of the creep second stage;
• and
• if 70%<f(A, B, C)≤90%, determining the creep state of the 27Cr44Ni5W3Al+microalloyed furnace tube as an end phase of the creep second stage.