Rolling method for steel for non-quenched-and-tempered connecting rod of engine and manufacturing method of forge pieces

Abstract

The invention discloses a rolling method for steel for a non-quenched-and-tempered connecting rod of an engine and a manufacturing method of forge pieces. A continuous casting billet is formed throughtwice heating, a high-temperature diffusion heating process is adopted in first heating, the total heating time is controlled to be 240-360 min, segregation elements in the material are fully diffused in the heating mode that the heating time of a high-temperature section is not shorter than 100 min, a rolling-controlled and cooling-controlled process is adopted in the second heating rolling process, and the manufacturing method of the forge pieces comprises the steps of blanking, induction heating and controlled cooling, wherein by limiting the conditions that the induction heating temperature is 1200-1230 DEG C, the cooling speed on an air cooling line is controlled to be 3-4.5 DEG C/S, the temperature of an air cooling line under a forging blank is controlled to be 580-620 DEG C, the grain size of the connecting rod is effectively refined, the strength, toughness and plasticity of the material are improved, abnormal texture is prevented, surface scratches and other defects are prevented, the ferrite proportion is reduced, and good economic benefits and environmental benefits are obtained.

Description

technical field [0001] The invention relates to the technical field of production of non-quenched and tempered connecting rods of engines, in particular to a method for manufacturing non-quenched and tempered connecting rods of engines, steel and forgings thereof. Specifically, it is a controlled rolling and controlled cooling process of steel for non-quenched and tempered connecting rods of engines and a controlled heating and controlled cooling process of forgings. Background technique [0002] The engine is the most important part of the car, and the connecting rod is a key part inside the engine. The generated gas exerts an alternating load on the connecting rod. At the same time, the impact force generated by fuel combustion is transmitted to the connecting rod through the piston. The connecting rod converts the linear reciprocating motion of the piston into the rotational motion of the crankshaft, and outputs power through the crankshaft. It can be seen from the worki...

AI Technical Summary

Problems solved by technology

[0004] Although the overall performance of 46MnVS6 is better than that of C70S6 high-carbon non-quenched and tempered steel, it has many elements that are prone to segregation (such as C, P, S, Mn, etc.), and the quality problems of uneven structure are prone to occur in the subsequent rolling and forging processes. It affects the expansion performance of the connecting rod, so it is more difficult to manufacture. With in-depth research, the ultrasonic flaw detection pass rate and low-magnification structure produced by the 46MnVS6 rolling process are difficult to further improve. Therefore, how to improve the above performance and at the same time ensure that the connecting rod billet Uniform structure, surface decarburization and surface defects can also be effectively controlled comprehensive performance, which has also become a major difficulty in the industry. In addition, the ferrite in the current production of 46MnVS6 structure can only reach 10 -15%, it is difficult to further reduce, how to obtain a 46MnVS6 production process, not only can solve the above problems, but also control the ferrite ratio at a very low ratio, this is the technical problem to be solved by this application

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