Steel for 600MPa-grade high-strength engineering machines and production method thereof

Abstract

The invention relates to steel for 600MPa-grade high-strength engineering machines and a production method thereof, belonging to the technical field of steel for the engineering machines. The steel comprises the following chemical components by weight percent: C: 0.06-0.09%, Si: 0.15-0.25%, Mn: 1.4-1.6%, P: not more than 0.020%, S: not more than 0.010%, Alt: 0.020-0.060%, Nb: 0.040-0.060%, Ti: 0.09-0.12% and the balance of Fe and inevitable impurities. The steel has no expensive elements such as Mo, V and the like, 2 frames are adopted for rough rolling, and 6 frames are used for finish rolling, thereby carrying out controlled rolling; and 20-group laminar cooling is used for strictly controlling the cooling, and internal stress is eliminated by adopting a temperature-holding pit for slow cooling after being offline, thereby being capable of stably producing a hot rolled coil with excellent toughness and low cost, which has the thickness being 5-16mm, the yield strength being more than 600MPa, the V type Charpy impact energy at -20 DEG C being not less than 40J and is applicable to the field of the engineering machines and the like.

Description

technical field [0001] The invention belongs to the technical field of steel for engineering machinery, and in particular relates to a 600MPa high-strength steel for engineering machinery and a production method thereof. Background technique [0002] High-strength engineering machinery steel is a low-alloy high-strength steel based on C-Mn steel and added with microalloying elements such as Mo, Nb, V, and Ti. At present, high-strength steel plates are widely used in the construction machinery industry and coal mining machinery industry, and the required thickness is mainly 4-80mm. Among them, steel plates with a thickness below 20mm are mainly coiled flat products, and most of them are used in the construction machinery industry. It is used to manufacture crane arms, frames, etc.; steel plates with a thickness of more than 20mm are mainly medium-thick plate products, and most of them are used in the coal mining machinery industry. Since hot-rolled coils do not have the same...

AI Technical Summary

Problems solved by technology

Since hot-rolled coils do not have the same strong control and cooling means as medium and thick plates, more alloy elements often need to be added, which increases the cost, and the coils need to be flattened during use, and the residual stress has a great influence on the shape of the plate. Minimize or eliminate the influence of residual stress, and the coils are mostly flattened and heat-treated during the production process, which also increases the cost

Only a few companies in China, such as Baosteel, Anshan Iron and Steel, and Wuhan Iron and Steel, produce 600-grade high-strength steel plates, most of which are added with precious metals such as Mo and V, and are produced by controlled rolling, controlled cooling and heating. The process is complicated and the cost is high.

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