Retained Austenite Control for the Soft Machining of High-Hardness Tool Steels
Most high-hardness tool steels comprising forming dies require expensive finish machining operations to compensate for the dimensional distortion and surface oxidation caused by the die heat treatment. Precipitation-hardening (PH) tool steels allow for soft finish machining followed by an aging trea...
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MDPI AG
2018-07-01
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| Series: | Metals |
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| Online Access: | http://www.mdpi.com/2075-4701/8/7/564 |
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| author | Maider Muro Garikoitz Artola Josu Leunda Carlos Soriano Carlos Angulo |
| author_facet | Maider Muro Garikoitz Artola Josu Leunda Carlos Soriano Carlos Angulo |
| author_sort | Maider Muro |
| collection | DOAJ |
| description | Most high-hardness tool steels comprising forming dies require expensive finish machining operations to compensate for the dimensional distortion and surface oxidation caused by the die heat treatment. Precipitation-hardening (PH) tool steels allow for soft finish machining followed by an aging treatment without major deformation or oxidation in the die, but exhibit poor wear performance owing to the lack of carbides in their structure. This drawback can be overcome by combining laser cladding technology, austenite retention, and cryogenic treatments. Hence, an alternative die manufacturing route based on laser cladding was explored. The forming surface of a modified chemistry tool steel die was subjected to cladding. The martensite finish (Mf) temperature of the steel was tuned to enhance austenite retention at room temperature. The cladded surface was then machined in a reduced-hardness condition resulting from retained austenite formation. Subsequent deep cryogenic treatment of the die favoured the retained-austenite-to-martensite transformation, thereby increasing the die hardness without major distortion or oxidation. This process combined the advantages of high-carbide-bearing tool steels and PH steels, allowing for a die with hardness exceeding 58 HRC to be finish machined at <52 HRC. Controlling the occurrence of retained austenite represents an effective strategy for achieving new manufacturing scenarios. |
| first_indexed | 2024-04-13T02:18:38Z |
| format | Article |
| id | doaj.art-e94cbe1c7602413ca45ab07983b050a0 |
| institution | Directory Open Access Journal |
| issn | 2075-4701 |
| language | English |
| last_indexed | 2024-04-13T02:18:38Z |
| publishDate | 2018-07-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Metals |
| spelling | doaj.art-e94cbe1c7602413ca45ab07983b050a02022-12-22T03:07:04ZengMDPI AGMetals2075-47012018-07-018756410.3390/met8070564met8070564Retained Austenite Control for the Soft Machining of High-Hardness Tool SteelsMaider Muro0Garikoitz Artola1Josu Leunda2Carlos Soriano3Carlos Angulo4Metallurgy Research Centre IK4 AZTERLAN, Metallurgical Processes, Forming Technology Unit, Aliendalde Auzunea 6, 48200 Durango, SpainMetallurgy Research Centre IK4 AZTERLAN, Metallurgical Processes, Forming Technology Unit, Aliendalde Auzunea 6, 48200 Durango, SpainIK4-Tekniker, Advanced Manufacturing Technologies Unit, Polo Tecnológico de Eibar, Iñaki Goenaga 5, 20600 Eibar, SpainIK4-Tekniker, Advanced Manufacturing Technologies Unit, Polo Tecnológico de Eibar, Iñaki Goenaga 5, 20600 Eibar, SpainDepartment of Mechanical Engineering, University of the Basque Country (UPV/EHU), Plaza Ingeniero Torres Quevedo 1, 48013 Bilbao, SpainMost high-hardness tool steels comprising forming dies require expensive finish machining operations to compensate for the dimensional distortion and surface oxidation caused by the die heat treatment. Precipitation-hardening (PH) tool steels allow for soft finish machining followed by an aging treatment without major deformation or oxidation in the die, but exhibit poor wear performance owing to the lack of carbides in their structure. This drawback can be overcome by combining laser cladding technology, austenite retention, and cryogenic treatments. Hence, an alternative die manufacturing route based on laser cladding was explored. The forming surface of a modified chemistry tool steel die was subjected to cladding. The martensite finish (Mf) temperature of the steel was tuned to enhance austenite retention at room temperature. The cladded surface was then machined in a reduced-hardness condition resulting from retained austenite formation. Subsequent deep cryogenic treatment of the die favoured the retained-austenite-to-martensite transformation, thereby increasing the die hardness without major distortion or oxidation. This process combined the advantages of high-carbide-bearing tool steels and PH steels, allowing for a die with hardness exceeding 58 HRC to be finish machined at <52 HRC. Controlling the occurrence of retained austenite represents an effective strategy for achieving new manufacturing scenarios.http://www.mdpi.com/2075-4701/8/7/564retained austenitelaser claddingcryogenic treatmenttool steelhardness |
| spellingShingle | Maider Muro Garikoitz Artola Josu Leunda Carlos Soriano Carlos Angulo Retained Austenite Control for the Soft Machining of High-Hardness Tool Steels Metals retained austenite laser cladding cryogenic treatment tool steel hardness |
| title | Retained Austenite Control for the Soft Machining of High-Hardness Tool Steels |
| title_full | Retained Austenite Control for the Soft Machining of High-Hardness Tool Steels |
| title_fullStr | Retained Austenite Control for the Soft Machining of High-Hardness Tool Steels |
| title_full_unstemmed | Retained Austenite Control for the Soft Machining of High-Hardness Tool Steels |
| title_short | Retained Austenite Control for the Soft Machining of High-Hardness Tool Steels |
| title_sort | retained austenite control for the soft machining of high hardness tool steels |
| topic | retained austenite laser cladding cryogenic treatment tool steel hardness |
| url | http://www.mdpi.com/2075-4701/8/7/564 |
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