A kind of continuous furnace high temperature carburizing method and carburizing cr-mo steel parts

Abstract

The invention relates to a Cr-Mo steel used for high-temperature carburizing, a carburizing method thereof, and carburized parts. The Cr-Mo steel used for high-temperature carburizing has the following chemical composition in terms of weight percentage: C 0.13-0.25 , Si≤0.25, Mn 0.55~0.90, P≤0.035, S 0.020~0.040, Cr 0.85~1.25, Al 0.017~0.037, Ti 0.008~0.015, Nb 0.040~0.060, O≤15ppm, N 120ppm~170ppm, Ni 0.010 ~0.030, Cu 0.10~0.20, Mo≤0.06, V≤0.04, and the rest are Fe and unavoidable impurities. The Cr-Mo steel for high-temperature carburizing provided by the present invention can meet the requirement that when the carburizing temperature is ≥980°C, the grain size of the parts is not thicker than grade 7; the continuous furnace high-temperature carburizing method provided by the present invention adopts three-stage preheating and low Carbon potential diffusion high-temperature carburizing process realizes high-efficiency carburizing of parts. Under the premise of ensuring the carburized layer depth of parts is 1.1-1.6mm, the carburizing heat treatment cycle can be shortened to 13.2h, and the carburizing time can be shortened to 7.2h. Compared with 920℃~930℃, the carburizing efficiency is increased by 25%~30%.

Description

technical field [0001] The invention belongs to the field of auto parts industry and metallurgy technology. The invention relates to a Cr-Mo steel used for high-temperature carburizing, a carburizing method, and carburizing parts. Background technique [0002] Cr-Mo series carburizing steel for domestic heavy-duty gearbox parts, the national standard GB / T5216 specifies the material alloy element mass percentage (%): C0.17~0.23, Si0.17~0.37, Mn0.55~0.90, Cr0.85 ~1.25, Mo0.15~0.25 Residual elements: P≤0.035, S≤0.035, Cu≤0.25, Ni≤0.30, austenite grain size not coarser than grade 5. [0003] The Cr-Mo series carburizing steel specified in the standard CGMA001~1 formulated by the China Gear Professional Association specifies the material alloy element mass percentage (%): C0.18~0.23, Si0.17~0.37, Mn0.40~0.70, Cr0.80~1.10 , Mo0.15~0.25Al0.02~0.05 Residual elements: P≤0.030, SS≤0.025, Cu≤0.30, Ni≤0.30, the austenite grain size is not coarser than grade 5. [0004] The carburizin...

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Problems solved by technology

[0005] In order to solve the problem that the existing Cr-Mo carburizing steel cannot meet the high-temperature carburizing requirements above 980°C, the present invention provides a Cr-Mo steel for high-temperature carburizing, its carburizing method, and carburizing parts

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