CN102517501A

CN102517501A - High-strength rare-earth steel rail containing Cr and V

Info

Publication number: CN102517501A
Application number: CN2011104509572A
Authority: CN
Inventors: 张智; 陈建军; 张晓光; 刘建国; 智建国; 李平; 张文平; 井溢农; 赵桂英
Original assignee: Baotou Iron and Steel Group Co Ltd
Current assignee: Baotou Iron and Steel Group Co Ltd; Inner Mongolia Baotou Steel Union Co Ltd
Priority date: 2011-12-30
Filing date: 2011-12-30
Publication date: 2012-06-27

Abstract

The invention relates to a high-strength abrasion-proof rare-earth steel rail belonging to the technical field of metallurgical products. The chemical components of the steel rail comprise C, Si, Mn, P, S, Cr, V and RE. By adding Cr and V alloy and rare earth, each element of the steel rail is mutually complemented through adopting a mode of adding a rare-earth cored wire after refining. The strength and the abrasion resistance of the steel rail are increased, the comprehensive performance is enhanced, and the welding performance and the heat-treatment performance are improved. The steel rail is suitable for an important trunk line with large traffic volume and has extensive application prospect.

Description

A kind of high-strength rare earth rail that contains Cr, V

Technical field

The invention belongs to metallurgical technology field, relate to a kind of method of manufacture of metallurgic product.

Background technology

Railway is the Aorta of Chinese national economy, and along with rapid development of economy, transportation by railroad is also busy day by day.Because train axle weight, road speed and density increase substantially, the service condition of rail is more and more abominable, and shorten work-ing life greatly.Particularly at heavy duty or sharp radius curve, because on the low side, the undercapacity of rail hardness, rail is produced seriously wear and tear and come in contact tired hurt, cause rail to reduce work-ing life, maintenance of way expense increases, and has a strong impact on traffic safety.For the heavy haul transport circuit, domestic hot rolling 980MPa level (U75V) rail can not satisfy the requirement that circuit uses, is badly in need of researching and developing the more rail of high firmness and intensity rank; For sharp radius curve section circuit, need the suitable high firmness of exploitation and the rail of intensity rank.

Summary of the invention

The objective of the invention is on the basis that contains Cr, V alloy,, develop that a kind of high-temp plastic is good, crack sensitivity is low through adding rare earth; Rail strength is high; Welding property and heat treatment performance obviously improve, and wear resisting property and corrosion resisting property are good, the novel rare-earth rail of long service life.

The present invention takes following measure to realize:

A kind of rare earth is handled contains Cr, the high-strength rail of V, and the chemical ingredients and the content of rail are designed to (%):

Producing and manufacturing technique is:

With getting into converter smelting after the hot metal pretreatment, tapping temperature is 1620-1660 ℃, and the tapping carbon content is 0.11-0.13%; Get into the refining of LF stove after adding Cr, V alloy; Add rare earth bundle component wire and get into the VD stove, carry out continuous casting, heat the de-scaling of laggard horizontal high voltage water; Be rolled then, align, detect a flaw, process back inspection warehouse-in.

Technological process of production summary is: converter smelting → L F stove refining → VD vacuum-treat → continuous casting → process furnace heating → rolling → aligning → flaw detection → processing.

CrVRE rail of the present invention belongs to the high-strength wearable rail, and the impact of performance is following:

1, intensity is high, good combination property, and particular case is seen shown in the table 1.

Table 1 over-all properties detected value

?	Rm(MPa)	A(％)	Hardness (HB)
				On average	1106.09	10.70	326.18
Minimum value	1080	9	304.8
				Peak	1160	13	350

2, wear resisting property is good, long service life

The average abrasion 0.1687g of CrVRE rail lacks 0.0429g than the average abrasion 0.2116g of U75V rail, and wear resisting property improves 20.3%.

3, corrosion resistance and good

Under same test period and etching condition, the corrosion weight loss of CrVRE rail is 318g/m ², U75V is 361g/m ², relative difference is obvious, explains that the corrosion resistance nature of this rail has improved 14% than U75V.

4, the CrVRE rail not only can use in hot rolling, can also weld with thermal treatment and use, and hot rolled rail Rm reaches more than the 1080MPa, can reach more than the 1280MPa after the thermal treatment.

Embodiment

Pretreated 100 tons of molten iron are got into converter smelting, behind composition design adding Cr, V alloy, get into the refining of LF stove, add rare earth bundle component wire in proportion, after entering VD stove carries out vacuum-treat, carry out continuous casting, be rolled then, align, detect a flaw.

Technological process of production summary is: converter smelting → LF stove refining → VD vacuum-treat → continuous casting heating → stove heating rolling → aligning → flaw detection → processing.

The chemical ingredients and the content of strand see the following form (Wt%):

C	Si	Mn	P	S	Cr	V	RE (add-on)
								0.77	0.68	0.93	0.018	0.005	0.3	0.08	0.02

1, smelts

The carbon content of converter terminal molten steel, phosphorus content and tapping temperature are as shown in the table.

The test grade of steel	Tapping temperature, ℃	The tapping carbon content, %	The tapping phosphorus content, %
				?	1642	0.12	0.012

Converter adds alloy, through the refining of LF stove, adds cored-wire before the VD.

Continuous casting superheating temperature and pulling rate control

The test grade of steel	Superheating temperature, ℃	Pulling rate, m/min
			?	28	0.70

2, rolling

Steel billet the process furnace internal heating time greater than 3 hours, the test steel the steel billet start rolling temperature be 1138 ℃, roll into the 60kg/m rail through BD1, BD2, CCS, the rail qualification rate is 98.7%.

3, performance

?	Tensile strength, MPa	Elongation, %	Tread hardness, HB
				?	1100	10.5	339
Performance requriements	≥1080	≥9	≥300

Advantage of the present invention is: in rail, add Cr, V and RE simultaneously; Improved the over-all properties of rail; Improve welding property and heat treatment performance, increased the intensity (reaching more than the 1080MPa) of rail, the wear resistance and the work-ing life of having improved rail; It is applicable to freight volume big trunk railway, wide application prospect is arranged.

Claims

1. high-strength rare earth rail that contains Cr, V is characterized in that the chemical ingredients of rail and weight percent content are: C 0.65～0.82, Si 0.50～0.80, Mn 0.70～1.20, P≤0.025, S≤0.025, Cr0.20～0.40, V≤0.10, RE (add-on)≤0.03, all the other are matrix Fe and micro impurity element.

2. a kind of method of manufacture that contains the high-strength rare earth rail of Cr, V of characteristic according to claim 1 is characterized in that tapping temperature is 1620-1660 ℃ with getting into converter smelting after the hot metal pretreatment; The tapping carbon content is 0.11-0.13%, adds to get into the refining of LF stove behind Cr, the V alloy, adds to get into the VD stove behind the rare earth bundle component wire and carry out vacuum-treat; Carry out continuous casting then, the continuous casting superheating temperature is 25-30 ℃, and the continuous casting pulling rate is 0.65-0.75m/min; Heat the de-scaling of laggard horizontal high voltage water, be rolled then greater than 3 hours heat-up time; The steel billet start rolling temperature is 1120-1150 ℃, and back inspection warehouse-in is processed in rolling, aligning, flaw detection; Technological process of production summary is: converter smelting → LF stove refining → VD vacuum-treat → continuous casting → process furnace heating → rolling → aligning → flaw detection → processing.