Method for surface quenching treatment of 10B21 casting blank and compact-surface 10B21 casting blank obtained by same

A technology of surface quenching and casting slabs, which is applied in the field of surface quenching 10B21 slabs and surface dense 10B21 slabs. It can solve the problems of reducing production efficiency, affecting production rhythm, and increasing production costs, so as to suppress the occurrence of surface cracks and reduce The surface is prone to wear and tear, and the effect of improving the service life

Active Publication Date: 2021-06-18
UNIV OF SCI & TECH BEIJING
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  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, there are two main problems in the method of suppressing the surface cracks of 10B21 slab by adding alloys during hot delivery: one is to increase the production cost; the other is not easy to control, and the composition change may be delayed; There are also two main problems in the method of suppressing surface cracks during the hot delivery of 10B21 slabs: one is that the production efficiency is reduced, and the other is that it affects the production rhythm on site, and it is easy to cause tension in the storage space
[0005] Chinese patent application CN103924248A discloses a carbonitriding quenching process for automotive seat adjuster parts. The embryo material used is 10B21, which adopts the heat treatment method of surface carbonitriding and low temperature tempering, which greatly improves the regulator Surface strength and wear resistance of components; although the patent application also quenches 10B21, the quenching process is inefficient, and the patent application is mainly for the production of components with high surface strength, and its main emphasis is on carbon nitrogen co-infiltration
[0006] Although surface quenching technology is a common technology for heat treatment of steel, for 10B21 slabs, there has been no suitable surface quenching process for surface quenching of 10B21 slabs, so as to ensure the proper hardening depth of slabs and reasonable control. The structure type of the surface of the slab, so as to effectively suppress the generation of surface cracks during the hot delivery of the slab

Method used

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  • Method for surface quenching treatment of 10B21 casting blank and compact-surface 10B21 casting blank obtained by same
  • Method for surface quenching treatment of 10B21 casting blank and compact-surface 10B21 casting blank obtained by same
  • Method for surface quenching treatment of 10B21 casting blank and compact-surface 10B21 casting blank obtained by same

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Effect test

Embodiment 1

[0081] The production process of 10B21 slab is: molten iron pretreatment → top-bottom combined blowing converter smelting → deoxidation alloying → LF refining → continuous casting.

[0082] Hot metal pretreatment: control the composition of the hot metal after pretreatment Si≤0.70%, P≤0.11%.

[0083] Top-bottom combined blowing converter smelting: adopt the method of high-drawing supplementary blowing to control the composition of molten steel in converter tapping: 0.05~0.09%, P≤0.012%.

[0084] Deoxidation alloying: 11kg / t of high-carbon ferromanganese is added to the ladle when the converter is tapping (that is, 11kg of high-carbon ferromanganese is added to the molten steel for each ton of converter tapping), and 1.5kg / t of high-carbon ferrochrome (that is, per ton Add 1.5kg of high-carbon ferrochromium to the converter tapping molten steel), an appropriate amount of low-nitrogen recarburizer (graphene recarburizer with a nitrogen content below 500ppm), and the amount of allo...

Embodiment 2

[0095] The production process of 10B21 slab is: molten iron pretreatment → top-bottom combined blowing converter smelting → deoxidation alloying → LF refining → continuous casting.

[0096] Hot metal pretreatment: control the composition of the hot metal after pretreatment Si≤0.70%, P≤0.11%.

[0097] Top-bottom combined blowing converter smelting: adopt the method of high-drawing supplementary blowing to control the composition of molten steel in converter tapping: 0.05~0.09%, P≤0.012%.

[0098] Deoxidation alloying: 11kg / t of high-carbon ferromanganese is added to the ladle when the converter is tapping (that is, 11kg of high-carbon ferromanganese is added to the molten steel for each ton of converter tapping), and 1.5kg / t of high-carbon ferrochrome (that is, per ton Add 1.5kg of high-carbon ferrochromium to the converter tapping molten steel), an appropriate amount of low-nitrogen recarburizer (graphitized recarburizer with a nitrogen content below 500ppm), and the amount of...

Embodiment 3

[0109] The production process of 10B21 slab is: molten iron pretreatment → top-bottom combined blowing converter smelting → deoxidation alloying → LF refining → continuous casting.

[0110] Hot metal pretreatment: control the composition of the hot metal after pretreatment Si≤0.70%, P≤0.11%.

[0111] Top-bottom combined blowing converter smelting: adopt the method of high-drawing supplementary blowing to control the composition of molten steel in converter tapping: 0.05~0.09%, P≤0.012%.

[0112] Deoxidation alloying: 11kg / t of high-carbon ferromanganese is added to the ladle when the converter is tapping (that is, 11kg of high-carbon ferromanganese is added to the molten steel for each ton of converter tapping), and 1.5kg / t of high-carbon ferrochrome (that is, per ton Add 1.5kg of high-carbon ferrochromium to the converter tapping molten steel), an appropriate amount of low-nitrogen recarburizer (graphitized recarburizer with a nitrogen content below 500ppm), and the amount of...

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Abstract

The invention relates to a method for surface quenching treatment of a 10B21 casting blank and the compact-surface 10B21 casting blank obtained by the same. The method comprises the following steps that a 10B21 casting blank is provided; the casting blank is subjected to surface quenching, and a quenched casting blank is obtained; tempering is conducted through the core part waste heat of the quenched casting blank, and the 10B21 casting blank with the compact surface is obtained; the quenching time is 40-100s, the initial temperature is 808-857 DEG C, the final temperature is 211-667 DEG C, the through quenching depth is 8-10mm, and the tempering highest point temperature is 535-695 DEG C; and in the depth direction from the surface of the casting blank to a core part, the organization structure of the 10B21 casting blank with the compact surface is gradually converted from tempered sorbite as the main part to bainite as the main part, and then is gradually converted into ferrite and pearlite as the main part. According to the method, effective control over the surface structure type of the 10B21 casting blank is achieved through the surface quenching technology, and therefore, generation of surface cracks in the casting blank hot delivery process is effectively restrained.

Description

technical field [0001] The invention belongs to the technical field of steel production, and relates to a heat treatment surface quenching process for steel, in particular to a method for surface quenching treatment of a 10B21 billet and a 10B21 billet with a dense surface obtained therefrom. Background technique [0002] 10B21 is a cold heading steel wire rod, which is mainly used to manufacture bolts, nuts and other parts. Its composition is stable and the market demand is large. It is widely used in construction engineering, machinery manufacturing, auto parts and other fields. Due to the fact that aluminum nitride, boron nitride and other precipitates hinder the movement of grain boundaries in the steel during hot deformation, resulting in stress, the surface of 10B21 billet is prone to surface cracks during hot delivery, which seriously affects the processing performance, resulting in 10B21 billet When processed into products, it is easy to produce unqualified products,...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C21D1/18C22C38/02C22C38/04C22C38/28C22C38/32C22C38/06
CPCC21D1/18C21D2211/005C21D2211/009C22C38/02C22C38/04C22C38/06C22C38/28C22C38/32
Inventor 刘威杨树峰宋朝琦陈永峰左小坦李京社赵朋
Owner UNIV OF SCI & TECH BEIJING
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