Quick-cooling device for reducing surface crack generation rate of hot-feeding casting blank

A technology of surface crack and generation rate, applied in the field of iron and steel metallurgy, can solve the problems of weakened grain boundary strength, thermal stress crack, insufficient suppression and other problems

Pending Publication Date: 2020-01-17
SHANDONG IRON & STEEL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0010] However, when only one transition from austenite to ferrite + pearlite occurs, the grain refinement is not obvious. When the billet is reheated in the heating furnace and is in the Ar1→Ar3 two-phase region, most The grain size is still above 50um, and the grain size of this size is not enough to suppress the generation of cracks on the surface of the hot-send slab with high crack sensitivity. The high-crack-sensitivity hot-send slab refers to the Nb, The sum of the mass concentrations of V and Ti is greater than 0.08%, and the high concentration of microalloying elements will seriously weaken the grain boundary strength
[0011] In the process of intensive cooling of the slab, large thermal stress will be generated. If the cooling is not uniform, thermal stress cracks will be caused. There is no report on how to improve the uniformity of cooling in the process of rapid cooling of the slab.

Method used

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  • Quick-cooling device for reducing surface crack generation rate of hot-feeding casting blank
  • Quick-cooling device for reducing surface crack generation rate of hot-feeding casting blank
  • Quick-cooling device for reducing surface crack generation rate of hot-feeding casting blank

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Experimental program
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Effect test

Embodiment 1

[0069] Such as figure 2 Shown, a kind of fast cooling device that reduces the generation rate of cracks on the surface of the hot casting slab, the fast cooling device includes a round of fast cooling device, and the fast cooling device also includes two rounds of fast cooling device and steam removal cover 7;

[0070] The two-wheel fast cooling device comprises a conveying roller table 2, several rows of upper cooling nozzle groups 3 are set above the conveying roller table 2, and several rows of lower cooling nozzle groups 1 are arranged below the conveying roller table 2. Pyrometer 8 is set respectively at the inlet and outlet of the

[0071] 2-3 rows of upper cooling nozzle groups 3 and lower cooling nozzle groups 1 are evenly arranged between every two conveying rollers of the conveying roller table 2;

[0072] The steam removal cover 7 communicates with the steam collection device 10 through the steam passage 5; the steam removal cover 7 is covered on the two-wheel rap...

Embodiment 2

[0083] Since the 700Mpa grade automobile beam steel needs to add more than 0.1% titanium and more than 0.04% niobium, the content of microalloying elements is high, and the high content of microalloying elements is easy to segregate at the ferrite grain boundary, which increases the cracks on the surface of the slab Sensitivity, the 700Mpa grade automobile frame steel hot casting slab has a high crack occurrence rate during rolling, reaching more than 10%. In order to reduce the 700Mpa automobile frame steel hot delivery slab surface crack generation rate, the following methods are adopted, mainly Including the following two aspects.

[0084] 1. In the continuous casting process, the surface of the slab is subjected to two rounds of rapid cooling by means of a rapid cooling device to refine the grain size of the slab surface, so as to improve the plasticity of the slab surface, including the following technical solutions:

[0085] A: If Figure 5 As shown, a large-flow coolin...

Embodiment 3

[0104] Because the Q690 grade high-strength steel needs to add a large amount of microalloying elements to increase the strength, the sum of the added Nb, V, and Ti mass is greater than 0.1%, and the content of microalloying elements is high. Polymerization, which improves the crack sensitivity of the slab surface, the crack occurrence rate of Q690 level high-strength steel hot-delivery slab is high during rolling, reaching more than 10%. The following methods are proposed, mainly including the following two aspects.

[0105] 1. During the continuous casting process, two rounds of rapid cooling are performed on the surface of the slab to refine the grain size of the slab surface, so as to improve the plasticity of the slab surface, including the following technical solutions:

[0106] A: Arrange large-flow cooling nozzles 13 in the horizontal section adjacent to the straightening section. The horizontal section is 3m long, and a row of large-flow cooling water nozzles 13 is ar...

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Abstract

The invention discloses a quick-cooling device for reducing the surface crack generation rate of a hot-feeding casting blank. The quick-cooling device comprises a first round quick-cooling device, andthe quick-cooling device further comprises a second round quick-cooling device and a vapor-removing cover; the second round quick-cooling device comprises a transport roller way, a plurality of rowsof upper cooling nozzle sets are arranged above the transport roller way, a plurality of rows of lower cooling nozzle sets are arranged below the transport roller way, and high temperature meters arearranged at an inlet and an outlet of the transport roller way correspondingly; 2-3 rows of upper cooling nozzle sets and lower cooling nozzle sets are uniformly arranged between every two conveying rollers of the transport roller way; the vapor-removing cover is in communication with a vapor collection device through a vapor channel; and the vapor-removing cover covers the second round quick-cooling device. The quick-cooling device can be used for refining the grain size of the surface of the casting blank, and after two rounds of quick cooling, the average grain size of the surface of the casting blank can reach 25 um or below.

Description

technical field [0001] The invention belongs to the technical field of iron and steel metallurgy, in particular, the invention relates to a rapid cooling device for reducing the generation rate of cracks on the surface of a hot casting slab. Background technique [0002] Billet hot delivery technology is a technology that quickly sends the hot billet produced by continuous casting to the steel rolling area for rolling. It can use the sensible heat of the red hot billet to save energy consumption. However, since the surface temperature of the hot cast slab is about 600-750°C when it is sent to the steel rolling area, the transformation of the austenite structure in the cast slab to the ferrite + pearlite structure is not complete at this temperature, and a part of the austenite remains When the slab is reheated in the heating furnace, the part of the austenite structure gradually swallows the surrounding ferrite grains to form coarse austenite grains, and the ferrite grains a...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B22D11/124B22D11/22
CPCB22D11/124B22D11/1246B22D11/22
Inventor 刘洪银陈永生王庆臣高岩刘迪陈显著魏兵兵朱宝晶杜彧魏泽华
Owner SHANDONG IRON & STEEL CO LTD
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