JMAK model applied on the κ-carbide precipitation in FeMnAlC steels

Thermomechanically induced strain is a key variable producing accelerated carbide precipitation, sensitization and stress corrosion cracking in austenitic stainless steels (SS). Recent work has indicated that higher levels of strain (above 20%) also produce transgranular (TG) carbide precipitation and corrosion simultaneous with the grain boundary phenomenon in 316 SS. Transgranular precipitates were noted to form primarily on deformation twin-fault planes and their intersections in 316 SS.Briant has indicated that TG precipitation in 316 SS is significantly different from 304 SS due to the formation of strain-induced martensite on 304 SS, though an understanding of the role of martensite on the process has not been developed. This study is concerned with evaluating the effects of strain and strain-induced martensite on TG carbide precipitation in 304 SS. The study was performed on samples of a 0.051%C-304 SS deformed to 33% followed by heat treatment at 670°C for 1 h.

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Carbide precipitation and chromium depletion on coherent twin boundaries in deformed 304 stainless steels

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100130717 ◽

1992 ◽

Vol 50 (2) ◽

pp. 1216-1217

Author(s):

A.H. Advani ◽

L.E. Murr ◽

D.J. Matlock ◽

W.W. Fisher ◽

P.M. Tarin ◽

...

Keyword(s):

Grain Boundaries ◽

Stainless Steels ◽

Interfacial Free Energy ◽

Carbide Precipitation ◽

Twin Boundaries ◽

Invariant Structure ◽

Heat Treated ◽

Constant Structure ◽

Cr Depletion

Coherent annealing-twin boundaries are constant structure and energy interfaces with an average interfacial free energy of ∼19mJ/m2 versus ∼210 and ∼835mJ/m2 for incoherent twins and “regular” grain boundaries respectively in 304 stainless steels (SS). Due to their low energy, coherent twins form carbides about a factor of 100 slower than grain boundaries, and limited work has also shown differences in Cr-depletion (sensitization) between twin versus grain boundaries. Plastic deformation, may, however, alter the kinetics and thermodynamics of twin-sensitization which is not well understood. The objective of this work was to understand the mechanisms of carbide precipitation and Cr-depletion on coherent twin boundaries in deformed SS. The research is directed toward using this invariant structure and energy interface to understand and model the role of interfacial characteristics on deformation-induced sensitization in SS. Carbides and Cr-depletion were examined on a 20%-strain, 0.051%C-304SS, heat treated to 625°C-4.5h, as described elsewhere.

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Deformation effects on transgranular carbide precipitation in 304 stainless steels

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100121703 ◽

1992 ◽

Vol 50 (1) ◽

pp. 260-261

Author(s):

A.H. Advani ◽

L.E. Murr ◽

D.J. Matlock ◽

W.W. Fisher ◽

P.M. Tarin ◽

...

Keyword(s):

Stainless Steels ◽

True Strain ◽

Carbide Precipitation ◽

Material Research ◽

Chromium Depletion ◽

Engineering Strain ◽

Twin Fault ◽

Heat Treated ◽

Strain Induced Martensite ◽

The Relationship

Plastic deformation is a key variable producing accelerated intergranular (IG) carbide precipitation and chromium-depletion (sensitization) development in stainless steels. Deformation above 20% also produces transgranular (TG) carbides and depletion in the material. Research on TG carbides in SS is, however, limited and has indicated that the precipitation is site-specific preferring twin-fault intersections in 316 SS versus deformation-induced martensite and martensite lath-boundaries in 304 SS. Evidences indicating the relation between martensite and carbides were, however, sketchy.The objective of this work was to fundamentally understand the relationship between TG carbides and strain-induced martensite in 304 SS. Since strain-induced martensite forms at twin-fault intersections in 304 SS and the crystallography of the transformation is well understood, we believed that it could be key in understanding mechanisms of carbides and sensitization in SS. A 0.051% C, 304 SS deformed to ∽33% engineering strain (40% true strain) and heat treated at 670°C/ 0.1-10h was used for the research. The study was carried out on a Hitachi H-8000 STEM at 200 kV.

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AK STEEL TYPE 304L

Alloy Digest ◽

10.31399/asm.ad.ss1324 ◽

2020 ◽

Vol 69 (8) ◽

Keyword(s):

Mechanical Properties ◽

Stainless Steel ◽

Corrosion Resistance ◽

Heat Treating ◽

Stress Relief ◽

Carbide Precipitation ◽

Low Carbon ◽

Steel Type ◽

Temperature Performance ◽

Type 304

Abstract AK Steel Type 304L is a chromium-nickel austenitic stainless steel. It is an extra low-carbon variation of Type 304 with a 0.030% maximum carbon content that eliminates carbide precipitation due to welding. As a result, this alloy can be used in the “as-welded” condition, even in severe corrosive conditions. In many cases it eliminates the necessity of annealing weldments except for applications specifying stress relief. Type 304L has slightly lower mechanical properties than Type 304. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fatigue. It also includes information on high temperature performance, corrosion resistance as well as forming, heat treating, and joining. Filing Code: SS-1324. Producer or Source: AK Steel Corporation.

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AK STEEL TYPE 304

Alloy Digest ◽

10.31399/asm.ad.ss1317 ◽

2020 ◽

Vol 69 (5) ◽

Keyword(s):

Stainless Steel ◽

Carbon Content ◽

Atmospheric Corrosion ◽

Carbide Precipitation ◽

Steel Grade ◽

Good Resistance ◽

Steel Type ◽

Temperature Performance ◽

Type 304 ◽

Lower Carbon

Abstract AK Steel Type 304 is a chromium-nickel austenitic stainless steel. It is a variation of the base 18-8 grade, but with higher chromium and lower carbon content. The lower carbon content minimizes carbide precipitation due to welding and reduces its susceptibility to intergranular corrosion. Type 304 is the most versatile and widely used stainless steel grade. It combines good resistance to atmospheric corrosion and to many chemicals, food, and beverages. It has excellent formability. This datasheet provides information on composition, physical properties, hardness, elasticity, tensile properties as well as fatigue. It also includes information on low and high temperature performance, and corrosion resistance as well as forming and joining. Filing Code: SS-1317. Producer or source: AK Steel Corporation. Originally published April 2020, corrected May 2020.

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REMANIT 4404

Alloy Digest ◽

10.31399/asm.ad.ss0698 ◽

1997 ◽

Vol 46 (10) ◽

Keyword(s):

Stainless Steel ◽

Corrosion Resistance ◽

Physical Properties ◽

Tensile Properties ◽

Heat Treating ◽

Carbide Precipitation ◽

Good Resistance ◽

Corrosion Resistant

Abstract Remanit 4404 is an 18 Cr-8 Ni + molybdenum type corrosion-resistant stainless steel that offers decreased carbide precipitation, and has good resistance to acids. This datasheet provides information on composition, physical properties, elasticity, and tensile properties. It also includes information on corrosion resistance as well as forming and heat treating. Filing Code: SS-698. Producer or source: Thyssen Stahl AG.

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