CN105671429A

CN105671429A - High-performance E+ steel containing rare earth

Info

Publication number: CN105671429A
Application number: CN201610185788.7A
Authority: CN
Inventors: 王光明; 张挨元; 张秀清; 单水维; 李志杰; 高伟; 王虎明; 张小东; 李卫国; 左文博; 刘江; 王瑞
Original assignee: Inner Mongolia First Machinery Group Corp
Current assignee: Inner Mongolia First Machinery Group Corp
Priority date: 2016-03-30
Filing date: 2016-03-30
Publication date: 2016-06-15

Abstract

The invention relates to high-performance E+ steel containing rare earth, which solves the problem of E cast steel of the Ministry of Railways. The high-performance E+ steel comprises the following components according to weight percent: 0.20 to 0.30 percent of C, 0.20 to 0.50 percent of Si, 1.20 to 1.70 percent of Mn, 0.30 to 0.80 percent of Cr, 0.35 to 0.80 percent of Ni, 0.10 to 0.30 percent of MO, less than or equal to 0.01 percent of P, less than or equal to 0.01 percent of S, less than or equal to 0.30 percent of Cu, 0.02 to 0.2 percent of RE, Fe and trace impurities as the rest, wherein the RE prefers to La and Se. The high-performance E+ steel has the advantages of less alloying element, low alloy content, high strength, simple production process and low cost and is suitable for ultrahigh-strength railway vehicle steel castings. By adjusting heat treatment, the high-performance E+ steel has good strength and impact toughness and high fatigue strength and abrasion resistance.

Description

A kind of containing rareearth high-quality E+ steel

Technical field:

The present invention relates to a kind of containing rareearth high-quality cast steel, belong to Low-alloy high-strength cast steel technical field.

Background technology:

At present, there is crackle in Datong-Qinhuangdao Railway fortune coal C80 type open-top car 16 type, 17 type hitches, and this hitch material is ZG25MnCrNiMo-E level cast steel, and cracking failure analysis shows, crackle Producing reason is fatigue fracture and brittle fracture. Hitch bears very big pull strength, impulsive force, tension and compression alternating force when being on active service, its hook bolt, pin-and-hole, hook body and 16 positions, type draw gear tail convex bulb there is also abrasion, and work under the long-term environment in the open of hitch, northern China winter temperature is low reaches-20～-40 DEG C, therefore it is required that the material of heavy-duty freight car hitch has high intensity, high-plasticity, low-temperature impact-resistant performance is good, endurance, wearability are good feature; Present common problem is, improves intensity often to lose toughness for cost. New E+level cast steel, compared with Ministry of Railways E level cast steel, utilizes the peculiar chemical constitution of rare earth, while ensureing toughness index, improves the intensity index of material, it is ensured that the plasticity and toughness deposit of material, it is prevented that infant cracking and brittle fracture occur, improves security reliability.

Rare earth is more and more extensive as the application in steel of a kind of alloy addition. The analysis and research of the existing use E level steel by railway standard is specified, we are on the basis of existing E level steel, by the research to rare earth element, steel adds a small amount of rare earth element, and study, adjust alloying element component, content, develop the E+ level steel that performance is more excellent, be applied to 16 types, 17 type hitch foundry goods, harmonious No. 2 locomotive couplers and related accessory thereof, service testing, meets the demand of the railway wagon heavy duty day by day improved.

Summary of the invention:

It is an object of the invention to the defect for prior art and deficiency, by adjusting the alloy compositions such as Mn, Ni, Cr, add the rare earth element of peculiar chemical constitution, it is provided that a kind of produce simple, cost is low and has the E+ level cast steel of high intensity.

The present invention is realized by techniques below scheme:

A kind of containing rareearth high-quality E+ steel, the weight percent content of its constituent is: C:0.20-0.30, Si:0.20-0.50, Mn:1.20-1.70, Cr:0.30-0.80, Ni:0.35-0.80, Mo:0.10-0.30, P≤0.01, S≤0.01, Cu≤0.30, RE:0.02-0.2%, all the other are Fe and trace impurity.

Preferred La or Se of RE.

The high-performance E+ steel of inventive formulation, its strength range is:

Yield strength ReL >=800MPa; Tensile strength Rm >=950MPa; Elongation percentage A >=14%; Contraction percentage of area Z >=30%; Impact flexibility (-40 DEG C) KV2 >=31J.

The invention have the advantage that this steel grade has alloying element few, alloy content is low, and intensity is high, and production technology is simple, low cost and other advantages, it is adaptable to superhigh intensity rolling stock steel-casting. This steel grade, by adjusting heat treatment, has excellent intensity and impact flexibility, and this steel grade has high fatigue strength and wearability simultaneously.

Detailed description of the invention:

The present invention is a kind of containing rareearth high-quality E+ steel, and its design theory is as follows:

C is the main intensified element in steel, and the carbon content improved in steel will increase martensite transfor mation ability, thus improving the intensity of steel, but the toughness of steel is existed appreciable impact by C content equally. C content of the present invention controls: 0.20-0.30%

Si is the deoxidant element in steel, and Si content is lower than 0.20%, and deoxidation effect is poor, and when Si content is higher, welding crack sensibility increases, and Si content of the present invention control is: 0.20-0.50%

Mn is the important solution strengthening element in steel. S in Mn and steel combines and forms MnS, thus avoiding the formation of FeS in steel. But, during Mn too high levels, Low Temperature Impact Toughness of Heat-affected Zone significantly reduces. The present invention controls Mn content: 1.20-1.70%

Ni can pass through grain refinement and the intensity of solution strengthening raising steel. Ni can reduce the tough transition temperature of steel while not reducing steel upper mounting plate ballistic work, and in order to ensure the toughness of steel, the present invention controls Ni content and is: 0.35-0.80%

Cr chromium forms solid solution with ferrum, the carbide with carbon forms various ways, improves the intensity of steel, hardness and wearability, improves the quenching degree of steel. The present invention controls Cr content: 0.30-0.80%

Mo is carbide former strong in steel, it is possible to suppress the transformation of pro-eutectoid ferrite, promotes the transformation of bainite. Mo can significantly improve the intensity of steel, and toughness is not damaged, and has the effect suppressing temper brittleness simultaneously. The present invention controls Mo content: 0.10-0.30%

Re has extremely strong chemism, steel adds after Re can cleaning molten steel, improve form and the distribution of non-metallic inclusion, improve the tissue of steel, improve the impact flexibility of steel, improve cryogenic property. Adding rare earth element in alloy cast steel, carbon cast steel, utilize its distinctive physicochemical characteristics, to the mechanical property improving foundry goods, improvement, process for stabilizing performance have very good effect. The present invention controls RE addition 0.02%-0.2%. Preferably, RE is La system and Se system.

Table 1 show the chemical composition of the present invention; Table 2 show the mechanical property of the present invention; Table 3 show the heat treatment process parameter of the present invention

The chemical composition % of table 1 present invention

The mechanical property of 2 present invention of table

The heat treatment process parameter of table 3 present invention

The technological process of production:

Electric arc furnace smelting (fusing, oxidation, intensification, tapping) LF furnace bottom Argon connects molten steel LF stove refine (reduction, adjusting component, temperature)

Electric arc furnace-LF stove smelting process, is greatly lowered the impurity harmful elements such as N, O, S, P in steel, it is achieved the smelting of high cleanliness molten steel, and rare earth element effect in steel can more effective obtain controlling and better being played. Utilize the distinctive physicochemical characteristics of rare earth, by preferred chemical composition, obtain the E+ level steel of high-strength tenacity.

Relatively describing the present invention following by different embodiments and comparative example, these embodiments are only for the purpose explained, the invention is not limited in these embodiments.

Table 4 is the chemical composition in embodiment and comparative example, and wherein 1-3 steel is example, and 4-5 steel is comparative example, and comparative example 4 steel is the E level steel of high Ni, and comparative example 5 steel is the E level steel of high C, high Mn, carbon equivalent high. Table 5 is the conventional mechanical property of embodiment and comparative example steel.

The chemical composition % of table 4 embodiment

The mechanical property of table 5 embodiment

Claims

1. containing a rareearth high-quality E+ steel, it is characterized in that: the weight percent content of its constituent is:

C:0.20-0.30, Si:0.20-0.50, Mn:1.20-1.70, Cr:0.30-0.80, Ni:0.35-0.80, Mo:0.10-0.30, P≤0.01, S≤0.01, Cu≤0.30, RE:0.02-0.2%, all the other are Fe and trace impurity.

2. one according to claim 1 is containing rareearth high-quality E+ steel, it is characterized in that: RE is La or Se.