Toughening of AISI 410 Stainless Steel Through Quenching and Partitioning and Effect of Prolonged Aging on Microstructure and Mechanical Properties

High boron steel is prone to brittle failure due to the boride distributed in it with net-like or fishbone morphology, which limit its applications. The Quenching and Partitioning (Q&P) heat treatment is a promising process to produce martensitic steel with excellent mechanical properties, especially high toughness by increasing the volume fraction of retained austensite (RA) in the martensitic matrix. In this work, the Q&P heat treatment is used to improve the inherent defect of insufficient toughness of high boron steel, and the effect mechanism of this process on microstructure transformation and the change of mechanical properties of the steel has also been investigated. The high boron steel as-casted is composed of martensite, retained austensite (RA) and eutectic borides. A proper quenching and partitioning heat treatment leads to a significant change of the microstructure and mechanical properties of the steel. The net-like and fishbone-like boride is partially broken and spheroidized. The volume fraction of RA increases from 10% in the as-cast condition to 19%, and its morphology also changes from blocky to film-like. Although the macro-hardness has slightly reduced, the toughness is significantly increased up to 7.5 J·cm−2, and the wear resistance is also improved.

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Effect of energy density and scanning strategy on densification, microstructure and mechanical properties of 316L stainless steel processed via selective laser melting

Materials Science and Engineering A ◽

10.1016/j.msea.2019.138455 ◽

2020 ◽

Vol 770 ◽

pp. 138455 ◽

Cited By ~ 19

Author(s):

Taban Larimian ◽

Manigandan Kannan ◽

Dariusz Grzesiak ◽

Bandar AlMangour ◽

Tushar Borkar

Keyword(s):

Mechanical Properties ◽

Stainless Steel ◽

Energy Density ◽

Selective Laser Melting ◽

316L Stainless Steel ◽

Laser Melting ◽

Scanning Strategy ◽

Microstructure And Mechanical Properties

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Microstructure and Mechanical Properties of Heat-Affected Zone of Repeated Welding AISI 304N Austenitic Stainless Steel by Gleeble Simulator

Metals ◽

10.3390/met8100773 ◽

2018 ◽

Vol 8 (10) ◽

pp. 773

Author(s):

Y.H. Guo ◽

Li Lin ◽

Donghui Zhang ◽

Lili Liu ◽

M.K. Lei

Keyword(s):

Mechanical Properties ◽

Stainless Steel ◽

Austenitic Stainless Steel ◽

Impact Energy ◽

Heat Affected Zone ◽

Ferrite Content ◽

Equipment Safety ◽

Microstructure And Mechanical Properties ◽

Δ Ferrite ◽

The Impact

Heat-affected zone (HAZ) of welding joints critical to the equipment safety service are commonly repeatedly welded in industries. Thus, the effects of repeated welding up to six times on the microstructure and mechanical properties of HAZ for AISI 304N austenitic stainless steel specimens were investigated by a Gleeble simulator. The temperature field of HAZ was measured by in situ thermocouples. The as-welded and one to five times repeated welding were assigned as-welded (AW) and repeated welding 1–5 times (RW1–RW5), respectively. The austenitic matrices with the δ-ferrite were observed in all specimens by the metallography. The δ-ferrite content was also determined using magnetic and metallography methods. The δ-ferrite had a lathy structure with a content of 0.69–3.13 vol.%. The austenitic grains were equiaxial with an average size of 41.4–47.3 μm. The ultimate tensile strength (UTS) and yield strength (YS) mainly depended on the δ-ferrite content; otherwise, the impact energy mainly depended on both the austenitic grain size and the δ-ferrite content. The UTS of the RW1–RW3 specimens was above 550 MPa following the American Society of Mechanical Engineers (ASME) standard. The impact energy of all specimens was higher than that in ASME standard at about 56 J. The repeated welding up to three times could still meet the requirements for strength and toughness of welding specifications.

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