Variable temperature martensite local strengthening austenite low manganese steel hammer head material and preparation process thereof

Abstract

The invention relates to a variable temperature martensite locally strengthened austenite manganese steel hammer head material and a preparation technology thereof, wherein a substrate of the material is a metastable austenite with a thinned structure, good toughness and improved work hardening capacity; a strengthened region is provided with a deep cooling martensite with high initial hardness and a small number of metastable martensites; and an intermediate transition region is provided with a mixed structure of the deep cooling martensites and the austenites with gradually changed gradient. The preparation technology comprises the following technological steps: a) design of the compositions of the substrate of manganese steel of metastable austenites; b) modification in a ladle before a furnace; c) direct water toughening after solidification; and d) acquisition of a surface layer or a local martensite transformation gradient strengthened layer. The material is characterized in that the structure of the strengthened layer is the variable temperature martensites (M) with high hardness and a small number of the metastable austenites (A); other parts are provided with the austenites with high toughness; and an intermediate transition layer is provided with a mixed structure of the Ms and the As with gradually changed gradient. Moreover, the preparation technology integrates design of the compositions of the manganese steel of the metastable austenites, the energy-saving heat treatment technology and the short-time local temperature variation treatment technology.

Description

technical field [0001] The invention relates to an austenitic low-manganese steel hammer head material and a preparation process thereof, which are used in various industrial departments under abrasive wear conditions. Background technique [0002] Austenitic high manganese steel (13% Mn) has been the most widely used important wear-resistant material since it came out in 1882 for 126 years. It is characterized by good toughness but low original hardness, and it shows good wear resistance only when it is subjected to strong impact and the surface layer is hardened, so it is more suitable for use under strong impact conditions; while for most other working conditions In this case, it appears that the toughness is sufficient but the hardness is insufficient, and the initial wear is serious, especially in the medium and low impact abrasive wear conditions, which are not wear-resistant due to insufficient work hardening. In order to improve the initial hardness of high manganes...

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Problems solved by technology

But at the same time, it also brings some difficult problems: because it is added in the smelting process, the burning loss of Ti is serious, the melt viscosity is high, the fluidity is poor, and it is extremely difficult to fill the mold. Therefore, it is necessary to increase the melting temperature, which not only wastes energy but also further increases Ti. Burnout

The generated TiC grows for a long time and has coarse particles, which affects the strengthening effect and reduces the material performance; it can only be compounded as a whole, the cost is high, and the toughness reserve is insufficient, so it is difficult to realize engineering application in the near future

For example, in recent years, someone has introduced a certain amount of (Fe.Mn.Cr) into austenitic manganese steel. 3 C or TiC particle reinforcement phase, made of particle reinforced steel matrix composites, but the effect is not good

When the volume fraction of the reinforcement phase is low, the hardness increases little, and the soft austenite is not enough to support the hard TiC, so the wear resistance does not improve much; when the volume fraction of the reinforcement phase is high, the hardness increases, but the toughness is lost Seriously, the safety of use cannot be guaranteed; and due to the introduction of the reinforcing phase, the process is complicated, the viscosity of molten steel is greatly increased, the fluidity is extremely poor, and the number of defects increases, making it difficult to cast

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