CN1064566C

CN1064566C - Centrifugal casting method for producing composite high-speed steel rollers

Info

Publication number: CN1064566C
Application number: CN97100083A
Authority: CN
Inventors: 宫开令; 张欣
Original assignee: TANGSHAN LIANQIANG METALLURGICAL ROLLS CO Ltd; China Iron and Steel Research Institute Group
Current assignee: TANGSHAN LIANQIANG METALLURGICAL ROLLS CO Ltd; China Iron and Steel Research Institute Group
Priority date: 1997-02-24
Filing date: 1997-02-24
Publication date: 2001-04-18
Anticipated expiration: 2017-02-24
Also published as: CN1179368A

Abstract

一种离心复合高速钢轧辊的生产方法，主要特征是轧辊外层材质为高速钢，轧辊芯部材质为合金球墨铸铁，两种不同材料采用离心铸造复合而成。外层钢水在浇注前加入稀土进行变质处理，稀土的加入量为0.03～0.5%。同时，在外层钢水浇注后加入保护剂保护，以防止外层内表面的氧化，保护剂的加入量为3～5Kg/m²，外层钢水的浇注温度为1400～1550℃，芯部铁水的浇注温度为1350～1450℃。本发明具有生产成本低，所产轧辊使用寿命长等优点，适用于高速钢轧辊的离心复合制造。The invention discloses a production method of a centrifugal composite high-speed steel roll, which is mainly characterized in that the material of the outer layer of the roll is high-speed steel, the material of the core of the roll is alloy ductile iron, and the two different materials are compounded by centrifugal casting. The outer layer of molten steel is modified by adding rare earth before pouring, and the amount of rare earth added is 0.03-0.5%. At the same time, add a protective agent after pouring the outer layer of molten steel to prevent oxidation of the inner surface of the outer layer. The amount of protective agent added is 3-5Kg/m ² . The pouring temperature is 1350-1450°C. The invention has the advantages of low production cost, long service life of produced rolls, etc., and is suitable for the centrifugal composite manufacturing of high-speed steel rolls.

Description

The production method of centrifugal composite high-speed steel roller

The invention belongs to the high-speed steel roll manufacturing technology, mainly be applicable to the centrifugal compound manufacturing of the high-speed steel roll that the steel rolling industry is required.

High-speed steel roll is neoteric in recent years a kind of new roller, and its sphere of action is not only applicable to the cold and hot working roll that rolls of strip-mill strip, but also is applicable to the working roll of various bar and shape mills, has the prospect of using widely.The production method of centrifugal composite high-speed steel roller is compared with continuous casting composite algorithm, electroslag remelting process and high temperature insostatic pressing (HIP) method, has advantages such as equipment investment is few, production cost is low, method of operating is easy, constant product quality.This production method at first is that the molten steel with skin of the roll pours in the centrifuge casting mold with certain rotation speed; intact back adds special protective agent protection at outer field inner surface; when outer molten steel has just solidified; pour into the alloy nodular cast iron molten iron of core again, make the material of two kinds of different performances reach metallurgical binding completely.To guarantee on the one hand and solidify skin to reach whole metallurgical binding for pouring into of core molten iron, to reduce as far as possible on the other hand solidifying outer field fusing, cause the reduction of roller neck intensity to prevent final core alloy too high levels, on combination process, to control especially simultaneously, cause the reduction of binder course intensity with the diffusion that reduces the binder course alloy.

In the production method of existing centrifugal composite high-speed steel roller, although the alloy content of skin of the roll is enough high, but the netted eutectic carbide amount of as cast condition is a lot, both made by heat treatment and also be difficult to all eliminate, cause reduce greatly the service life of roll, and core of the roll material employing steel alloy, the manufacturing cost costliness is as Japan Patent JP157571.

Patent CN1070600A discloses a kind of production method of centrifugally compounded nodular graphite cast iron roller; Its skin and core material are spheroidal graphite cast-iron, do not realize that cladding material is a high-speed steel, and core material is the purpose of spheroidal graphite cast-iron.

The object of the present invention is to provide a kind of production cost low, simple to operate, the production method of the centrifugal composite high-speed steel roller of long service life.

In order to achieve the above object, the present invention has adopted following major technique measure:

(1) outer material of roll adopts high-speed steel, and the core of the roll material adopts alloy nodular cast iron.

The chemical composition of skin of the roll molten steel (weight %) is: C1.2-2.5%, Si0.3-1.5%, Mn0.4-1.0%, Ni＜1.5%, Cr3.0-8.0%, Mo2.0-7.0%, V2.0-7.0%, W1.0-5.0%, RE0.01-0.5%, P＜0.05%, S＜0.05%, surplus is Fe.

The chemical composition of core of the roll molten iron (weight %) is: C3.0-3.8%, and Si2.2-3.2%, Mn0.3-0.8%, Ni0.2-2.0%, Mg0.03-0.1%, RE＞0.03%, P＜0.1%, S＜0.03%, surplus is Fe.

(2) outer molten steel adopts rare earth processings of go bad, and the core molten iron adopts rare earth-Si-Fe-Mg and ferrosilicon powder to carry out nodularization and inoculation, and the core molten iron adopts a certain amount of instant inoculation to spread and the influence that causes to core with the elimination outer layer alloys simultaneously.

(3) skin of the roll high-speed steel and core alloy spheroidal graphite cast-iron adopt centrifugal casting to be composited, to reach complete metallurgical binding.

(4) behind outer pouring molten steel, add a kind of protective agent outer inner surface is protected, in case oxidation, this protective agent is the disclosed centrifugal casting molten-slag of ZL92105533.1, described protectant addition is 3-5kg/m ²

(5) roll will be heat-treated before fine finishining, makes outer tissue obtain granular carbide and tempered martensite.

The centrifugal recombination process of roll is as follows: at first skin of the roll molten steel and core molten iron are smelted respectively in two electric furnaces; the skin of the roll molten steel adopts the rotten processing of rare earth; the addition of rare earth is that molten steel amount (weight %) is 0.03～0.5%; outer molten steel after rotten the processing is poured in the centrifuge casting mold with certain rotation speed; outer pouring molten steel temperature is 1400～1550 ℃; the temperature of casting mold is 50～250 ℃ during cast; the paint thickness of casting mold is 1-5mm; after outer molten steel has watered; add a kind of protective agent protection at outer field inner surface; described protective agent is the disclosed centrifugal casting molten-slag of ZL92105533.1, and protectant addition is 3～5KG/m ²Behind outer molten steel solidification, pour into the core molten iron again, when tapping a blast furnace, described core molten iron carries out nodularization and inoculation with rare earth-Si-Fe-Mg and ferrosilicon powder, the addition of rare earth-Si-Fe-Mg is the 1.0-2.5% of molten iron total amount (weight %), the addition of ferrosilicon powder is the 0.3-1.0% of molten iron total amount (weight %), the core molten iron adopts ferrosilicon powder to carry out instant inoculation when cast and handles, the addition of described ferrosilicon powder is 0.05～0.3% of a core molten iron total amount (weight %), the pouring temperature of core molten iron is 1350～1450 ℃, makes two kinds of different metals reach metallurgical binding completely.

Compared with prior art, the present invention has following advantage:

(1) outer molten steel adopts the rare earth processing of go bad, and the centrifugal composite high-speed steel roller of core employing alloy nodular cast iron has that equipment investment is few, and production cost is low, advantages such as the easy and constant product quality of method of operating.

(2) owing to the formation of granular and thin massive carbide, not only wearability is good to make roll, and toughness also improves greatly.

(3) roll is used for the strip-mill strip working roll and compares with existing high nickel chromium triangle infinitely chilled ductile cast iron roll and can improve 3-4 service life doubly, is used for bar and shape mill and compares with existing roll, can improve 2-3 service life doubly.

(4) this kind roll can replace the carbon tungsten roller ring of high-speed rod-rolling mill finish rolling leading portion.Reduce production costs greatly.

(5) owing to the roll raising in service life, reduced the roll change number of times, the operating rate of milling train is significantly improved.

Embodiment

Adopt the production method of centrifugal composite high-speed steel roller of the present invention, manufacture experimently three batches of rolls, the chemical composition of the three batches of skin of the roll molten steel and core molten iron is as shown in table 1, and centrifugal combination process parameter is as shown in table 2.

The three batches of rolls are respectively applied for the mill coil milling train and high rod-rolling mill gives finishing stand, and the steel rolling amount is as follows altogether:

The high NiCrMo indefinite chill roll of former employing, access times are about 10 times, the steel rolling amount is about 3000 tons altogether.Now adopt the total steel rolling amount of embodiment A and B to reach 12000 and 12500 tons.The high NiCrMo indefinite chill roll of former employing, the steel amount is about 13000 tons altogether, now adopting the total steel rolling amount of Embodiment C is 35000 tons.

Table 1 embodiment skin of the roll and core chemical composition (Wt%)

Classification	The position	Chemical composition (Wt%)
		Chemical composition (Wt%)												C	Si	Mn	P	S	W	Cr	Mo	V	Ni	RE	Mg
		A	Outer	2.35	1.41	0.85	0.049	0.042	1.46	4.05	2.25	2.46	0.24	C	Si	Mn	P	S	W	Cr	Mo	V	Ni	RE	Mg	0.029	/
Core	3.46		Outer	2.35	1.41	0.85	0.049	0.042	1.46	4.05	2.25	2.46	0.24	2.57	0.52	0.043	0.026	/	/	/	/	0.49	0.047	0.042		0.029	/
Core	3.46		B	Outer	1.25	0.48	0.41	0.031	0.036	4.82	6.86	6.45	5.93	2.57	0.52	0.043	0.026	/	/	/	/	0.49	0.047	0.042	1.47	0.043	/
Core	3.53	2.82		Outer	1.25	0.48	0.41	0.031	0.036	4.82	6.86	6.45	5.93	0.48	0.046	0.017	/	/	/	/	0.96	0.036	0.056		1.47	0.043	/
Core	3.53	2.82		C	Outer	1.96	0.78	0.65	0.041	0.035	2.25	5.12	4.06	0.48	0.046	0.017	/	/	/	/	0.96	0.036	0.056	4.93	0.58	0.063	/
Core	3.49	2.75	0.66		Outer	1.96	0.78	0.65	0.041	0.035	2.25	5.12	4.06	0.038	0.021	/	/	/	/	1.50	0.041	0.044		4.93	0.58	0.063	/

The centrifugal combination process parameter of table 2 embodiment

Classification	Barrel diameter mm	Outer pouring molten steel temperature ℃	Core molten steel pouring temperature ℃	Outer rare earth adding quantity %	Water injection molding temperature ℃	Paint thickness mm
A	φ300	1520℃	1380℃	0．15	230℃	2．5
B	φ310	1540℃	1430℃	0．10	170℃	1．5
C	φ310	1470℃	1400℃	0．30	180℃	1．5

Claims

1. A production method for centrifugal composite high-speed steel rolls. First, pour the metamorphic outer layer of molten steel into a centrifuge mold with a certain rotational speed. The pouring temperature of the outer layer of molten steel is 1400-1550°C. The mold temperature is 50-250°C. When the outer layer of molten steel is solidified, the core molten iron is poured in. The pouring temperature of the core molten iron is 1350-1450°C. It is characterized in that:

(1) The outer material of the centrifugal composite roll is high-speed steel, and the core material of the roll is alloy ductile iron;

(2) The chemical composition (weight%) of the outer high-speed steel of the centrifugal composite roll is; C1.2-2.5%, Si0.3-1.5%, Mn0.4-1.0%, Ni<3 .0%, Cr3.0-8.0%, Mo2.0-7.0%, V2.0-7.0%, W1.0-5.0%, RE0.01-0.5%, P <0.05%, S<0.05%, the rest is Fe.

(3) The outer layer high-speed steel of the centrifugal composite roll adopts rare earth to carry out metamorphism treatment, and the addition amount of rare earth is 0.03-0.5% of molten steel amount (weight %);

(4) After the outer layer of molten steel is poured, add a protective agent, namely the centrifugal casting slag disclosed in ZL92105533.1, to protect the inner surface of the outer layer, and the addition of the protective agent is 3-5kg/m ² ;

(5) When tapping the molten iron in the core, use rare earth ferrosilicon magnesium and ferrosilicon powder for spheroidization and inoculation treatment, and the addition amount of rare earth ferrosilicon magnesium is 1.0-2.5 of the total amount of molten iron (weight %) %, the added amount of ferrosilicon powder is 0.3-1.0% of the total amount of molten iron (weight %).