An improved 9ni material suitable for large cross-section parts and its preparation method

Abstract

The invention belongs to the field of forging and particularly discloses an improved 9Ni material applicable to a large-section component and a preparation method thereof. By adopting the material andthe preparation method thereof, the problem that when a traditional 9Ni material is applied to the large-section component, the low-temperature toughness is poor is solved. According to the improved9Ni material and the preparation method thereof, in respect of improvement on the fracture toughness and hardenability, the contents of the elements including C, Mn, Si, Mo, Al, RE and the like in the9Ni material are optimized and controlled. Heat treatment simulation is performed on the quenching and tempering process of traditional 9Ni steel applied to a large forging, a heat treatment simulation furnace is utilized for performing physical simulation on the surface, the 1 / 2 R position and the center, as the samples, of the large forging, and mechanical property evaluation is performed to illuminate microstructure and property distribution laws from the surface to the center area of the 9Ni steel shaft large forging. The 9Ni material with ingredients optimized is observed and analyzed under a microscope and a scanning electron microscope, sample microstructures of the surface, 1 / 2 R position of the section and the center of the large forging are improved, and the mechanical propertyof the improved 9Ni material is greatly improved.

Description

technical field [0001] The invention belongs to the field of forging, and in particular relates to an improved 9Ni material suitable for large cross-section parts and a preparation method thereof. Background technique [0002] 9Ni steel is a steel for ultra-low temperature with a Ni content of about 9%. It has excellent low-temperature toughness, good weldability, and relatively low cost. It has become an important structural material for low-temperature equipment and containers at -196°C. Widely used in liquefied natural gas cryogenic storage tank plates, although it shows good mechanical properties in the above application cases, when the traditional 9Ni material is applied to large cross-section parts, its core will show problems such as poor low temperature toughness and uneven structure. And at present, there are very few applications in large cross-section parts in China. Therefore, the present invention is developed for the 9Ni material used in large-section componen...

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Problems solved by technology

[0003] The object of the present invention is to provide a kind of 9Ni material that is applicable to large cross-section parts and preparation method thereof, in order to solve the problems such as poor structure and mechanical property that traditional 9Ni material shows on large cross-section parts

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