JPS60118362A - Billet supporting device for continuous casting - Google Patents

Abstract

PURPOSE:To extend the service life of a titled supporting member by forming a coating layer consisting of a material having resistance to heat, wear and corrosion on the part of the supporting member in contact with a billet. CONSTITUTION:A coating layer made of a metal, alloy, cermet or ceramic having high resistance to heat, wear and corrosion is formed on at least a part, for example, cooling plate or the like of a billet supporting member made of a cast iron, steel for general structural purpose, copper or copper alloy in contact with a billet. The coating layer is a stainless steel consisting of Ni, Cr, Co, Ni-Cr, Co-Cr, Ni or Co contg. >=1 kind among W, Mo, Cr, P, etc. in the case of the metal and alloy. Said layer is WC or TiC alone or a mixture composed of the composite metal and a ferrous metal such as Co in the case of the sintered hard alloy. Said layer is further a mixture composed of Al2O3, Cr3C2, TiO2 or the like and >=1 kind among MgO, SiO2, V2O3 and CaO or these compsn. added and mixed with a metal or alloy binder in the case of the cermet on ceramic.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) The present invention relates to a slab support member for continuous casting that has excellent wear resistance and corrosion resistance.

In continuous casting equipment, roll support has traditionally been used to support the slab that has passed through the mold, but as casting speeds have increased in recent years, improvements have been made to prevent breakouts and improve cooling efficiency. For this reason, cooling plates, cooling grids, combs, etc. are being used alone or in combination with rolls. Copper, its alloys, or cast iron are used as materials for these materials, but they are susceptible to wear and scratches due to contact with cast slabs, as well as corrosion and cracking caused by spray water under high temperature and humidity conditions.
The disadvantage was that it had a short service life and had to be replaced frequently.

This is because in the case of copper material, the hardness of pure copper itself is Hν=8
Considering that it is about 0 to 100, wear resistance cannot be expected from the viewpoint of hardness alone.

In addition, in the case of cast iron materials, the replacement cycle is normal3.
When used from 00 to 400ch, the parts that come into contact with the slab become ferrite due to decarburization, and the hardness decreases to Hv<200. Moreover, the layer thickness reaches a maximum of 15 InIn.

That is, for these reasons, when copper or cast iron is used alone, various types of damage tend to occur at the parts that come into contact with the slab, resulting in a short service life.

The present invention relates to a slab support member that eliminates the above-mentioned drawbacks and has a long service life. Heat resistant in parts.

This is a slab support member for continuous casting characterized by being coated with a coating layer made of metal, alloy, cermet, or ceramic that is highly wear resistant and corrosion resistant.

The coating layer having high wear resistance and corrosion resistance used herein refers to the following.

(1) Metal 1 alloys: Ni, Cr, Co or their alloys Ni-Cr
+Co-Cr as a main component or stainless steel, and the construction method is plating or thermal spraying. Typical plating methods include Ni or Co with We
There are some types of materials (3) containing one or more of Mo+Cr+P, and the following are typical examples of thermal spraying methods.

(a) Co-Cr system (weight%) (b) Ni-Cr system (4) (c) Stainless steel system (weight%) (2) Cemented carbide 10 or ■iC alone or in combination It is made of a mixture of metal and iron group metals such as Co, and the method of construction is preferably thermal spraying.

(3) Ceramics, ceramics ^1. IOj+Cr, CX+TiO
, +ZrO, +Si, N, + etc. M g O* S 1
02 + Oj, a mixture of one or more types of CaO,
The cermet is a mixture of the above-mentioned composition and a metal or alloy binder, and the preferred method of application is thermal spraying. Next, examples of the present invention will be described.

<Example 1> The parts that contact the slab of the cooling grid made of spheroidal graphite cast iron (5) were degreased with alkaline water and then washed with water, and then treated with sodium hydroxide (409/I) and sodium monide (309/I). /I) in a mixture of 5^/da”
After performing anodic electrolytic degreasing under conditions of x-minutes and washing with water,
After activating the surface by immersing it in a solution of %H + 3% HF for 15 minutes, a 50 μl thick Ni underplating was performed under the following conditions.

(Underlying plating conditions) Nickel sulfate 2509/j Liquid composition Nickel chloride 459/1 Boric acid 30g/j Liquid temperature 55°C Liquid pH 4°5 Dk 3A/dIIL Plating time 2 hours Then, the surface roughness was reduced to approximately 30 μm using syrup blasting. The surface is roughened, and then a Ni-Cr self-fluxing alloy having the composition listed in the table shown in (1) (b) is thermally sprayed onto the surface (6) so that the layer thickness is as much as 0.5+nm, 900-1
Heat treatment was performed at 000°C. Through this heat treatment, the base material, the base Nl2, and the Ni-Cr self-fluxing alloy sprayed layer on the surface are metallurgically bonded, and strong adhesion can be obtained.

The hardness of the surface coating layer obtained in this way is Hv550~
600, and the hardness of spheroidal graphite cast iron before coating is Hv
It is considerably improved compared to 250, and the cooling grid made of uncoated spheroidal graphite cast iron is 300 to 400.
When using Ch, the amount of wear was large and cracks were generated, so it had to be discarded, whereas as mentioned above (Ni)
The product of the present invention, which was coated with a N-Cr self-fluxing alloy coating layer, withstood use of 1000 to 1200 Ch under the same conditions, and showed almost no corrosion.

<Example 2> The surface of the part of the silver-containing copper com material that comes into contact with the slab was roughened to a roughness of about 30 μm (liquid honing), and then subjected to alkaline degreasing, water washing, and pickling. After water washing → surface activation, 250 μm thick Ni was prepared under the following conditions.
-P alloy plating was performed.

(7) (Ni-P alloy plating conditions) Nickel sulfate aoog/l Liquid composition Phosphoric acid 209/j Phosphorous acid 209/1 Liquid temperature 60°C Phosphorous acid 20g/j Liquid temperature 60°C Liquid pH 1.8 Dk 8A/ da+” Plating time: 30 hours (platinum was used for the anode) The plated layer formed in this way was subjected to precipitation hardening at 300°C for 2 hours, and the hardness before precipitation hardening was Hν45.
0 was normalized to Hv850 after processing.

Uncoated com material is approximately 1.6 when using 200 Ch per - time.
+u+ wear occurred and had to be discarded after 4 to 5 reworks, but Ni-P alloy (
8) For products with a coating layer, the amount of wear after using 200Ch is approximately 0.
．． The number of reworks was as low as 2 to 0.3 av+, and the number of reworks exceeded 10, and the service life was significantly extended with almost no corrosion.

<Example 3> After applying the same pretreatment as in Example 2 to the part of the cooling plate made of deoxidized copper that comes into contact with the slab, the base Ni plating was performed under the following conditions to a layer thickness of 50μ■ as much as possible. Ta.

(Substrate N1 plating conditions) Nickel sulfamate 4009/ J Liquid composition Nickel chloride 109/ J Boric acid 409/ 1 Liquid temperature 55°C Liquid pH 4.0 K 3 A/di+” Plating time 2 hours (9) After that, the following Under the conditions, the layer thickness of NI-W alloy plating is 2
The thickness was as much as 50 μm.

(Ni-W alloy plating conditions) Nickel citrate 9597 J Liquid composition Sodium tungstate 549/J (9
) Citric acid 54 11 Liquid temperature 60°C Liquid pH 3.5 Dk 5^/dI+” Plating time 30 hours (Platinum was used as the anode) The cooling grid of this example obtained in this way The hardness is Hv600, and the amount of wear during rotation is approximately 1/4 of that of conventional uncoated cooling grids.
115, the number of reworks was approximately three times greater, and there was almost no corrosion, significantly improving its service life.

(10) <Example 4> The part of the cooling grid made of spheroidal graphite cast iron that comes into contact with the slab was degreased with solvent and degreased with alkaline, then washed with water, and then grid blasted to a surface roughness of 30 μm.
It was set as the degree.

After a Ni--Cr self-fluxing alloy was sprayed on the rough surface as a base layer, a ceramic material such as ZrO was sprayed on the surface layer. Thereafter, the adhesion between the base material and the surface layer was strengthened by heat treatment at 900 to 1000°C.

Without heat treatment or base treatment, the adhesion strength was only about 5kg12 at most, which made it unusable, but depending on the base treatment and heat treatment at 900-1000℃, the adhesion strength increased to 10-15kg/ll112. It has been improved and is now usable.

The cooling grid of this example thus obtained has a surface hardness of Hv > 700, and a lifespan of 30 Hv compared to the conventional one.
It is now possible to extend the range from 0 to 400 channels to over 1,500 channels.

<Example 5> (11) The part of the cooling grid made of spheroidal graphite cast iron that comes into contact with the slab was degreased with solvent and degreased with alkali, and then washed with water, and then grid blasted to a surface roughness of 30 μff.
It was set to about i.

After spraying Ni-Cr self-fluxing alloy as a base layer on the rough surface, the surface layer contains (C'JCJL) 75%+
(Ni50-Cr50) A cermet material containing 25% by weight was thermally sprayed. Thereafter, the adhesion between the base material and the surface layer was strengthened by heat treatment at 900 to 1000°C. Here, if the treatment temperature exceeds 1050°C, the hardness of the surface layer will rapidly decrease and the adhesion will also decrease.
A heating temperature of 1000°C or less is desirable.

The cooling grid of this example obtained in this way has a surface hardness of Hv>soo or more, and a lifespan of 300~. It is now possible to extend the number of channels for aooch to over 1500 channels.

In addition to the above embodiments, a cooling plate made of 5541 material is coated with Ni or C-C alloy, or N1-^1 alloy as a base layer, and the surface layer is made of 8L-0.

Ceramic materials such as TiO, or Ni-Cr-
Tic.

(12) A practical test was carried out using a cermet material such as Ni-5i3N, etc., and it was confirmed that it could withstand practical use.

As described above, according to the present invention, a coating layer with high wear resistance and corrosion resistance is applied to the parts of various members that support the slab under high temperature and high humidity that come into contact with the slab. Abrasion and corrosive wear are less likely to occur, compared to conventional uncoated parts.
Its service life can be significantly improved.

In addition to the cooling plates, combs, and cooling grids shown in the above embodiments, the present invention can be applied to various slab supporting members such as rolls, king bars, and shoes.

Patent applicant: Nippon Steel Corporation (1 other person) Agent Noriharu Ariyoshi (13)

Claims (1)

[Scope of Claims] 1. The main body of the slab support member made of cast iron, general structural steel, copper or copper alloy, at least in the portion that comes into contact with the slab, is made of a metal or alloy that is highly heat resistant, wear resistant, and corrosion resistant. A slab support member for continuous casting characterized by being coated with a cermet or ceramic coating layer. 2. In the slab supporting member according to claim 1, the sonocoating layer is made of Ni, Cr, Co, N1-W,
Ni-Mo. Ni-P, Co-W, Co-No, Co-P,
Something like Ni-Cr or Co-Cr. 3. The slab supporting member according to claim 1 has a coating layer of N1-Cr-Tic, Ni-5ij.
Something like %. 4. The support member for the slab according to claim 1 has a coating layer of Zroxp Cr, rc2 #^1. O
J. Something like Ti0a.