Non-quenched and tempered steel for high-strength high-low-temperature impact toughness lifting hook and production process thereof

Abstract

The invention discloses non-quenched and tempered steel for a high-strength high-low-temperature impact toughness lifting hook and a production process thereof. The steel comprises the following chemical components in percentage by weight, 0.25-0.40% of C, 0.20-0.40% of Si, 1.50-1.80%% of Mn, 0.07-0.10% of V, 0.020-0.040% of Al, smaller than or equal to 0.010% of P, smaller than or equal to 0.010%of S, smaller than or equal to 2 ppm of H, smaller than or equal to 10 ppm of O, and the balance Fe. By combining the group distribution ratio with a controlled rolling and controlled cooling process, the required performance level can be achieved without quenching and tempering treatment, and meanwhile, the low-temperature toughness at minus 20 DEG C meets the use requirement of the product, theproduction cost and the production difficulty are reduced, and the advantages of economy, energy conservation and environmental protection are achieved. The steel can be suitable for lifting hooks for buildings in cold areas.

Description

technical field [0001] The invention relates to the field of non-quenched and tempered steel for low temperature, in particular to a non-quenched and tempered steel for high-strength high-low temperature impact toughness hook and its production process. Background technique [0002] Hook is the most common spreader in hoisting machinery. Due to the direct action of external force, the stability of its quality directly affects the safety of equipment and people. The steel used for hooks must meet certain strength (yield strength, tensile strength) and toughness requirements according to its use environment, while in cold regions (such as -20°C), as the temperature decreases, the brittleness of steel gradually increases. It may lead to low temperature brittle fracture, so the low temperature impact toughness of steel is strictly required. [0003] Hooks are usually made of low-carbon alloy steel. In order to improve the low-temperature impact toughness of steel, suitable comp...

AI Technical Summary

Problems solved by technology

Although the strength of non-quenched and tempered steel can reach the level of quenched and tempered steel, its toughness is difficult to reach the level of quenched and tempered steel because the toughness of its structure is lower than that of tempered martensite, coupled with the precipitation strengthening of precipitates. limit its application

For example, in "Research on Low-temperature Impact Toughness of Microalloyed Non-quenched and Tempered Steel 35MnVN, Ding Houfu, etc.", there are problems such as insufficient impact toughness and plasticity of non-quenched and tempered steel

And the current research on the development and design of non-quenched and tempered steel products mainly focuses on the strength and toughness at room temperature. There are few studies on high and low temperature impact toughness, and there is no relevant research on the application of non-quenched and tempered steel in hooks.

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