CN102212777B - Surface strengthening method of crystallizer of continuous casting and rolling machine - Google Patents

Abstract

The invention discloses a surface strengthening method of a crystallizer of a continuous casting and rolling machine, comprising the following steps of: before spraying, firstly polishing the surface of a copper crystallizer through use of a flint glass paper to remove scale and oil contamination on the surface; performing sand blasting on a surface to be sprayed in a range of 100-300 mm by using compressed air at 3-4 atmospheric pressures; stopping sand blasting till the surface of the copper crystallizer cannot reflect light; cleaning sand on the surface by using compressed air; in the event of spraying, spraying the fixed copper crystallizer by using a plasma spray gun, wherein the spraying material is powder alloy; the powder alloy contains NiCr, CrC, Ni-Co and NiFe; the spraying process comprises the following parameters: the spraying current is 700 A, the spraying voltage is 50+/-0.5 V, the number of the spraying return cycle is 5, the main atmospheric pressure (Ar) is 420 KPa, the powder feeding pressure (Ar+H2) is 200 KPa, the spraying distance is 90 mm, the spraying speed of the spray gun is 500 mm/s, and the powder feeding speed is 1.138 g/s; and after spraying, mechanically processing the surface of the coating till required fineness and size are achieved.

Description

The surface reinforcing method of the crystallizer of continuous casting and continuous rolling mill

Technical field

The present invention relates to a kind of surface reinforcing method, particularly a kind of surface reinforcing method of crystallizer of continuous casting and continuous rolling mill.

Background technology

Crystallizer is the key part on the continuous casting and continuous rolling mill, and its quality directly affects detecting continuous casting billet surface quality, continuous caster operating rate and continuously cast bloom cost.The development of high-efficient continuous casting technology is had higher requirement to the crystallizer quality, and high strength, high-wearing feature, high thermal fatigue and good thermal conductivity become the important indicator of weighing the crystallizer quality.In use mainly there are the problems such as edge abrasion, wide thermal crack, leptoprosopy contraction, corrosion in crystallizer.

At present, the crystallizer of domestic production mainly is to adopt electric plating method to electroplate Cr layer, Ni layer, Ni+Cr layer, Ni-Fe layer and plating Ni-Co layer at the copper primary surface.At present, the most representative method is the broadside copper coin electroplating surface Ni-Co coating to crystallizer, to narrow limit copper coin surface spraying Ni-Cr alloy coat.Adopt electroplating technology that crystallizer surface is carried out the work-ing life that intensive treatment has improved crystallizer to a great extent.But all there is in various degree defective in present various coating, mainly are that the production cycle is long, and the coating of electroplating 1.5mm thickness needs 120～140 hours, and power consumption and liquid waste disposal expense are high.In addition, electroplating industry also is heavy polluted industry, has begun to seek very early the substitute technology of plating in developed country, for example, the U.S. has promulgated decree January 25 nineteen ninety-five " federal registration ", and durionise was forbidden producing in the U.S. after on January 25th, 1997.China has also begun to enact a law and has limited and the rectification electroplating industry, also begins to close in a large number with serious pollution little Electroplate Factory since environmental administration in 1996, and has implemented " clean production method " on January 1st, 2003.Therefore in the urgent need to seeking a kind of new copper plate of crystallizer surface strengthening technology, come the use properties of replacing electroplating technological improvement crystallizer.

Summary of the invention

The surface reinforcing method that the purpose of this invention is to provide a kind of crystallizer of continuous casting and continuous rolling mill, the method is to adopt the Supersonic Plasma Spraying preparation to add the matrix material alloy coat of wild phase at the copper matrix, can increase substantially wear resisting property and thermal fatigue resistance, the method can improve work-ing life and the production efficiency of crystallizer, reduce production cost and the reducing polluted emission of crystallizer, all can bring larger economic benefit to copper plate of crystallizer factory, copper plate of crystallizer reparation factory and steelworks.

The present invention's method may further comprise the steps:

(1), before spraying, at first polished through flint paper in the copper crucible surface, remove scale and the greasy dirt on surface, to treat that spray plane carries out sandblasting with 3～4 normal atmosphere pressurized air in 100～300mm scope, until stop sandblast behind the no-reflection of copper crucible surface, the sand blasted surface grains of sand are removed clean with pressurized air again;

(2), when spraying, use plasma gun that securing copper crucible is sprayed, the material of spraying is powdery alloy, this powdery alloy includes NiCr, CrC, Ni-Co and NiFe;

(3), the parameters in the Plasma Spraying Process Using is:

Spraying current is 700A; Spray voltage is 50 ± 0.5V; Spraying circulation backhaul is 5 times; Main air pressure (Ar) is 420KPa; Powder feeding air pressure (Ar+H ₂) be 200KPa; Spray distance is 90mm; The spray speed of spray gun is 500mm/s; Powder feed rate 1.138g/s;

(4), the spraying after coatingsurface is carried out mechanical workout, reach desired smooth finish and size.

Beneficial effect of the present invention:

1, economizes on resources, reduced discharging and pollution.

2, compare the coating that the present invention forms with electroplated Ni-Co coating:

(1) hardness is more than the HV900, is 3 times of electroplated Ni Co coating, and wear-resisting material abrasion characteristic is 2～3 times of Ni-Co coating in the time of 700 ℃;

(2) thermal shock resistance in the time of 700 ℃ reaches 2000 times;

(3) coated material is applied on the crystallizer, and steel transportation amount reaches 12～150,000 tons, is 2～3 times of electroplated Ni-Co coating;

(4) production cost is 60～70% of electroplated Ni-Co.

Embodiment

The present invention's method may further comprise the steps:

1, before spraying, at first polished through flint paper in the copper crucible surface, remove scale and the greasy dirt on surface, to treat that spray plane carries out sandblasting with 3～4 normal atmosphere pressurized air in 100～300mm scope, until stop sandblast behind the no-reflection of copper crucible surface, the sand blasted surface grains of sand are removed clean with pressurized air again;

When 2, spraying, use plasma gun that securing copper crucible is sprayed, the material of spraying is powdery alloy, and this powdery alloy includes NiCr, CrC, Ni-Co and NiFe;

3, the parameters in the Plasma Spraying Process Using is:

Spraying current is 700A; Spray voltage is 50 ± 0.5V; Spraying circulation backhaul is 5 times; Main air pressure (Ar) is 420KPa; Powder feeding air pressure (Ar+H ₂) be 200KPa; Spray distance is 90mm; The spray speed of spray gun is 500mm/s; Powder feed rate 1.138g/s;

4, after the spraying coatingsurface is carried out mechanical workout, reach desired smooth finish and size.

Employed plasma gun is the UP20 humanoid robot control spray gun of control able to programme in the step 2.

Claims (1)

1. the surface reinforcing method of the crystallizer of a continuous casting and continuous rolling mill, the method may further comprise the steps:

(1), before spraying, at first polished through flint paper in the copper crucible surface, remove scale and the greasy dirt on surface, to treat that spray plane carries out sandblasting with 3～4 normal atmosphere pressurized air in 100～300mm scope, until stop sandblast behind the no-reflection of copper crucible surface, the sand blasted surface grains of sand are removed clean with pressurized air again;

(2), when spraying, use plasma gun that securing copper crucible is sprayed, the material of spraying is powdery alloy, this powdery alloy includes NiCr, CrC, Ni-Co and NiFe;

(3), the parameters in the Plasma Spraying Process Using is:

Spraying current is 700A; Spray voltage is 50 ± 0.5V; Spraying circulation backhaul is 5 times; Main air pressure Ar is 420KPa; Powder feeding air pressure Ar+H ₂Be 200KPa; Spray distance is 90mm; The spray speed of spray gun is 500mm/s; Powder feed rate 1.138g/s;

(4), the spraying after coatingsurface is carried out mechanical workout, reach desired smooth finish and size.