Investigation of Decarburization Behaviour during the Sintering of Metal Injection Moulded 420 Stainless Steel

Lou, Jianzhong; Liu, Muyao; He, Hao; Wang, Xinming; Li, Yimin; Ouyang, Xiaoping; An, Chuanfeng

doi:10.3390/met10020211

Cited by 12 publications

(4 citation statements)

References 18 publications

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“…Decarburization is a surface degradation phenomenon that involves the removal of carbon at the near top surface area of a steel during exposure to air at an elevated temperature and defined time as temperature-time-related processes [1]. This loss can largely influence the material properties of the material surfaces, such as lower strength, lower wear resistance, and lower fatigue resistance [2,3]. Decarburization remains a persistent problem in high-temperature heat treatment processes in industrial operations such as forging and rolling.…”

Section: Introductionmentioning

confidence: 99%

Decarburization in Laser Surface Hardening of AISI 420 Martensitic Stainless Steel

2023

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Decarburization deteriorates the surface mechanical properties of steel. It refers to the loss of carbon from steel’s surface when exposed to an open-air environment in elevated-temperature conditions. Despite the short interaction time and fast thermal cycle of the laser surface-hardening process, decarburization may still occur. This paper investigates if decarburization occurs during the laser surface hardening of AISI 420 martensitic stainless steel. For comparison, surface-hardening results and decarburizations in a conventional air furnace-heated hardening process (water-quenched and air-cooled) of the same steel material were also investigated. Decarburization seems to have occurred in the laser surface hardening of AISI 420SS. However, the decarburization might not be significant, as the hardness of the steel’s surface was increased more than three times to 675 HV during the laser surface hardening, and the hardness drop due to decarburization was estimated to be only 3% with the decarburization depth of 40 μm. Simulations using ThermoCalc software to get the carbon concentration profiles along the depth for both laser-hardened and furnace-heated samples were also investigated.

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Section: Introductionmentioning

confidence: 99%

Decarburization in Laser Surface Hardening of AISI 420 Martensitic Stainless Steel

2023

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“…Several published studies have described the macro and micro decarburization processes that occur in various metallurgical vessels, which can be classified into three types: the converter model, vacuum circulation model (e.g., RH decarburization model), and chromium-preservation model of stainless steel. [11][12][13] However, few studies on decarburization in the VOD process are available in the open literature. Takawa et al [14] developed an end-point control mathematical model in the VOD refining process by using a large number of empirical coefficients and adaptive parameters corrected by industrial production data.…”

Section: Introductionmentioning

confidence: 99%

A Dynamic Decarburization Model in Vacuum Oxygen Decarburization Process for Ultrapure Ferritic Stainless Steel

Wang

Cheng

Zhang

et al. 2023

steel research int.

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A mathematical model incorporating dynamic parameters is proposed to investigate the overall decarburization process during the vacuum oxygen refining (VOD) process for ultrapure ferritic stainless steel. This paper also conducted a precise theoretical calculation of the C‐Cr equilibrium. Moreover, the top‐blowing oxygen distribution is categorized into six directions: [C] oxidation, alloy component oxidation, CO bubble oxidation above the bath surface, bath surface oxidation (FeO), dissolution in the molten steel ([O]), and escape into the exhausted gas. The FeO and Cr2O3 oxide are intermediate product of oxygen to oxidize [C] remaining in the molten steel during the VCD stage. The modified approach of Gibbs free energies determines the critical carbon concentration by the distribution ratio of carbon to the top‐blowing oxygen. The top‐blowing oxygen primarily consumed by CO‐CO2 bubble (49–55%) and Cr2O3 (26–33%). Additionally, the model considered operational aspects, the system's heat balance, and changes in overall metal‐slag conditions during the refining process. The exhausted gas composition and end‐point carbon concentration align well with industrial data. Within a certain range (approximately up to 0.50%), increasing initial carbon concentration can enhance overall decarburization efficiency.

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“…At high temperatures, the diffusion rate of carbon is so large that a significant amount of carbon loss may occur in regions adjacent to the surface [ 2 , 3 ]. Decarburization results in poor material properties, such as lower strength, poor wear resistance, and reduced fatigue life [ 4 , 5 , 6 ]. Decarburization remains a persistent problem in the manufacturing industry for processes that involve high-temperature heat treatment of steels [ 7 ].…”

Section: Introductionmentioning

confidence: 99%

Decarburization of Wire-Arc Additively Manufactured ER70S-6 Steel

et al. 2023

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Decarburization is an unwanted carbon-loss phenomenon on the surfaces of a material when they are exposed to oxidizing environments at elevated temperatures. Decarburization of steels after heat treatment has been widely studied and reported. However, up to now, there has not been any systematic study on the decarburization of additively manufactured parts. Wire-arc additive manufacturing (WAAM) is an efficient additive manufacturing process for producing large engineering parts. As the parts produced by WAAM are usually large in size, the use of a vacuum environment to prevent decarburization is not always feasible. Therefore, there is a need to study the decarburization of WAAM-produced parts, especially after the heat treatment processes. This study investigated the decarburization of a WAAM-produced ER70S-6 steel using both the as-printed material and samples heat-treated at different temperatures (800 °C, 850 °C, 900 °C, and 950 °C) for different durations (30 min, 60 min, and 90 min). Furthermore, numerical simulation was carried out using Thermo-Calc computational software to predict the carbon concentration profiles of the steel during the heat treatment processes. Decarburization was found to occur not only in the heat-treated samples but also on the surfaces of the as-printed parts (despite the use of Ar for shielding). The decarburization depth was found to increase with an increase in heat treatment temperature or duration. The part heat-treated at the lowest temperature of 800 °C for merely 30 min was observed to have a large decarburization depth of about 200 μm. For the same heating duration of 30 min, an increase in temperature of 150 °C to 950 °C increased the decarburization depth drastically by 150% to 500 μm. This study serves well to demonstrate the need for further study to control or minimize decarburization for the purpose of ensuring the quality and reliability of additively manufactured engineering components.

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Investigation of Decarburization Behaviour during the Sintering of Metal Injection Moulded 420 Stainless Steel

Cited by 12 publications

References 18 publications

Decarburization in Laser Surface Hardening of AISI 420 Martensitic Stainless Steel

Decarburization in Laser Surface Hardening of AISI 420 Martensitic Stainless Steel

A Dynamic Decarburization Model in Vacuum Oxygen Decarburization Process for Ultrapure Ferritic Stainless Steel

Decarburization of Wire-Arc Additively Manufactured ER70S-6 Steel

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