High-performance steam cylinder cover for large low-speed diesel engine and manufacturing process

Abstract

The invention relates to a high-performance steam cylinder cover for a large low-speed diesel engine and a manufacturing process. According to the high-performance steam cylinder cover and the manufacturing process, after steam cylinder cover forge pieces are produced, the phenomena of segregation, loosening, uneven grain distribution and the like cannot occur inside, the performance difference in the same plane is extremely small, performance is stable, and the material utilization rate is high. The high-performance steam cylinder cover is prepared from, by mass percent, 0.17%-0.22% of C, 0.45% of Si or less, 0.95%-1.1% of Mn, 0.03% of P or less, 0.03% of S or less, 0.9%-1.1% of Cr, 0.4%-0.5% of Mo, 0.4% of Ni or less, 0.08%-0.12% of V and 0.005% of Nb or less. The high-performance steam cylinder cover has the beneficial effects that the workpiece structure is uneven, and internal stress is extremely small; production cost increase is effectively controlled; the subsequent workpiece cutting machining amount is small, and time and labor are saved during machine tool machining; and after ultrasonic testing, the internal grains are stable in state, and no coarse grain phenomenon exists.

Description

technical field [0001] The invention relates to a large-scale low-speed cylinder head forging that does not have segregation, porosity, and uneven grain distribution after the production is completed, and has very slight performance differences in the same plane, stable performance, and high material utilization. A high-performance cylinder head for a diesel engine and its manufacturing process belong to the field of cylinder head manufacturing. Background technique [0002] At present, domestic marine diesel engine manufacturers all use MAN's patented technical requirements to manufacture cylinder heads. Due to performance requirements, alloy steel forgings are mostly used. However, alloy steel forgings have poor plasticity and toughness. Phenomena such as segregation, porosity, and uneven grain distribution, after performance testing, lead to inconsistent indicators or great performance differences in the same plane, resulting in unstable performance. On the other hand, d...

AI Technical Summary

Problems solved by technology

[0004] 1. For upsetting the whole ingot, a large amount of reduction must be used. Although the grains inside the ingot are broken, it plays a role in refining, but for low-carbon alloy steel, its plasticity is relatively poor, and segregation may still exist inside , or the organization is uneven, and there will be a large internal stress;

[0005] 2. After the wrong riser is upset on the large flat anvil, the amount of side extrusion is not easy to control, so it is necessary to increase the weight of the blank when blanking, resulting in an increase in production costs;

[0006] 3. After spheronizing, the cylinder head rough-machined finished product size is divided into different diameters, and the subsequent workpiece cutting process is very large, and the machine tool processing is time-consuming and laborious;

[0007] 4. After ultrasonic testing, the internal grain state is not stable enough, and there is a "coarse grain" phenomenon. This subsequent heat treatment process brings potential risks

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