Nb and V microalloyed gear steel, preparation method, heat treatment method and carburizing treatment method thereof and carburized gear steel

A heat treatment method and micro-alloying technology, applied in the field of gear steel, can solve the problem of not being able to adapt to materials with high contact fatigue performance

CN113430461AActive Publication Date: 2021-09-24MAANSHAN IRON & STEEL CO LTD
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Patent Information

Authority / Receiving Office
CN · China
Current Assignee / Owner
Publication Date
2021-09-24

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Abstract

The invention discloses Nb and V microalloyed gear steel, a preparation method, heat treatment method and carburizing treatment method thereof and carburized gear steel. Nb and V microalloying is adopted, and the Nb and V microalloyed gear steel with a ferrite and pearlite structure is obtained. The production process comprises the steps of electric arc furnace smelting, LF refining, RH vacuum treatment, continuous casting, hot rolling and slow cooling. After the gear steel subjected to hot rolling and slow cooling is subjected to heat treatment, the Nb and V microalloyed gear steel with the tensile strength larger than or equal to 1465 MPa, the yield strength larger than or equal to 1340 MPa, the ductility larger than or equal to 14%, the percentage reduction of area larger than or equal to 50% and the impact energy KV2 larger than or equal to 95 J is obtained. The Nb and V microalloyed carburized gear steel with high contact fatigue performance is obtained after the gear steel subjected to hot rolling and slow cooling is subjected to carburizing treatment, and under the condition that the pressure stress is 4.0 GPa, the rated fatigue life L10 of the Nb and V microalloyed carburized gear steel is larger than or equal to 5 * 10 < 7 >, and the median fatigue life L50 of the Nb and V microalloyed carburized gear steel is larger than or equal to 8.2 * 10 < 7 >.
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Description

technical field

[0001] The invention belongs to the technical field of gear steel, and relates to a kind of Nb, V microalloyed gear steel and its preparation method, heat treatment method, carburizing treatment method and carburized gear steel, in particular to a kind of Nb, V microalloyed gear steel and Its preparation method, heat treatment method, carburizing treatment method and a kind of Nb, V micro-alloyed carburizing gear steel with high contact fatigue performance. Background technique

[0002] Gear steel is a key material with large consumption and high requirements in the field of special steel, and is widely used in machinery, transportation, energy and other fields. The performance requirements of gear steel not only affect the technical and economic indicators such as the service life of the equipment, but also affect the requirements of safety in use. The working environment of the gear is complex and harsh, and the main failure forms are the wear of the meshi...

Examples

Embodiment Construction

[0073]A kind of Nb, V micro-alloyed gear steel, comprising the following chemical composition in weight percentage: C: 0.15-0.19%, Si: 0.15-0.30%, Mn: 0.60-0.90%, Cr: 1.60-1.80%, Mo: 0.20 ~0.35%, Nb: 0.025~0.040%, Ni: 1.50~1.70%, Al: 0.020~0.040%, P: ≤0.010%, S: ≤0.010%, V: 0.05~0.20%, T.O: ≤10ppm, [ H]: ≤1.0ppm, [N]: 80-120ppm, Al / [N]: 2.5~5.0, the rest are Fe and unavoidable impurity elements, among them, Km=C+Mn / 6+(Cr+Mo+ V) / 5+(Ni+Cu) / 15+10Nb, and Km: 0.97-1.37.

[0074] It adopts the process of electric arc furnace smelting-LF refining-RH vacuum treatment-continuous casting-hot rolling-slow cooling, as follows:

[0075] The continuous casting slab is heated and kept at 1230-1280°C for ≥5 hours before round steel rolling. The rolling start temperature is 1120-1180°C and the final rolling temperature is 930-980°C. After rolling, it is cooled by a cooling bed to ≤650°C and slowly cooled , the slow cooling time is 48 hours, and the skin is ground and peeled after leaving the...