CN1250752C - Non-quenched and tempered steel engine crankshaft tempering process - Google Patents

Abstract

The invention discloses a non-quenched and tempered steel engine crankshaft tempering process. The tempering temperature is set at 310° C., and a plate of parts is pushed every 12 minutes; the tempering time is 3 hours. After this tempering process, the surface hardness level of the crankshaft is equivalent to that of the original imported crankshaft, which not only reduces the deformation and repair ratio of the crankshaft, but also obtains a hardness result that meets the requirements, which meets the process requirements and use requirements. It ensures the smooth progress of the localization of imported engine crankshafts and the process of the overall localization rate of imported engines, and obtains considerable economic benefits.

Description

Non-quenched and tempered steel engine crankshaft tempering process

Technical field: the invention belongs to the field of heat treatment, and relates to a non-quenched and tempered steel engine crankshaft tempering process.

Background technology: The initial tempering process in the localization of imported engine crankshafts is: tempering temperature 250 ° C, pushing a plate of parts every 12 minutes, and tempering time is 2 hours. The surface hardness of the crankshaft after this tempering process is mostly between HRC52-54, which does not meet the requirements of HRC45-50 on the surface hardness of the product drawing. Moreover, when the tempering temperature increases during tempering, the deformation of the crankshaft increases, and the repair ratio also increases.

Summary of the invention: In order to solve the problem that the surface hardness of the existing crankshaft tempering process cannot meet the requirements, the present invention proposes a non-quenched and tempered steel engine crankshaft tempering process. The tempering temperature is set at 310°C, and one plate is pushed every 12 minutes. Parts, each plate of parts does not interfere with each other; tempering time is 3h.

After this tempering process, the surface hardness level of the crankshaft is equivalent to that of the original imported crankshaft, which not only reduces the deformation and repair ratio of the crankshaft, but also obtains a hardness result that meets the requirements, which meets the process requirements and use requirements. It ensures the smooth progress of the localization of imported engine crankshafts and the process of the overall localization rate of imported engines, and obtains considerable economic benefits.

Specific implementation method: adopt the non-quenched and tempered steel engine crankshaft tempering process of the present invention, set the tempering temperature as 310°C, push a set of parts every 12 minutes, and ensure that each set of parts is 4 pieces, and the crankshaft parts must not interact with each other Interference; tempering time is 3h. After tempering through this process, the hardness of the parts has reached the hardness level of imported original parts, and meets the requirements of the drawings. In addition, although the tempering temperature is higher than that of the old process, due to the adoption of a new method of parts placement, the swing of the crankshaft after tempering is very small, so that it is controlled within the Cummins standard. Different placement methods of parts under different tempering temperatures were used to test different tempering processes of non-quenched and tempered steel crankshafts after intermediate frequency quenching.

Table 1 Comparison data of swing difference of different tempering processes after intermediate frequency quenching of non-quenched and tempered steel crankshaft tempering temperature 250°C 310°C Number of inspection pieces 34 52 Swing <0.21 0 0 Swing difference≤0.21＞0.18 1 0 Swing difference≤0.18＞0.15 1 0 Swing difference≤0.15＞0.12 8 1 Swing difference≤0.12＞0.09 9 1 Swing difference≤0.09＞0.06 13 5 Swing difference≤0.06＞0.03 2 29 Pendulum ≤0.03 0 17 Swing mean 0.10 swing maximum 0.20 variance 0.06 Number of out-of-tolerance pieces 2 0 Over-poor rate 5.9% 0

It can be seen from the above table that the surface hardness level of the crankshaft after this tempering process is equivalent to the hardness level of the original imported crankshaft, which not only reduces the deformation of the crankshaft and the repair ratio, but also obtains a hardness result that meets the requirements of the drawing. It ensures the smooth progress of the localization of imported engine crankshafts, and meets the process requirements and use requirements. At the same time, the process of the overall localization rate of imported engines has been accelerated, and considerable economic benefits have been obtained.

Claims (3)

1. A non-quenched and tempered steel engine crankshaft tempering process, the tempering temperature is set at 310°C, a plate of parts is pushed every 12 minutes, and the tempering time is 3 hours. 2. The non-quenched and tempered steel engine crankshaft tempering process according to claim 1, characterized in that: each disc part does not interfere with each other. 3. The non-quenched and tempered steel engine crankshaft tempering process according to claim 2, characterized in that: each disc part is four pieces.