Heat treatment system used for producing ultrahigh strength steel

Abstract

The invention discloses a heat treatment system used for producing ultrahigh strength steel. The technological layout of the system is that: (1) a quenching machine is arranged behind a roller-hearth quenching furnace; a long transporting roll table with a length of 30 to 35m is arranged behind the quenching machine; and an open-fire low-temperature roller-hearth tempering furnace is arranged behind the transporting roll table; (2) a steel plate is heated in the roller-hearth quenching furnace, and the temperature is maintained; (3) the quenching machine is configured as in a quenching mode; and the technological speed of the quenching machine is controlled at 5 to 6m / min according to the thickness of the steel plate, wherein the thickness of the steel plate is 8 to 60mm. (4) the steel plate is heated; the temperature is maintained; the steel is fetched and quenched; the quenched steel plate is places on the transporting roll table for self-tempering, wherein the self-tempering temperature is Ms to Mf (the specific temperature is determined according to the steel type); (5) when self-tempering is finished, the steel plate is delivered to the tempering furnace in time with high speed for carrying out carbon distribution, wherein the temperature is maintained; the steel plate is delivered forward according to a preset technological speed; (6) when a carbon distribution time is satisfied, the steel plate is fetched from the furnace in time to be air-cooled; (7) when the steel plate is processed through a Q+P process, the steel plate can be transported to another tempering furnace for tempering when necessary.

Description

Technical field [0001] The invention belongs to the steelmaking technology, in particular to a heat treatment system for producing ultra-high-strength steel. Background technique [0002] The heat treatment equipment configuration of wide and thick plate factory generally includes normalizing furnace, quenching furnace and quenching machine, that is, a normalizing production line and a quenching and tempering production line, which complete the steel plate normalizing, quenching and tempering, tempering, normalizing + tempering process. In the typical process layout, the quenching and tempering process of the steel plate is as follows: steel plate shot blasting treatment; steel plate is loaded into the quenching furnace for heating; steel plate is quenched out of the furnace; quenched steel plate is collected and stacked offline; ;The quenched steel plate is loaded to be tempered; the steel plate is heated and tempered in the tempering furnace; the tempered steel plate is ai...

AI Technical Summary

Problems solved by technology

[0004] However, as academician Xu Zuyao, a famous material scientist, pointed out, there are still the following problems in the production and development of Q+P+T steel: the purity and homogeneity of high-strength steel must be highly valued in smelting, continuous casting and rolling processing. ; Improving product strength and reducing weight still needs to be attempted by mechanical designers; The processing and heat treatment equipment, process and operation of high-strength steel, especially ultra-high-strength steel with a strength greater than 2000MPa, have yet to be resolved

The disadvantages of this invention: the temperature required for carbon distribution is low, and when the tempering temperature reaches 560-780°C, martensite and retained austenite will inevitably decompose; during induction heating, eddy current effect heats up at the lattice defects of the steel plate, The local temperature is high, which cannot meet the process requirements of carbon distribution

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