A rolling method of steel for non-quenched and tempered connecting rod of an engine and a manufacturing method of a forging

Abstract

The invention discloses a rolling method of steel for non-quenched and tempered connecting rods of engines and a manufacturing method of forgings. The continuous casting slab is made into material through two fires, one of which adopts high-temperature diffusion heating process, and the total heating time is controlled from 240 to 360 minutes, and the heating time of the high-temperature section is not less than 100 minutes to fully diffuse the segregated elements in the material. The controlled rolling and controlled cooling process is adopted during fire rolling. The forging method includes blanking, induction heating, and controlled cooling. The induction heating temperature is 1200-1230°C, and the cooling rate on the air-cooled line is controlled to be 3-4.5°C / S. Controlling the temperature of the lower air-cooling line of the forging blank at 580-620°C effectively refines the grain size of the connecting rod, improves the strength, toughness and plasticity of the material, prevents abnormal structures, and prevents defects such as surface scratches produce, reduce the proportion of ferrite, and obtain good economic and environmental benefits.

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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