Direct quenching device for medium plate and quenching process thereof

Abstract

The invention provides a direct quenching device for a medium plate and a quenching process thereof. The device comprises a high-level water tank, a water quantity distributor, upper quenching coolers, upper accelerating coolers, upper fine-tuning coolers, lower quenching coolers, lower accelerating coolers, lower fine-tuning coolers, edge shielding devices, side spraying devices and a purging device. The quenching method comprises the following steps: carrying out controlled rolling, and controlling the finished rolling temperature at 780-850 DEG C; calculating the speed of a roller way, the group number of the coolers to be started, the water quantity of the coolers and the edge shielding quantity according to the plate thickness and the steel grade by utilizing a computer, and then transferring the plate to a controlled cooling area according to a predetermined speed; and starting the coolers and the corresponding side spraying devices according to the position sequence of the plate, wherein, the finished cooling temperature range is 150-450 DEG C. The direct quenching device has the characteristics of low fabrication cost, and fast and uniform cooling speed, and can stably produce the flat quenching plate with the quenching thickness of 9-60mm, and is simple and convenient in maintenance; and compared with the traditional out-line quenching method, the quenching process provided by the invention has the characteristics of short process flow and less energy consumption.

Description

technical field [0001] The invention belongs to the field of iron and steel production technology, in particular to a device and technology for direct quenching of medium-thick steel plates. Background technique [0002] Direct quenching means that when the steel is in the austenite structure at the end of hot rolling, the structure of the rolled piece will be transformed into martensite and bainite through rapid cooling treatment, and the grains will be refined to improve the toughness of the material. Compared with the reheating quenching process, the direct quenching process omits the reheating austenitization process, saves energy and simplifies the process. It should be pointed out that the direct quenching here is no longer the so-called quenching in the traditional heat treatment process, it is the online application of the sub-quenching and tempering process. [0003] In the follow-up heat treatment process of controlled rolling and controlled cooling, domestic high...

AI Technical Summary

Problems solved by technology

[0003] In the follow-up heat treatment process of controlled rolling and controlled cooling, domestic high-strength steel is generally produced by reheating quenching + tempering (that is, quenching and tempering treatment). This production process not only increases equipment investment, but also has many procedures and a long production cycle. At the same time, the alloying cost and production process cost of steel are greatly increased, which greatly restricts the improvement of economic benefits.

There are also domestic reports on the production of high-strength steel plates using non-quenched and tempered processes. For example, the Chinese patent application (application number 2006100519362) in 2006 disclosed "1100Mpa non-quenched and tempered high-strength steel and its production method". After rolling, a cold rolling process with a large reduction is required, the process is complicated and the investment is huge

Another example is the 2008 Chinese patent application (application number 200810013604.4) which announced "a direct quenching production process for high-strength and tough thick steel plates". , it is difficult to solve the problem of flatness caused by uneven cooling for thinner steel plates, and the composition of the steel plates is strict, so it is difficult to popularize in the field of alloy steel production

In 2009, the Chinese patent application (Application No. 2008101960402) disclosed the "Process for On-line Quenching of Steckel Mill to Produce High Stress and Tempering Steel". This patent is only suitable for on-line quenching of Steckel Mill to produce quenched and tempered plates with a thickness of 12mm-35mm, and the arrangement of process equipment is limited. It is used in the coil production line, and the cooling capacity of the laminar cooling device is limited, so it is difficult to realize online quenching for steel plates with a thickness greater than 35mm

Another example is the 2009 Chinese patent application (application number 200910091825.8) "a direct quenching process suitable for high-strength and tough steel plates of different thicknesses". This patent uses a laminar flow cooling device to achieve online quenching. The water volume is fixed and cannot be adjusted freely. Each set of headers only contains a set of upper and lower nozzles. The water flow density is low, the impact area is small, and the cooling capacity is weak. It is difficult to achieve a large cooling rate. It has certain limitations for on-line quenching to produce high-strength steel.

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